In a study published June 19 in Science Immunology, researchers evaluated a two-part vaccination against genital herpes. With the technique, the first part — a typical intramuscular injection like you would receive for a flu shot, for example — is followed by the introduction of nanoparticles to the vagina, where herpes infection occurs in women.

The idea is the initial injection “primes” the immune system while the second localized treatment “pulls” immune activity right to where infection takes place. This study extends the original “prime and pull” approach by developing a new nanoparticle that effectively induces local immunity.

“We’ve found that, in preclinical experiments, this approach is a safe way to recruit the right immune cells in the right place to generate protective immunity,” said senior author Akiko Iwasaki, Sterling Professor of Immunobiology at Yale School of Medicine.

A two-pronged vaccine for genital herpes immunity

Efforts to develop a genital herpes vaccine have uncovered a key limitation of typical intramuscular injections: They do not establish robust immune cell populations or antibodies against the herpes virus at the vaginal lining where the virus is introduced in women. This limits the extent of immune attack against the herpes virus.

To address this challenge, the Iwasaki lab has explored methods to “pull” an immune response to the vaginal lining. They first tested whether introducing chemokines — proteins that can direct immune cells — to the vagina could establish immunity there. That technique led to only partial protection against herpes as it did not engage necessary immune cells called B cells.

They then evaluated a DNA molecule that stimulates the immune system. While it did reduce the amount of virus at the vagina, it also caused inflammation.

So the researchers wondered if combining the two methods might yield the best of both worlds.

“We had these two really promising strategies in the lab, but each had some shortcoming,” said Sachin Bhagchandani, a postdoc in Iwasaki’s lab and lead author of the study. “So we set out to formulate a particle that could overcome those shortcomings.”

Nanoparticles prevent herpes infection

The result of that work is BEACON (Bioactive Enhanced Adjuvant Chemokine Oligonucleotide Nanoparticles). The researchers made these nanoparticles by linking a piece of immunostimulating DNA to a chemokine.

“Sachin led this work, creating a nanoparticle that was stable and effective, which was no small feat,” said Iwasaki, who is also a professor of dermatology and of epidemiology, as well as an investigator with the Howard Hughes Medical Institute.

For the study, the researchers first primed female mice with an intramuscular vaccination against the herpes virus and then applied BEACON and virus antigen intravaginally. They found that BEACON established strong immune cell and antibody responses against the herpes virus in the vaginal tissue and that it lasted long term, at least six months.

When exposed to the herpes virus, mice given the “prime and pull” treatment were highly resistant to infection: 80% displayed no signs of disease over six months. That’s compared with just 40% of mice that received the intramuscular injection alone.

“That showed us that this approach could be profoundly impactful, establishing local immune responses for a significantly long period of time,” said Bhagchandani.

Further, BEACON enabled the researchers to target the right cells for generating immunity, rather than broadly affecting all cells. This meant they needed less of the DNA molecule than they used in previous experiments, and this smaller amount prevented the development of inflammation.

“This formulation is quite remarkable in that way,” said Iwasaki.

A vaccine for humans

The researchers are now evaluating whether this “prime and pull” method can be used to treat infection as well as prevent it. They’re also thinking about what this might look like for people.

“We’re collaborating with the Appel lab at Stanford to see if we can turn BEACON into translatable formulation, such as a vaginal suppository,” said Bhagchandani. “We’re also exploring a nasal approach wherein the ‘pull’ happens in the nose, which would allow this kind of treatment to work for men as well.”

While further down the road, the researchers aim to test this method in human clinical trials, because ultimately, the goal is to develop a vaccine for humans.

“A lot of the suffering patients go through is not just physical; it’s mental and societal,” said Iwasaki. “But viruses are the same — whether it’s the flu or Epstein-Barr virus or herpes simplex, it’s not the person’s fault that they caught it. And yet there’s a lot of stigma. We hope that this kind of strategy will prevent diseases that affect people in a profound way.”

Two succinct articles in CMAJ (Canadian Medical Association Journal) provide information about each disease for clinicians.

Hantavirus:

1. A nationally notifiable disease in Canada — In Canada, 4 to 5 cases are confirmed every year and must be reported. These are usually acquired from rodents in agricultural settings in Manitoba, Saskatchewan, Alberta, and British Columbia. The Andes strain is unique as it can be transmitted from person to person.
2. Causes 2 clinical symptoms — Strains in the Americas, which include the Andes virus featured recently in the news, cause hantavirus cardiopulmonary syndrome. The European and Asian strains cause hemorrhagic fever and kidney dysfunction. Both forms take about 2 to 4 weeks to incubate, and symptoms include fever, headache, muscle aches, and abdominal pain.
3. Serology and polymerase chain reaction (PCR) tests are diagnostic — The National Microbiology Laboratory in Winnipeg performs these tests.
4. Supportive treatment — As there is no specific antiviral treatment or vaccine for hantavirus, treatment is supportive to help alleviate symptoms.
5. IPAC protocols are essential — Patients with suspected Andes strain infection must be isolated with airborne, droplet, and contact precautions, with infectious diseases experts involved and public health notified.

Ebola virus disease:

1. Sporadic outbreaks have occurred in Central and West Africa since 1976 — There are 3 main viruses that can infect humans, and evidence suggests they come from fruit bats. Ebola virus is spread via person-to-person contact through bodily fluids like vomit, sperm, diarrhea, and blood, as well as by touching infected surfaces or objects. The current outbreak in the Democratic Republic of Congo is Bundibugyo ebolavirus, with a fatality rate of 30% to 50%.
2. Fewer than 50% of patients have hemorrhagic symptoms — Symptoms include fever of 38°C or higher, fatigue, muscle pain, and gastrointestinal distress. Incubation is 2 to 21 days, and diagnosis is made with PCR testing.
3. People with potential symptoms and exposure risk should be tested — People who have travelled to countries with Ebola virus disease or who have been in close contact with infected people or bats, primates, or game from the affected areas should be tested.
4. Stringent IPAC must be used for suspected cases — Health Canada has a detailed process for screening, assessment, and IPAC precautions, which must include a fit-tested N95 respirator, face shield, gloves, and fluid-impermeable gear for full protection.
5. Important advances in prevention and management of the disease have been made — Vaccines to prevent Zaire ebolavirus are very effective, and 2 antivirals can reduce mortality from 50% to 35%. However, there are no current vaccines or medications to prevent or treat Bundibugyo ebolavirus, for which supportive care is the main approach.

The findings, published in the Journal of Emergency Medicine, suggest that EDs could play an important role in increasing vaccine coverage, particularly among medically underserved populations.

Led by Dr. Robert Rodriguez, a professor of medicine in the UCR School of Medicine, the researchers surveyed 3,285 adult patients at 10 emergency departments in eight U.S. cities between April and December 2024. Nearly all participants (96%) had heard of the influenza vaccine, and 77.6% reported receiving a flu vaccine at some point in their lives. However, 58.4% had not received a flu vaccine within the past year and were therefore not up to date with current recommendations.

The study also identified significant disparities in vaccination status. Patients without a primary care provider were more than twice as likely to be behind on influenza vaccination, with lower vaccination rates also seen in patients lacking insurance and African American patients.

Among participants who were not up to date on their flu vaccination, 37% said they would accept a flu shot if it were offered during their emergency department visit.

“Emergency departments are often the only point of contact with the health care system for many patients,” said coauthor Dr. Rajesh Gulati, a professor of medicine in the UCR School of Medicine. “Our findings show that there is a substantial opportunity to reach people who may not have access to primary care and help close important gaps in influenza vaccination coverage.”

Influenza remains a major global public health threat, contributing to an estimated 650,000 deaths worldwide each year. Despite longstanding recommendations for annual vaccination, fewer than half of U.S. adults received a flu vaccine during the 2023–2024 season.

The researchers found that lack of primary care access was the strongest predictor of being behind on influenza vaccination. More than one in five study participants reported not having a primary care provider.

“The message from this study is clear: many patients who are either unaware of or not receiving preventive care elsewhere are willing to be vaccinated when given the opportunity,” said Sanya Dhama, first author of the paper and a medical student at UCR. “Emergency departments can serve as a critical public health safety net — not only for acute care, but also for preventive services such as influenza vaccination.”

Among patients who declined vaccination in the emergency department, the most common concerns were fear of vaccine side effects, a desire for more information about vaccines and influenza, and feeling too ill at the time of the visit.

“These findings suggest that educational messaging and targeted outreach could further improve acceptance,” Rodriguez said.

The cross-sectional study was conducted at EDs in Chicago, Detroit, Durham, Philadelphia, Fresno, Los Angeles, San Francisco, and Sylmar. The researchers surveyed adult patients regarding their knowledge of influenza vaccination, vaccination status, willingness to receive a flu shot in the emergency department, and reasons for vaccine acceptance or refusal.

“Emergency departments represent an underutilized venue for influenza vaccination surveillance, education, and vaccine delivery,” Rodriguez said. “Expanding ED-based vaccination programs could help reduce influenza-related illness, hospitalization, and death, particularly among populations with limited access to routine health care.”

The study was supported in part by the National Institute of Allergy and Infectious Diseases.

Rodriguez, Gulati, and Dhama were joined in the study by Shaokui Ge at UCR; Dr. Jesus Torres at UCLA; Dr. Brian Chinnock at UCSF Fresno; Dr. Michael Gottlieb at Rush University Medical Center, Illinois; Dr. Vijaya Arun Kumar at Wayne State University, Michigan; Dr. Kristin L. Rising and Dr. Efrat Rosenzweig Kean at the Thomas Jefferson University Hospital, Pennsylvania; Dr. Stephanie Eucker, at the Duke University School of Medicine, North Carolina; Dr. Melanie F. Molina at UC San Francisco.

The title of the paper is “Up to Date Status and Acceptance of the Influenza Vaccine among a National Sample of Emergency Department Patients.”

“In the United States, that’s hundreds of thousands, if not a million cases of flu that we can avoid each year,” said senior study author Anupam Jena, the Joseph P. Newhouse Professor of Health Care Policy in the Blavatnik Institute at HMS. “That’s a huge effect size.”

The findings provide additional support for the flu vaccine at a time when childhood vaccines have come under scrutiny in the United States. This January, the U.S. Centers for Disease Control and Prevention removed the annual influenza vaccine, as well as several others, from its childhood schedule of recommended vaccines. That change, which was widely condemned by medical societies and public health organizations, was blocked by a U.S. District Court in March.

“The federal government cited an absence of evidence that they want to see, and so we have provided that,” said Christopher Worsham, HMS assistant professor of medicine at Massachusetts General Hospital and first author on the study. “We have randomized data, and it shows that flu vaccines are effective for these young children.”

Sorting by birthday

Young children typically have an annual visit to the doctor scheduled around their birthday. For children born in the fall, those visits are a convenient time to get the flu vaccine. But children born in the summer will likely have appointments before the flu vaccine becomes available — they need an additional appointment to get vaccinated.

In previous research, Jena and Worsham found that the additional burden on caretakers results in lower flu vaccination rates in summer-born children. This creates a natural experiment, randomly sorting children into more- or less-vaccinated groups based on the happenstance of when they were born.

The researchers compared insurance claims data for summer-born and fall-born children between the ages of 2 and 5 over five flu seasons between 2016 and 2023. (They skipped the 2020-2021 and 2021-2022 seasons because of confounding factors from COVID-19.)

In each season, fall-born children were more likely to be vaccinated and less likely to catch the flu.

The vaccination rates for children with fall birthdays were between 8.6 and 12.5 percentage points higher than those with summer birthdays and the influenza diagnosis rates were 1.0 to 1.4 percentage points lower.

“Across these five seasons, we see that for every hundred kids who are randomly vaccinated because of when their birthday falls, somewhere between nine and 14 of them avoid a case of the flu that they otherwise would have caught,” said Jena, who is also a professor of medicine at Mass General.

For other illnesses that do not have vaccines, such as the common cold or gastrointestinal viruses, there was no difference in the infection rates of the two groups.

“It comes down to: vaccines work,” Worsham said.

More natural experiments

As children get older, birthdays and doctor’s appointments stop being so closely aligned. The researchers note that after about age five, the influenza diagnosis rates between fall- and summer-born children start to even out.

“The randomized data we have is limited to these very young children because their doctor appointments are tied to their birthday,” Worsham said.

That doesn’t mean that the vaccine isn’t effective in older children, teenagers, or adults — it definitely is, Worsham said. But after a certain age, birthdays are no longer good indicators of whether someone is more or less likely to have received the flu vaccine, so this experiment can’t capture vaccine effectiveness in older groups.

This work is just one example of a randomized experiment that can be found in existing data — there are many similar opportunities across different fields of medicine, the researchers said. Jena and Worsham are frequent collaborators and have co-authored a book, Random Acts of Medicine, on the subject.

“It is impossible to do a randomized controlled trial for every single thing that we want to know and understand,” Jena said. “But we have an incredible amount of data out there and there are randomized experiments like this sitting in that data, waiting to be uncovered.”

Authorship, funding, disclosures

Charles F. Bray, HMS hourly research assistant in health care policy and master’s student at Havard T.H. Chan School of Public Health, is co-author of the study.

This research was not directly supported by any funders.

The authors report no conflicts of interest related to this work. A full list of disclosures can be found in the paper.

The initiative is part of a wider effort to support clinicians and the public in understanding the robust regulatory system that underpins vaccine safety. It shows how regulators require strong evidence to approve vaccines, but also highlights how real-world evidence is collected from millions of doses after vaccines become available to the public.

The first Vaccine Essentials publication focuses on Meningococcal group B vaccines (MenB). MenB vaccines were chosen in part because the story of how they are regulated illustrates the value of combining immunogenicity data (which shows that the vaccine induces an immune response) with real-world effectiveness studies that determine impact of a vaccine in a clinic.

‘In the case on MenB vaccines, by supplementing the initial evidence (pre-approval) with additional data (post-approval), regulators were able to further confirm the vaccines’ safety, effectiveness, as well as their favourable benefit/risk balance,’ the EMA says.

The MenB factsheet was developed with the European Academy of Paediatrics and based on a peer-reviewed publication. ‘MenB vaccines represent a success story on the prevention of a very serious disease mainly affecting infants and teenagers,’ said Dr Hans J. Dornbusch of the European Academy of Paediatrics. ‘In clinical practice, in a child with fever, if all meningococcal immunisation is up to date, the risk of severe illness including meningitis is really low.’

The Agency has also assembled a new advisory group on vaccine confidence, bringing together international experts to advise on how to build and maintain trust in the regulatory system. Rather than championing vaccines per se, the regulator seeks to ensure that important health decisions are taken based on evidence and a sound understanding of science.

“Kaiser Permanente has led the way on this important innovation — first through trials showing that HPV self-collection is an effective and cost-efficient approach to increasing cervical cancer screening, and now by evaluating the adoption of this approach throughout Kaiser Permanente Washington,” said lead researcher Beverly Green, MD, MPH, a family physician and senior investigator with Kaiser Permanente Washington Health Research Institute (KPWHRI). “The response from clinicians and patients has been extremely positive.”

The evaluation included more than 95,000 Kaiser Permanente Washington members ages 30 to 64 who were due or overdue for screening during 6-month periods either before or after the HPV self-collection program began. Comparing the 2 groups, the researchers found that after the program started:

• Cervical cancer screening completion increased significantly, by 2.2% on average.
• Screening gains were higher among Black/African American, Asian, and Hispanic populations.
• The number of clinician-performed pelvic exams for screening dropped by more than a third, with 37% of patients completing screenings via self-collection.
• For people with screening results positive for high-risk HPV, follow-up colposcopy rates improved from 50% pre-program to 75.8% post-program, with support from a centralized safety-net system focused on outreach and follow-up.
• In interviews and site visits, clinicians highly favored the program overall, noting that it improved appointment access due to fewer pelvic exams, allowed for more time to address other health concerns, and offered patients a more comfortable and convenient screening option.

The research was conducted by the Center for Accelerating Care Transformation (ACT Center), which is part of KPWHRI and leads Kaiser Permanente Washington’s Learning Health System Program. The study authors said their findings could offer a practical roadmap for health systems considering adoption of HPV self-collection — highlighting the importance of standardized workflows, electronic health record (EHR) tools, and reporting and safety-net systems, which are essential for managing follow-up care and ensuring program quality.

“This is a real-world example of a learning health care system in action,” said senior author Paula Lozano, MD, PhD, co-director of the ACT Center and senior associate medical director for research and translation with Kaiser Permanente Washington. “We are using research evidence to inform implementation, continuously evaluate performance, and iterate to better meet the needs of patients and clinicians.”

This study was funded through Kaiser Permanente Washington’s Learning Health System Program.

“While the risk is still low to the general public, we are seeing a virus with a high fatality rate transmitting person-to-person,” said Milton, whose research has shown how viruses such as COVID and the flu are transmitted in exhaled breath and has demonstrated the efficacy of masks for prevention.

“WHO should change its default response – the starting point should not be to downplay the risk of airborne transmission until it is definitively proven. ”

Milton worked with a group of international experts: Trisha Greenhalg at University of Oxford, David N. Fisman at University of Toronto, Amanda Kvalsvig at University of Otago, Lidia Morawska at Queensland University of Technology and Jonathan M. Samet at Colorado School of Public Health.

The group writes: “The starting point should be the immediate adoption of precautionary measures to reduce airborne transmission, such as respirator use by healthcare workers, [infected people] and their close contacts.” They also recommend WHO include guidelines on improving ventilation, avoiding unfiltered air recirculation and use of portable HEPA (high efficiency particulate air) filtration in all enclosed quarantine and transport settings.”

The group also provided more detail to the BMJ article in this substack.

The researchers who performed the analysis included Maimuna Majumder, PhD, MPH, the Inaugural Peter Szolovits Distinguished Scholar in the Computational Health Informatics Program at Boston Children’s, and their postdoctoral research fellow Anne Bischops, MD, a pediatrician and German National Academy of Sciences Leopoldina Fellow. The team evaluated the number of U.S. measles cases, outbreaks, their origination, and the levels of transmission. Their results suggest that measles is making a comeback in the US, spreading continuously for more than a year.

The latest string of U.S. outbreaks began in Texas in January 2025. Since then, outbreaks have spread to 45 states. When the U.S. was last recertified for measles elimination status in 2011, the country achieved all the measles elimination indicators established by the CDC’s National Immunization Program. But this year, according to this new research, most of the indicators are in the red.

Missed indicators of measles elimination status:

• Low number of cases with a cutoff of less than one case per 10 million people. As of early 2026, the U.S. had about 93 cases per 10 million people, exceeding this limit.
• Most of the measles cases should come from abroad rather than from internal spread. Since the start of 2025, only 6-7 percent of the measles cases came from abroad, meaning most cases derive from within the U.S.
• A limited number of outbreaks (a cutoff of approximately four) with no more than about six cases each. Last year in the U.S., 48 outbreaks resulted in more than 2,000 cases. And in early 2026, at least 19 outbreaks already resulted in more than 1,600 cases.
• A level of transmission less than one, meaning one infected person only spreads measles to fewer than one other person on average. The U.S. exceeded this rate more than 75 percent of the time since early 2025.

Indicators at risk:

• The country achieves four weeks with  all infections deriving from outside the U.S. Since the first infection in January 2025, the U.S. hasn’t gone four weeks without infections with 90% of cases acquired here.
• Herd immunity through vaccination. An estimated 95 percent of people need to receive two-doses of the measles vaccine to achieve herd immunity, typically given as part of the MMR (measles, mumps, and rubella) vaccine. However, the U.S. average vaccination rate of kindergartners in the 2024-2025 school year was 92 percent, meaning this indicator is at high risk. In Texas for example, vaccine rates range as low as 79 to 90 percent, according to an earlier study from the team.
• Measles cases don’t share a common viral strain. From ongoing genetic analyses, preliminary data show that the majority of cases share the same viral strain and are likely part of the same transmission chain.

“Declining vaccination rates have already been a warning sign that measles could return,” said Bischops. “However, losing status would be a clear and very concerning indicator.”

The researchers believe these findings make a strong case for vaccinating children to protect them from a young age.

“Viral infections aren’t all benign and a measles infection even when cleared can result in lifelong problems,” said Majumder. “Babies less than a year old are among those at greatest risk for severe complications, and the full impact on children exposed during the current outbreak may only show up years later.”

This data aims to provide insights/an early warning framework ahead of a meeting of the Pan American Health Organization’s expert panel in November 2026 to reevaluate the U.S.’s measles elimination status.

Research letters published in the Correspondence section include research findings and are externally peer-reviewed. Unlike Articles containing original data, research letters are shorter and the research they contain is usually preliminary, exploratory, or reporting on early findings.

Written by Vanessa McMains, PhD

The paper, “Economic evaluation of delaying the infant hepatitis B vaccination schedule,” is under embargo until 11am EST on April 27, 2026 in JAMA Pediatrics.

The longer the delay, the study found, the higher the cost in human life and health care, with costs ranging from $16 million to $370 million depending on the age at first vaccination and adherence to vaccination schedules.

Chronic hepatitis B is a leading cause of cirrhosis, liver failure, liver cancer and death, affecting 2.4 million people in the United States. Newborns have the highest risk: 90% of newborns who contract hepatitis B virus (HBV) will develop chronic infections and 25% will die prematurely from cirrhosis or liver cancer.

“Preventing HBV transmission at birth is a cornerstone of hepatitis B elimination efforts,” said Noele Nelson, professor of practice in the Department of Public and Ecosystem Health, the senior author of the study.

In December 2025, the federal Advisory Committee on Immunization Practices (ACIP) voted to delay the first dose of HBV vaccine for infants whose birth parent tests negative for the virus – a reversal of a 2018 recommendation to administer the vaccine to all infants within 24 hours of birth.

In this study, Nelson and her team used probabilistic models built on published scientific data about hepatitis B vaccine efficacy, transmission rates and disease progression to estimate the number of infections and health care costs various vaccine scenarios would incur.

Nelson compared models where vaccination is given at birth or delayed to age 2 months, 7 months, 4 years or 12 years, in children of HBV-negative birth parents, unknown birth parent infection status or both. Their models also consider cases where all children received all three recommended doses, or incomplete vaccination.

All projections showed that, in unvaccinated groups, more individuals progressed to chronic infection or serious complications like cirrhosis and liver cancer. This effect was amplified in scenarios where children do not receive all three doses as prescribed.

“Importantly, our study underestimates the costs and health outcomes associated with delays to administering the hepatitis B vaccine birth dose,” Nelson said. “Our model assumptions were conservative. For example, we didn’t include the increasing risk of getting HBV infection from members of their household or community, which could happen if the number of people with HBV infection increases.”

The latest ACIP recommendation was, in part, based on low HBV infections. Nelson argues that the low incidence of HBV infection in the United States is a direct result of the successful vaccination programs.

“Multiple studies have shown that the later children receive their first hepatitis B vaccination, the lower the probability they will complete their routine vaccination course,” Nelson said. “This policy may reverse this progress towards hepatitis B elimination.”

The recent ACIP decision also cited concerns about the safety of the hepatitis B vaccine and speculation that harms might outweigh the benefits of vaccination. Reviewing four decades of studies, including recent comprehensive safety reviews, Nelson did not find any evidence of serious adverse reactions such as seizures, other neurological disorders, infections or mortality.

“We found that over 35 years of data demonstrate long-term immunogenicity and likely lifetime protection from hepatitis B vaccines,” Nelson said. “We don’t find any advantage in delaying the first dose of this vaccine, and our findings favor maintaining a policy of universal hepatitis B vaccination at birth.”

Additional authors include Eric W. Hall of Oregon Health & Science University; Prabhu Gounder of the Los Angeles County Department of Public Health; and Heather Bradley of Emory University.

Through statistical analyses of information from the Centers for Disease Control, as well as pharmaceutical industry sales data, investigators found that US states with higher AIDS prevalence experienced significantly larger increases in syphilis after highly active antiretroviral therapy (HAART) became widely available—with these increases concentrated among men, while rates among women continued to decline—suggesting that changes in sexual behavior following the reduced perceived risk of HIV had broader public health effects.

Data indicated that in the absence of HAART, there would have been 81% fewer syphilis cases between 1996 and 2008.

“With syphilis now at a 60‐year high, these findings offer timely insight into how life‐saving innovations can reshape population behavior and highlight the need for complementary public‐health strategies,” said corresponding author David Beheshti, PhD, of the University of Texas at San Antonio.

URL upon publication: https://onlinelibrary.wiley.com/doi/10.1002/hec.70100

Researchers found that initially DAA treatment was concentrated among older adults and those with Medicare or commercial insurance, but over time, treatment has shifted toward younger patients and Medicaid beneficiaries. Specialist prescribing peaked in 2015 and then declined through 2025.

“Treatment levels being too low may help explain why hepatitis C prevalence hasn’t fallen (and may have even increased) in recent years,” said senior author Benjamin Rome, MD, MPH, a faculty member in the Division of Pharmacoepidemiology and Pharmacoeconomics in the Mass General Brigham Department of Medicine. “Elimination will require system-level changes, not just better screening.”

“Hepatitis C is a curable disease, but current treatment levels are substantially below what’s needed to achieve national elimination targets,” said lead author Sanjay Kishore, MD, a faculty member at the University of Viriginia School of Medicine and a former resident at Brigham and Women’s Hospital, a founding member of the Mass General Brigham healthcare system.

Authorship: In addition to Kishore and Rome, co-authors include Margaret Hayden, Micah Johnson, and Aaron S. Kesselheim.

Disclosures: Kishore and Hayden reported consulting for the Equal Justice Initiative. Kishore, Hayden, and Johnson reported being unpaid cofounders of EqualCure. Kesselheim reported serving as an expert witness in cases against Gilead, Johnson & Johnson, generic manufacturers, and pharmacy benefits managers and serving as a consultant for Alosa Health. Rome reported receiving grants from Humana, Elevance Health Public Policy Institute, and PCMA Foundation and personal fees from Alosa Health.

Funding: Kesselheim and Rome were supported by a grant from Arnold Venture.

Paper cited: Kishore S et al. “National Prescribing Trends of Direct-Acting Antivirals for Hepatitis C” JAMA DOI: 10.1001/jama.2026.3328

Catching influenza increases the short-term risk of cardiovascular conditions, and existing evidence has shown that the vaccine reduces the risk of heart attack and stroke by preventing flu infection in the first place. The new study, which included 1,221 adults aged 40 or older in Denmark, looked at whether cardiovascular risk was reduced even if people were infected with flu despite being vaccinated.

‘If confirmed by additional studies in other settings, this would strengthen the case for prioritising influenza vaccination among people at risk of heart disease or stroke and would support refining recommendations across Europe,’ says Dr Roberto Croci, Statens Serum Institut in Copenhagen.

The study used Danish health registry data from 2014 to 2025 and included individuals aged 40 and above with a first-ever hospital admission for a heart attack or stroke within a year after an influenza virus infection. It included all lab-confirmed flu virus infections that occurred during nine consecutive influenza seasons.

The study population comprised 660 males and 561 females aged 40 years and above, with a median age of 75. Most patients were hospitalised with a stroke (65%), while 35% had a heart attack.

The risk of a first-time hospitalisation for heart attack and stroke during the first week after testing positive for influenza was found to be significantly higher than for any other period before or after; it increased threefold for a stroke and fivefold for a heart attack. This increased risk was reduced by half for people who were infected but had been vaccinated against influenza for that influenza season.

The study did not account for differences in effectiveness between influenza vaccines, which can vary depending on how well the vaccine formulation matches the viral strains circulating in that season. It could also not assess whether vaccination timing or gender affected outcomes.

However, the results add to the growing importance of protecting against infectious diseases in people at risk of cardiovascular events. ‘Highlighting the dual protection offered by vaccination, against both infection and its cardiovascular complications, could have a substantial public health impact,’ the authors said.

Factoring the vaccine’s added protection against these conditions into economic and burden analysis could also help make a stronger economic case for influenza vaccination programmes.