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Sometimes it is easy to refer to “the pandemic” as something that already ended. The phrase alone can make COVID-19 seem historical. While the World Health Organization ended COVID-19’s designation as a global health emergency in 2023, the disease itself has not stopped exacting a heavy toll.

A recent study published in JAMA Internal Medicine examined COVID-19 illnesses, hospitalizations, and deaths in the United States from late 2022 through late 2024. The findings make clear that COVID-19 continues to impose a significant health burden year after year.

What Toll Did the Study Reveal?

From October 2022 through September 2023, researchers estimated that 43.6 million people in the U.S. became sick with COVID-19. During that same period, 1.1 million individuals were hospitalized, and more than 100,000 people died.

In the following year, from October 2023 through September 2024, illness estimates declined. Still, they remained substantial. Roughly 33 million COVID-19 illnesses were recorded. Nearly 900,000 people were hospitalized, and approximately 100,800 deaths occurred. The study’s authors conclude that COVID-19 remains a persistent health threat in the U.S.

The study drew its data from the COVID-19–Associated Hospitalization Surveillance Network. This large system captures information from around 10% of the total U.S. population. The dataset allowed researchers to examine patterns across age groups. The approach revealed who faced the greatest risks of severe disease and death.

One of the clearest findings was the disproportionate impact on older adults. Most severe outcomes, including hospitalizations and deaths, occurred among people aged 65 and older.

This age group makes up less than 20% of the U.S. population. But adults 65 and older accounted for 47.5% of COVID-19 infections. They also represented 67.5% of hospitalizations and 81.3% of deaths.

About 1% of adults in this age range were hospitalized for COVID-19 during the study periods. The authors linked these severe outcomes in older adults to immune decline. Age can reduce the body’s ability to mount strong responses to infection.

What Do These Results Mean?

COVID-19 outcomes were more severe than influenza in a similar timeframe. CDC data show influenza hospitalized more than 470,000 people and caused nearly 28,000 deaths. Flu remains an important and ongoing health concern. Yet the contrast highlights that COVID-19 continues to impose a higher overall health burden.

Authors said the persistent toll of COVID-19 reflects the continued importance of prevention. Vaccination remains the first line of defense against severe disease. Expand access to antiviral treatments is urgent, especially for older adults.

Even as public attention moves on, the data make clear that COVID-19 has not.

Conclusion

COVID-19 causes tens of millions of illnesses and over 100,000 deaths annually in the U.S. Older adults face the greatest risk.

Have an upcoming trip? Passport Health offers a wide variety of options to help keep you safe from disease, including vaccines. Call or book online to schedule your appointment today.

Logan Hamilton is a health and wellness freelance writer for hire. He’s passionate about crafting crystal-clear, captivating, and credible content that elevates brands and establishes trust. When not writing, Logan can be found hiking, sticking his nose in bizarre books, or playing drums in a local rock band. Find him at loganjameshamilton.com.

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Planning an international trip means thinking about a lot of things — flights, accommodations, visas. Vaccines often end up at the bottom of the list. That’s a mistake.

Diseases that are rare or nonexistent in the U.S. are common in many of the world’s most popular destinations. Some countries won’t even let you cross the border without proof of certain vaccines. A quick pre-travel visit to a travel health clinic can keep you protected — and keep your trip from getting cut short.

Here are seven vaccines to have on your radar before your next international trip.

Where Can I Get Travel Vaccines?

Passport Health is the largest travel medicine provider in the United States. At any of our clinics, a travel health specialist will review your itinerary, walk you through what’s recommended for your destination, and make sure you leave with everything you need — vaccines, documentation, and answers.

Passport Health is also an authorized yellow fever vaccine provider — important if you’re headed to parts of Africa or South America where proof of vaccination is required to enter the country. The CDC and WHO recommend visiting a travel health clinic at least four weeks before you leave.

1. Yellow Fever Vaccine

Yellow fever is a mosquito-borne virus found in parts of sub-Saharan Africa and tropical South America. There’s no treatment once you have it. Vaccination is your only protection.

It’s also the one travel vaccine that comes with serious border consequences. More than 40 countries require proof of yellow fever vaccination to enter, and some require it even if you’re just passing through an affected region. That proof has to be an official International Certificate of Vaccination — the “yellow card” — issued by an authorized provider like Passport Health. A note from your doctor won’t do it.

One dose, given at least 10 days before travel, is all you need. It’s considered valid for life. If you’re traveling anywhere in sub-Saharan Africa or South America, check the entry requirements for your specific destination well before your departure date.

2. Hepatitis A Vaccine

Hepatitis A spreads through contaminated food and water and is one of the most common vaccine-preventable illnesses travelers bring home. You don’t have to seek out street food to get it — a sit-down restaurant is just as capable of being the source if sanitation standards are different from what you’re used to.

The CDC recommends it for travel to much of Asia, Africa, Central and South America, and parts of Eastern Europe. A single dose is enough to protect you for the trip — it takes effect within about two weeks. The second dose, given six to twelve months later, extends that protection long-term.

If you’re doing rural travel or staying somewhere for an extended period, make sure this is on your list before you go.

3. Typhoid Vaccine

Typhoid fever is caused by Salmonella Typhi bacteria, picked up through contaminated food or water. It’s common in South Asia, Southeast Asia, sub-Saharan Africa, and Latin America — and it can get serious quickly without treatment.

There are two vaccine options. The injectable version is a single shot given at least two weeks before travel. The oral version is four capsules taken every other day — it has to be finished at least a week before you leave, and you can’t take it alongside antibiotics. Your Passport Health specialist can help you decide which makes sense for your trip.

4. Hepatitis B Vaccine

Hepatitis B is a liver infection spread through blood and body fluids. Many Americans got this vaccine as children, but the exposure risks abroad are different — and more frequent — than what most people encounter at home.

It’s recommended for travelers who might receive medical or dental care in-country, who plan to get tattoos or piercings abroad, or who are staying for an extended period in areas with high hepatitis B rates — which includes most of Asia, Africa, and parts of South America and Eastern Europe. Healthcare workers and long-term volunteers should make sure they’re covered before they leave.

The standard series is three shots over six months. If your trip is coming up sooner than that, there are accelerated schedules available.

5. Tdap (Tetanus-Diphtheria-Pertussis)

Tdap covers tetanus, diphtheria, and pertussis (whooping cough). Adults need a booster every 10 years, and a lot of people are overdue without realizing it.

Travel raises your exposure to all three. Minor cuts and wounds are common when you’re out exploring, and pertussis spreads easily in crowded places — airports, buses, group tours. If you’re not sure when your last booster was, it’s worth checking before your trip.

6. MMR (Measles, Mumps, Rubella)

Measles is rare in the U.S., but it’s still circulating in many parts of the world. Europe, Asia, Africa, and the Americas have all seen active outbreaks in recent years. The disease spreads through the air — you don’t need direct contact with someone to catch it.

If you were born after 1957, you should have two documented MMR doses. Many adults only received one as a child and may not have full protection. A second dose is safe even if you’re already immune, so if your records are unclear, go ahead and get it.

Traveling with an infant? The MMR vaccine can be given as early as 6 months for babies heading into high-risk areas. That early dose won’t count toward their routine schedule, but it will cover them for the trip.

7. Polio Vaccine

Most Americans think of polio as a solved problem. In the U.S., it is — the disease was declared eradicated here in 1979. But wild poliovirus still circulates in parts of Pakistan and Afghanistan, and vaccine-derived poliovirus outbreaks have been reported in Africa, the Middle East, and Southeast Asia — including in countries that see significant tourist traffic.

If you completed your childhood polio series and are now traveling to an at-risk region, you should receive a one-time adult booster of IPV (inactivated polio vaccine). Some countries, including Saudi Arabia for Hajj pilgrims, require proof of polio vaccination for entry.

This is one of the most commonly overlooked travel vaccines because it feels like ancient history. For anyone heading to endemic or outbreak-affected areas, it isn’t.

Which Seasonal Vaccines Do Travelers Need?

In addition to the seven vaccines above, there are three seasonal vaccines worth checking before any international trip. These don’t fit neatly into the “travel vaccine” category, but they matter for travelers.

Do I Need a COVID-19 Booster Before International Travel?

COVID-19 continues to circulate globally. An illness abroad — even a moderate one — can mean missed flights, unexpected medical costs, and a ruined trip. Updated boosters for the 2025–2026 season are available from Pfizer (COMIRNATY, ages 5+), Moderna (SPIKEVAX, ages 6 months+), and Novavax (NUVAXOVID, ages 12+). The CDC recommends staying current for everyone 6 months and older.

Should I Get a Flu Shot Before Traveling Abroad?

Flu season runs on a different calendar outside the U.S. In the Southern Hemisphere, peak season is April through September — which means a traveler heading to South America or Australia in June is walking into flu season, not away from it. The flu shot is recommended every year for everyone 6 months and older. October is the sweet spot for winter travel, but getting it any time before departure is better than skipping it. FluMist tends to work better in young children; Fluad is the preferred formulation for adults 65 and older.

Who Should Get the RSV Vaccine Before Travel?

RSV vaccines are now recommended for adults 60 and older, pregnant travelers between 32 and 36 weeks of gestation, and indirectly for infants through maternal vaccination or monoclonal antibody prophylaxis. Unlike the flu shot, this one isn’t annual — if you received it in a prior season, you don’t need another one. Three options are available: GSK and Pfizer’s protein-based vaccines have extensive real-world safety data, while Moderna’s mRNA option is newer. If you’re in an eligible group and haven’t gotten one yet, it’s worth taking care of before a long trip — especially if you’re headed somewhere with limited healthcare access.

How Early Should I Get Travel Vaccines?

The most common mistake travelers make is waiting too long. Multi-dose series like hepatitis B take months to complete. Even single-dose vaccines like hepatitis A need two weeks to become effective. The CDC recommends seeing a travel health specialist at least four to six weeks before departure — ideally closer to six to eight weeks.

A few things to take care of before your appointment:

• Look up your destination’s entry requirements on the CDC Travelers’ Health site or your destination country’s embassy page
• Pull together your existing vaccination records if you have them
• Note any health circumstances that might affect your vaccine plan — pregnancy, current medications, or a compromised immune system

Your Passport Health specialist will handle the rest.

Which Travel Vaccines Do I Need for My Trip?

Not every traveler needs the same vaccines. Where you’re going matters, but so does what you’re doing when you get there. A business traveler staying in a city hotel in Bangkok has a different risk profile than someone doing rural volunteer work in the same country.

Length of stay plays a role too. A short trip and a months-long placement call for different planning conversations. So does your health history — prior immunizations, current medications, and any underlying conditions can all affect what’s appropriate for you.

The easiest way to sort through it is to book a pre-travel consultation. A Passport Health specialist will go through your itinerary and health history and tell you exactly what you need — no guesswork required.

Travel Vaccine Timing: How Far in Advance?

Here’s a quick reference for how far in advance each vaccine needs to be given:

Most vaccines can be given at the same visit — there’s no problem receiving multiple shots the same day. If your departure is coming up fast, a Passport Health clinician can help prioritize based on your itinerary and available time.

Schedule a pre-travel appointment at Passport Health →

Do I Need to Carry Proof of Vaccination When Traveling?

Some countries check vaccination documentation at the border. For yellow fever, there’s no workaround — an official International Certificate of Vaccination is required, and a phone photo won’t cut it in every country.

A few habits worth building before you leave:

• Carry a physical copy of your vaccine records alongside a digital backup
• Save digital copies somewhere accessible offline, or in multiple locations
• Use the Passport Health mobile app to pull up your records on the go
• Keep in mind that losing documentation abroad may mean getting re-vaccinated before you can return

Passport Health issues official yellow fever certificates at the time of your appointment and supports digital record access through its app.

Frequently Asked Questions

What are the must-have vaccines before international travel?

For most international travelers, the core list includes yellow fever (where required), hepatitis A, typhoid, hepatitis B, Tdap, MMR, and polio. On top of those, seasonal vaccines — COVID-19 boosters, flu, and RSV for eligible groups — are worth checking before any trip. Your specific needs depend on destination and health history.

How far in advance should I get travel vaccines?

At least four to six weeks before departure, ideally six to eight. Some multi-dose series take months to complete, and even single-dose vaccines need two weeks to take effect.

Are travel vaccines necessary if I’m healthy and fully vaccinated at home?

Yes. Routine U.S. vaccinations don’t cover everything you might encounter abroad — diseases like typhoid, hepatitis A in certain regions, and yellow fever aren’t part of the standard domestic schedule. Being healthy reduces risk; it doesn’t eliminate exposure.

Can I receive multiple travel vaccines at the same time?

Yes. Most travel vaccines can be safely given at the same visit without any increased risk.

When is proof of yellow fever vaccination required?

Entry into more than 40 countries — particularly in sub-Saharan Africa and South America — requires an official International Certificate of Vaccination. Some countries require it even if you’ve only transited through a yellow fever-endemic region.

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When professional football teams prepare for matches, they study opponents carefully. Studying structure and strategy helps sports teams identify weaknesses in their rivals that they can exploit. Researchers used a similar process to study the dangerous fungus Candida auris. This deadly fungus has repeatedly shut down hospital intensive care units worldwide.

C. auris resists nearly all known antifungal medications used in hospitals. Finding a biological weakness could allow new therapies or repurposed drugs. Such treatments could finally help clinicians control this dangerous infection.

C. auris spreads easily and is almost impossible to eradicate. The fungus poses the greatest risk to people already critically ill. For this reason, hospital outbreaks have become disturbingly common.

The fungus can live quietly on human skin without immediate symptoms. Infections often spread through ventilators and other invasive medical equipment. Roughly 45% of infected patients eventually die from complications.

How Did Researchers Study C. Auris?

C. auris was first identified in 2008 under mysterious circumstances. Researchers still do not know where this dangerous fungus originally emerged. Since discovery, outbreaks have been reported in more than forty countries.

Health authorities now label the pathogen a serious global health threat. The World Health Organization lists it among critical priority fungal pathogens.

One major challenge is the fungus surviving unusually high temperatures. High salt tolerance further complicates eradication efforts in clinical settings. These traits suggested possible origins in tropical oceans or marine animals.

Scientists from the University of Exeter recently identified a promising breakthrough. They observed specific genes activating during active C. auris infection. This activity was tracked inside a living host organism. Their findings were published in Communications Biology.

To test infection behavior, researchers used Arabian killifish embryos. These embryos survive temperatures similar to the human body. This model allowed infection to be studied under human like conditions.

The researchers believe these genes reveal new biological targets for treatment. Their work could also support the repurpose of existing antifungal medications.

How Did Researchers Expose Weaknesses?

C. auris can shapeshift by forming long fungal filaments during infection. These filaments likely help the fungus search for nutrients.

Researchers tracked which genes activated or deactivated during infection stages. This process revealed possible biological vulnerabilities worth targeting.

Several activated genes created specialized pumps inside fungal cells. These pumps pull iron seeking molecules into the fungus. Iron is essential for C. auris survival and growth. Blocking iron access may weaken or kill the fungus.

This discovery identifies a possible weak point for future therapies. However, the research only establishes a foundation for further study. Scientists must now learn how to disrupt iron uptake safely.

Future studies will determine whether this pathway can be exploited clinically. Despite limitations, the findings offer renewed hope. The pathogen has long been persistent, untreatable, and deadly. This research opens a new direction for fighting C. auris infections.

Conclusion

Researchers identified iron uptake as a potential weakness in Candida auris infections. Targeting this pathway could enable new treatments or reuse repurpose antifungal drugs. Further research is needed before these findings can improve patient survival.

Have an upcoming trip? Passport Health offers a wide variety of options to help keep you safe from disease, including vaccines. Call or book online to schedule your appointment today.

Logan Hamilton is a health and wellness freelance writer for hire. He’s passionate about crafting crystal-clear, captivating, and credible content that elevates brands and establishes trust. When not writing, Logan can be found hiking, sticking his nose in bizarre books, or playing drums in a local rock band. Find him at loganjameshamilton.com.

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Flu activity surged in December 2025 and January 2026 during heavy holiday travel and celebrations. The increase appears in the latest data from the Centers for Disease Control and Prevention. CDC officials say flu transmission often accelerates during crowded winter gatherings.

The CDC reports at least 11 million illnesses this flu season. Hospitalizations reached 120,000 and fatalities climbed to 5,000 nationwide. These figures reflect surveillance data collected through December 27, 2025.

Health officials warn flu activity will continue rising as winter progresses. Experts say seasonal peaks tend to arrive after major holidays and travel periods. This trend raises concern for hospitals already facing staffing and capacity pressures.

What Strain is Causing the Surge?

A significant portion of cases involve a strain called subclade K. Subclade K is a novel variant linked to the H3N2 influenza lineage. H3N2 itself is a subtype of influenza A viruses.

Subclade K has circulated internationally since the summer of 2025. Global spread indicates the strain gained momentum before the U.S. season. This pattern raises concerns about immune escape and rapid transmission.

The CDC analyzed 163 H3N2 samples collected during September 2025. Genetic sorting showed 89% belonged to subclade K. These findings suggest the strain quickly became dominant.

Who is Most Vulnerable?

Pediatric flu deaths have already occurred during this season. Nine children have died from flu-related complications so far. Each pediatric death raises alarms among public health experts.

Last flu season saw 288 pediatric deaths across the United States. That total matched child fatalities during the 2009 H1N1 pandemic. The comparison highlights the severe impact of seasonal influenza.

CDC research shows most pediatric flu deaths involved unvaccinated children. Around 90% of pediatric deaths in 2024 lacked vaccination. Officials stress vaccination remains the strongest protective measure for children.

Where Is Flu Hitting Hard?

New York State reported unprecedented flu activity in late December. State officials recorded the highest weekly flu cases ever documented. Mandatory flu reporting in New York began in 2004.

By late December, New York logged more than 70,000 cases. This represented the largest single-week total in state history. The number marked a 38 percent increase from the prior week.

Total flu cases statewide rose to 189,312 by December’s end. Hospitalizations also surged sharply during the same period. Weekly hospital admissions climbed from 2,251 to 3,666 patients.

That increase represents a 63% rise in flu hospitalizations. Hospitals reported growing strain from the rapid influx of patients. Health systems warned resources could tighten if trends persist.

How to Prevent Spread

Health experts emphasize awareness and prevention remain essential. They recommend masking in crowded public places during high transmission. Handwashing with soap and warm water also reduces infection risk.

Officials stress prevention protects individuals and broader communities. High vaccination coverage helps limit hospital strain and fatalities. Public health experts urge continued vigilance throughout the season.

Conclusion

Flu activity continues rising nationwide, driven by travel, subclade K, and low vaccination. Millions of illnesses, rising hospitalizations, pediatric deaths, and record state surges highlight risk. Vaccination, masking, and hygiene remain essential to prevent severe illness and deaths.

Have an upcoming trip? Passport Health offers a wide variety of options to help keep you safe from disease, including vaccines. Call or book online to schedule your appointment today.

Logan Hamilton is a health and wellness freelance writer for hire. He’s passionate about crafting crystal-clear, captivating, and credible content that elevates brands and establishes trust. When not writing, Logan can be found hiking, sticking his nose in bizarre books, or playing drums in a local rock band. Find him at loganjameshamilton.com.

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Disease resurgence is tragic in a society centuries into medical progress. These comebacks become even more tragic when driven by misinformation.

Measles cases in the United States have reached 2,012, CDC reports show. Updated counts appeared in late January as Arizona outbreaks continued spreading. South Carolina outbreaks also expanded during the same reporting period. Three additional states issued warnings about possible measles transmission at airports.

The United States recorded 54 new measles cases in recent updates. The nation now wobbles near losing its measles elimination status. This measles-free designation was first achieved nationally in the year 2000.

Public health officials warn elimination loss could occur in coming months. Loss of elimination status may also occur over years. Total measles cases in 2025 were the highest since 1992. That year, health officials identified approximately 2,200 measles cases nationwide.

Why is Measles Surging?

Following 1992, vaccination efforts sharply reduced measles case numbers. These efforts dramatically increased childhood immunization coverage nationwide.

Recently, growing vaccine skepticism has reversed many earlier public health gains. This skepticism has directly fueled the current measles resurgence.

Experts stress that the measles, mumps, rubella vaccine remains safe and effective. When coverage exceeds 95 %, herd immunity protects most people.

However, kindergarten vaccination rates across communities have steadily declined. Rates measured 95.2% during the 2019–2020 school year. By the 2023–2024 school year, coverage dropped to 92.7%.

CDC estimates this decline added 280,000 at-risk kindergarten children nationwide. In 2025, 26% of measles cases involved children younger than five. Another 42% occurred among children aged five through 19.

Only 32% of measles cases affected adults aged twenty or older. Among reported cases, 93% involved unvaccinated individuals or unknown status. 11% of measles cases required hospitalization for medical care. 20% of hospitalized patients were preschool-aged children.

Public health officials recorded 50 measles outbreaks during 2025. This represents a sharp increase from the 16 outbreaks during 2024. Only 285 total measles cases were recorded nationwide in 2024.

Tragically, three measles-related deaths occurred in the United States during 2025.

Where Are Outbreaks Most Dramatic?

Arizona and South Carolina have experienced notable measles resurgences recently. By late December, Arizona reported 195 confirmed measles infections. The majority of Arizona cases occurred within Mojave County. Mojave County alone reported 191 confirmed measles infections.

Neighboring regions in Utah raised the combined regional total to 292. This outbreak ranked as the second-largest measles outbreak nationally in 2025. The largest outbreak occurred earlier in West Texas. By August, the West Texas outbreak exceeded 762 confirmed measles cases.

South Carolina has reported three additional measles cases recently. Its 2025 statewide total has now reached 159 confirmed cases. All South Carolina cases occurred after early July 2025. 156 cases stemmed from a single school-related outbreak. Every new South Carolina case links directly to that original outbreak.

State epidemiologist Linda Bell said most patients lacked measles vaccination. Approximately 95% of South Carolina patients were unvaccinated. She noted some infections spread within health care settings.

Heading into 2026, vaccination efforts must counter persistent misinformation. Increasing vaccine coverage remains essential to prevent elimination status loss. Without renewed action, measles elimination in the United States remains at risk.

Conclusion

Measles resurgence reflects falling vaccination rates driven by persistent misinformation. Children remain most affected, with outbreaks spreading through schools and communities. Restoring vaccination coverage is essential to protect lives and preserve elimination status.

Have an upcoming trip? Passport Health offers a wide variety of options to help keep you safe from disease, including vaccines. Call or book online to schedule your appointment today.

Logan Hamilton is a health and wellness freelance writer for hire. He’s passionate about crafting crystal-clear, captivating, and credible content that elevates brands and establishes trust. When not writing, Logan can be found hiking, sticking his nose in bizarre books, or playing drums in a local rock band. Find him at loganjameshamilton.com.

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Dengue is one of the world’s most widespread mosquito-borne viral diseases. It causes millions of infections every year worldwide. Nearly half the global population remains at risk today. Climate change continues expanding mosquito habitats, worsening global dengue transmission.

Some people infected with dengue never develop symptoms. Researchers believe these individuals hold clues for better dengue treatments. Their immune systems clear the virus without causing illness. For years, these cases were difficult to study directly.

New research published in Science Translational Medicine changed that. The study provided the clearest look yet at asymptomatic dengue infections. Researchers created a high-resolution single-cell immune map of silent cases. This offered rare insight into immune responses that defeat dengue safely.

How Did Researchers Map Dengue Immunity?

The research team included scientists from Thailand, the UK, and others. Key partners included Mahidol University and the Wellcome Sanger Institute. Together, they produced the first detailed map of asymptomatic dengue immunity. These findings may inform safer and more effective future vaccine designs.

Asymptomatic dengue cases usually go unnoticed by healthcare systems. People feel healthy and do not seek medical care. The virus is detectable in blood only briefly. This makes identifying asymptomatic cases extremely difficult.

Researchers overcame this using a five-year household surveillance study. They closely monitored contacts of people with confirmed dengue infections. This approach grew from Thailand’s DENFREE project, launched over a decade ago. Through this method, researchers identified eight asymptomatic dengue cases.

These cases were compared with mild and severe dengue infections. The comparison produced a dataset of over 134,000 immune cells. Researchers sequenced single-cell RNA and immune receptors. This allowed an unusually detailed view of immune system behavior.

What Did the Findings Reveal?

Clear immune differences appeared between symptomatic and asymptomatic patients. Asymptomatic cases shared common immune cell patterns. These included CD8 T cells, natural killer cells, and antibody-producing cells. Immune cells’ shared features distinguished silent cases from symptomatic infections.

Symptomatic patients showed immune markers linked to bodily stress. These stress signals were absent in asymptomatic individuals. Instead, antibodies responded to dengue without causing harmful inflammation. This suggests a balanced immune response protects without damaging tissues.

Other immune signals also differed between patient groups. Sidechain signaling appeared more frequently in symptomatic dengue cases. This compound may help explain why some infections become severe. It could serve as a future marker for dengue risk.

The findings highlight the power of single-cell research methods. These approaches reveal immune processes traditional studies often miss. The researchers made their entire dataset publicly available. They hope it supports future infectious disease research.

Ultimately, researchers aim to improve dengue vaccine development. Current vaccines struggle against dengue’s multiple virus subtypes. Vaccines inspired by asymptomatic immunity may overcome these limitations. Such vaccines could boost CD8 T cell responses while limiting harmful inflammation.

Conclusion

Researchers mapped asymptomatic dengue immunity, revealing how protection occurs without harmful inflammation. This detailed immune map may guide safer vaccines across dengue subtypes. Single-cell approaches could accelerate infectious disease research and future treatment design.

Have an upcoming trip? Passport Health offers a wide variety of options to help keep you safe from disease, including vaccines. Call or book online to schedule your appointment today.

Logan Hamilton is a health and wellness freelance writer for hire. He’s passionate about crafting crystal-clear, captivating, and credible content that elevates brands and establishes trust. When not writing, Logan can be found hiking, sticking his nose in bizarre books, or playing drums in a local rock band. Find him at loganjameshamilton.com.

Image courtesy of NIH.

Aging becomes obvious on holiday mornings as energy fades quickly. Children wake buzzing with excitement, while adults need several coffees. This same aging pattern appears inside the immune system. Key immune signals decline over time, but scientists discovered a workaround.

As people age, the thymus produces fewer immune system signals. Scientists found liver cells can temporarily replace these missing signals. With proper factors, liver cells support T-cell development. This process makes the immune system behave more youthfully.

How Does the Liver Support Immunity?

Aging weakens immune defenses by reducing T-cell numbers and responsiveness. Older bodies become more vulnerable to infections as immune responses slow. Researchers at MIT and the Broad Institute addressed this decline. They developed a temporary method to boost T-cell production.

T-cells normally mature inside the thymus near the heart. This organ produces cytokines and growth factors for T-cell survival. Thymic involution begins early in adulthood and steadily progresses. By age seventy-five, thymus function is nearly absent.

Previous strategies tried injecting T-cell growth factors directly into blood. Those methods risked dangerous side effects from widespread immune activation. Other teams explored stem cell transplants to regrow thymus tissue. The MIT researchers instead pursued a temporary internal factory approach.

The liver was chosen to replicate thymus signaling for several reasons. It remains efficient at protein production throughout aging. The liver also absorbs mRNA more easily than other organs. All circulating blood, including T-cells, passes through the liver.

Researchers identified three signals required for T-cell maturation and diversity. These signals were encoded into mRNA sequences. The mRNA was packaged inside lipid nanoparticles for delivery. These particles naturally collect in the liver after bloodstream injection.

Once in the liver, hepatocytes absorb the mRNA instructions. Cells then produce proteins encoded by the mRNA. The three encoded factors were DLL1, FLT3, and IL-7. Each factor supports immature T-cell survival, maturation, and diversification.

How Did Researchers Test This Approach?

Researchers tested this approach in aging mice models. The first group included eighteen-month-old mice mimicking middle-aged humans. Mice received repeated mRNA injections across four weeks. This maintained steady liver production of T-cell supporting signals.

Treated mice showed significant improvements in T-cell maturity and function. Researchers next examined vaccine response improvements. Mice were vaccinated using ovalbumin protein from egg whites. This allowed precise measurement of immune responsiveness.

The treated mice doubled their immune response to ovalbumin vaccination. Researchers also tested responses to cancer immunotherapy. Mice implanted with tumors received checkpoint inhibitor drugs. Those given mRNA treatment survived significantly longer.

All three immune factors were required for therapeutic benefits. No single factor alone produced the immune system improvements.

Researchers plan to test this approach in additional animal models. Future studies will examine effects on other immune cells and humans.

Conclusion

A recent study shows aging immune decline may be reversible using temporary liver signaling. mRNA-delivered factors restored T-cell diversity, vaccine response, and cancer therapy effectiveness. Researchers hope this strategy could offset immune aging effects in humans.

Have an upcoming trip? Passport Health offers a wide variety of options to help keep you safe from disease, including vaccines. Call or book online to schedule your appointment today.

Logan Hamilton is a health and wellness freelance writer for hire. He’s passionate about crafting crystal-clear, captivating, and credible content that elevates brands and establishes trust. When not writing, Logan can be found hiking, sticking his nose in bizarre books, or playing drums in a local rock band. Find him at loganjameshamilton.com.

Image courtesy of Maksim Goncharenok.

COVID-19 vaccines saved 2.5 million lives in four years. They are among the most effective public health tools ever developed. Like undeserved heroes, vaccines protect even amid widespread scandal and misinformation.

Vaccine skepticism continues spreading across social media and online spaces. Some rumors claim COVID-19 vaccines cause serious long-term health harm. Current scientific consensus does not support those claims.

However, a new large study from France reveals strong benefits and no harm from COVID-19 mRNA vaccines. The national cohort study found no increase in all-cause mortality. Adults received COVID-19 vaccines up to four years earlier.

Vaccination reduced death from severe COVID-19 by 74%. The study also found a 25% percent reduction in all-cause mortality.

Results were published in JAMA Network Open.

How Did Researchers Find the Drop in Mortality Rates?

This research is the first population-based study of all-cause mortality. Researchers directly compared vaccinated adults with unvaccinated adults. The study also examined long-term outcomes in younger populations.

Younger adults usually face lower risks from severe COVID-19. Researchers still wanted to assess long-term mortality impacts. This inclusive approach filled an important research gap.

Data came from the French National Health Data System. Researchers identified over 28 million adults aged 18 to 59. All participants were alive on November 1, 2021. This date served as the study’s baseline for long-term observation.

Of these adults, 22.7 million received at least one dose of the COVID-19 vaccine. Vaccinations occurred between May and October 2021.

The remaining 5.9 million adults were not vaccinated. Researchers tracked outcomes through March 2025. This provided nearly 45 months of follow-up data.

Researchers adjusted for demographics and 41 underlying health conditions. Even after adjustments, results showed strong protective effects. Vaccinated adults had 74% lower mortality rate from severe COVID-19.

Vaccination also reduced death risk from any cause by 25%. This protective effect was strongest shortly after vaccination. Six months after vaccination, mortality dropped by 29%.

What Are the Study’s Limitations?

The authors noted possible lifestyle-related study limitations. There are other legitimate explanations for improved survival among vaccinated people.

Preventing severe COVID-19 may stop other diseases from worsening later. COVID-19 can cause long-term damage that increases future death risk. Long-term COVID-19 effects include inflammation, heart disease, and Long COVID. These conditions can raise mortality risk years after infection. Vaccination may reduce these long-term health harms.

Vaccinated individuals may also access healthcare more easily. They may live in better resourced areas or practice healthier habits. These factors could support improved survival.

However, lower death rates persisted despite researchers accounting for factors favoring unvaccinated survival. For instance, vaccinated adults were often older than unvaccinated adults. Older age usually increases death risk.

Vaccinated individuals also had higher cardiometabolic disease rates. These conditions raise risks for heart disease and death. Despite this, vaccinated groups still had lower mortality.

This study stands out for its scale and design. Its dataset included a large population and broad age range. Researchers carefully addressed multiple confounding variables.

Conclusion

A large study found COVID-19 vaccines decreased death risk long-term. Vaccination reduced severe COVID-19 deaths and overall mortality rate. These findings counter misinformation and confirm vaccine benefits.

Have an upcoming trip? Passport Health offers a wide variety of options to help keep you safe from disease, including vaccines. Call or book online to schedule your appointment today.

Logan Hamilton is a health and wellness freelance writer for hire. He’s passionate about crafting crystal-clear, captivating, and credible content that elevates brands and establishes trust. When not writing, Logan can be found hiking, sticking his nose in bizarre books, or playing drums in a local rock band. Find him at loganjameshamilton.com.

Image courtesy of Gundula Vogel.

Fever acts like a locked vault that traps and destroys invaders. When pathogens enter, body temperature rises to eliminate threats. This defense mechanism evolved over millions of years. It remains one of the immune system’s first responses.

A newly discovered bird flu gene helps viruses survive fever. This finding raises serious concern among infectious disease scientists. If bird flu adapts for human transmission, fever may fail. That failure could dramatically worsen future pandemics.

Normal fevers usually stop human influenza viruses effectively. Bird flu viruses continue spreading despite elevated body temperatures. Fever normally shuts down viral replication. Bird flu appears able to resist this defense.

Why Does Bird Flu Resist Fever?

Fever played a crucial role during past flu pandemics. In 1957 and 1968, influenza viruses acquired a new gene. That gene helped the virus spread more efficiently and reduced sensitivity to heat.

Human flu infects millions of people worldwide each year. Influenza A is the most widespread seasonal flu strain. It mainly infects the upper respiratory tract. This area stays near 90°F (≈32°C).

Deep lung and brain tissues are warmer environments. These tissues average 99°F (≈37°C). If viruses survive there, they can spread systemically. This proliferation leads to severe and sometimes fatal illness.

Fever can raise body temperature very high. Temperatures may reach nearly 106°F (≈41°C). Heat slows viral replication significantly, preventing severe spread and saving countless lives.

Bird flu behaves differently than human flu strains. Avian viruses prefer deeper tissues in the body. They often infect gut tissues in birds. These regions remain very warm.

Bird digestive and respiratory tissues reach extreme temperatures. They range from 104 to 108°F (40 to 42°C). Bird flu evolved to thrive under these conditions. This adaptation may explain its fever resistance.

How Did Researchers Show Bird Flu’s Resistance?

Earlier studies hinted at bird flu’s heat tolerance. Those studies used cultured cells in laboratories. They showed survival at fever-like temperatures. The new study confirms this in living organisms.

Researchers infected mice with bird flu viruses. They examined how fever affected viral replication. Results showed fever alone may not stop bird flu. The virus continued spreading despite elevated temperatures.

The research team included scientists from Cambridge and Glasgow. They simulated human fever conditions inside mice and closely observed viral behavior. This procedure allowed precise temperature-controlled testing.

Researchers modified a human flu virus called PR8, which poses no threat to humans. Mice normally do not develop fevers from influenza. Scientists artificially raised their body temperatures.

Human flu stopped when temperatures increased. Bird flu continued replicating under the same conditions. This contrast revealed a key biological difference. Heat sensitivity varied dramatically between strains.

Human strains showed strong sensitivity to temperature increases. A rise of 3.6°F (2°C) reduced disease severity. Fatal infections became mild symptoms. Bird flu did not respond the same way.

The PB1 gene plays a major role in resistance. PB1 helps viruses replicate efficiently. Bird flu PB1 allowed viral survival during fever. Mice developed severe disease despite high body temperatures.

What Are the Future Risks?

This study’s findings highlight reassortment risks. Reassortment occurs when viruses exchange genes within one infected host. Pigs could act as “mixing vessels” that facilitate this genetic transfer.

If bird and human flu infect the same host, genes may swap. A fever-resistant, human-transmissible virus could emerge. This process is called spillover. Such an event would pose a serious global threat.

Conclusion

Bird flu’s heat resistance weakens one of the body’s strongest defenses. A single gene allows survival even at high fever temperatures. Reassortment could enable human spread, increasing the risk of severe pandemics.

Have an upcoming trip? Passport Health offers a wide variety of options to help keep you safe from disease, including vaccines. Call or book online to schedule your appointment today.

Logan Hamilton is a health and wellness freelance writer for hire. He’s passionate about crafting crystal-clear, captivating, and credible content that elevates brands and establishes trust. When not writing, Logan can be found hiking, sticking his nose in bizarre books, or playing drums in a local rock band. Find him at loganjameshamilton.com.

Image courtesy of Kampus Production.

Long COVID has few obvious links to other infectious diseases like tuberculosis. Yet, new research suggests hidden infections may activate alongside COVID-19. Viruses like Epstein-Barr could re-emerge as COVID-19 stresses immunity. This compound effect may explain fatigue, brain fog, and other Long COVID symptoms.

The study’s findings suggest coinfections may contribute to Long COVID development. These infections may exist before or emerge during COVID-19 infection. Their interaction with the immune system could drive persistent symptoms. This connection offers a new framework for understanding Long COVID mechanisms.

The study was published in eLife and led by 17 researchers. Many researchers involved were affiliated with Rutgers Health.

How are TB and EBV Linked to Long COVID?

Epstein-Barr virus (EBV) may be a major contributor to Long COVID symptoms. EBV causes mononucleosis and remains dormant in most adults. About 95 percent of adults carry latent EBV. It usually causes no symptoms or immune stress.

However, COVID-19 can weaken the immune system’s regulation of latent EBV infections. This disruption allows EBV to reactivate during or after COVID-19 illness.

Early studies found EBV markers in two-thirds of Long COVID patients. More severe symptoms correlated with higher EBV antibody levels.

Follow-up studies strengthened the EBV and Long COVID connection. Researchers linked EBV persistence to fatigue and cognitive impairment. These findings suggest viral reactivation may worsen Long COVID symptoms. EBV remains one of the strongest suspected contributors.

Tuberculosis (TB) may also play a role in Long COVID. About 25 percent of the global population has latent TB. COVID-19 infection may reduce immune activity that normally suppresses TB activity. This dampening effect could increase the risk of TB reactivation. TB may also worsen COVID-19 illness in some cases.

Why Might Coinfections Cause Long COVID?

The timing of coinfection appears to significantly affect outcomes. Preexisting infections may suppress immunity before COVID-19 exposure. Post-COVID infections may accelerate tissue damage. Infections emerging after recovery may exploit immune dysregulation.

COVID-19 can leave lasting immune system imbalances. These changes may increase vulnerability to other diseases by creating opportunities for dormant infections to resurface.

The authors identified disease surges across 44 countries. At least 13 diseases increased during the COVID-19 pandemic. These increases closely aligned with COVID-19 waves.

These findings, among others, led the authors to propose a concept called “immunity theft.” Immunity theft suggests severe COVID-19 infection weakens broader immune defenses. This impairment may increase susceptibility to other infectious diseases.

If the link is confirmed, existing treatments could target these coinfections. Antivirals or antibiotics might help reduce Long COVID symptoms.

Why Might Coinfections Cause Long COVID?

Clinical trials would be needed to test the immunity theft approach. Researchers must determine whether treating coinfections improves outcomes. This strategy could offer new options for Long COVID care. However, evidence remains limited.

The study’s authors emphasize their findings are preliminary. The proposed mechanisms are biologically plausible but unproven. More research is needed to confirm these connections. Large studies are required to validate the hypothesis.

Animal testing is especially challenging for Long COVID research. Reliable animal models for Long COVID remain rare. This limits researchers’ ability to test disease mechanisms.

Despite this, the authors remain hopeful that this work opens new research pathways. While it offers no immediate treatment guidance, the findings are significant. This lead may eventually help millions affected by Long COVID.

Conclusion

New research suggests Long COVID may involve reactivated or overlapping infections. Viruses like Epstein-Barr and latent tuberculosis may worsen symptoms after COVID-19. While evidence remains preliminary, this pathway could guide future treatments and research.

Have an upcoming trip? Passport Health offers a wide variety of options to help keep you safe from disease, including vaccines. Call or book online to schedule your appointment today.

Logan Hamilton is a health and wellness freelance writer for hire. He’s passionate about crafting crystal-clear, captivating, and credible content that elevates brands and establishes trust. When not writing, Logan can be found hiking, sticking his nose in bizarre books, or playing drums in a local rock band. Find him at loganjameshamilton.com.