An mRNA-based seasonal flu vaccine from Moderna was 27 percent more effective at preventing influenza infections than a standard flu shot, the company announced this week.
Moderna noted that the new shot, dubbed mRNA-1010, hit the highest efficacy target that it set for the trial, which included nearly 41,000 people aged 50 and above. Participants were randomly assigned to receive either mRNA-1010 or a standard shot and were then followed for about six months during a flu season.
Compared to the standard shot, the mRNA vaccine had an overall vaccine efficacy that was 26.6 percent higher, and 27.4 percent higher in participants who were aged 65 years or older. Previous trial data showed that mRNA-1010 generated higher immune responses in participants than both regular standard flu shots and high-dose flu shots.
The company noted that the positive results for the new trial come in the wake of one of the worst flu seasons in years. During the 2024–2025 flu season, the Centers for Disease Control and Prevention estimates that 770,000 people in the US were hospitalized for the flu.
“Today’s strong Phase 3 efficacy results are a significant milestone in our effort to reduce the burden of influenza in older adults,” Moderna CEO Stéphane Bancel said in a statement. “The severity of this past flu season underscores the need for more effective vaccines. An mRNA-based flu vaccine has the potential advantage to more precisely match circulating strains, support rapid response in a future influenza pandemic, and pave the way for COVID-19 combination vaccines.”
Outside researchers can request access to VSD data by submitting study proposals to the CDC. The Geiers have, in the past, gained access. But, they lost that access at least twice, the Journal reported. In 2004, the CDC kicked the Geiers out after officials determined that they had misrepresented their plans for the data when they initially submitted their proposal to the CDC. They were barred again in 2006.
Now an HHS employee, Geier is seeking access to the data once again. The Journal reports that Kennedy has assigned researchers at the National Institutes of Health to assist Geier and that those NIH employees have sent a request to the CDC to hand over all of VSD’s data. This request reportedly caused alarm at the CDC and the project’s health care sites around the country, which are concerned about protecting the security of private patient data.
It’s unclear whether Geier has regained access to the data. But people familiar with the matter told the Journal that Geier aims to reanalyze the CDC’s data on thimerosal to try to prove a link to autism. The sources also said that Geier is interested in proving that the CDC is corrupt.
In the May hearing, Kennedy, who also supports the debunked claim that vaccines cause autism, defended Geier. Kennedy said that “there has been a lot of monkey business with the VSD” and that Geier is “the only living independent scientist” who has seen the data and can determine if it has been altered. (Hassan interjected that Geier is not a scientist.) Kennedy also falsely claimed that a court overturned the medical board’s finding that he had practiced medicine without a license and awarded Geier $5 million.
That did not happen. But Kennedy may have been referring to the fact that Mark Geier filed a lawsuit against the medical board over a 2012 cease-and-desist order that alleged he improperly prescribed medication for himself, his wife, and his son while his medical license was suspended. Mark Geier sued the board, saying the order was malicious because it contained personal information, including the medications Geier had prescribed. A Circuit Court sided with the Geiers, awarding them nearly $5 million in total. But the win and the award were overturned on appeal in 2019.
For the new study, CDC researchers looked at RSV hospitalization rates across two different RSV surveillance networks of hospitals and medical centers (called RSV-NET and NVSN). They compared the networks’ hospitalization rates in the 2024–2025 RSV season to their respective rates in pre-pandemic seasons between 2018 and 2020. The analysis found that among newborns (0–2 months), RSV hospitalizations fell 52 percent in RSV-NET and 45 percent in NVSN compared with the rates from the 2018–2020 period. However, when the researcher excluded data from NVSN’s surveillance site in Houston—where the 2024–2035 RSV season started before the vaccine and treatment were rolled out—there was a 71 percent decline in hospitalizations in NVSN.
For a broader group of infants—0 to 7 months old—RSV-NET showed a 43 percent drop in hospitalizations in the 2024–2025 RSV season, and NVSN saw a 28 percent drop. Again, when Houston was excluded from the NVSN data, there was a 56 percent drop.
Lastly, the researchers looked at hospitalization rates for toddlers and children up to 5 years old, who wouldn’t have been protected by the new products. There, they saw RSV hospitalization rates were actually higher in the 2024–2025 season than in the pre-pandemic years. That suggests that the latest RSV season was more severe, and the drops in infant hospitalizations may be underestimates.
Cod liver oil contains high levels of vitamin A, which is sometimes administered to measles patients under a physician’s supervision. But the supplement is mostly a supportive treatment in children with vitamin deficiencies, and taking too much can cause toxicity. Nevertheless, Kennedy has touted the vitamin and falsely claimed that good nutrition protects against the virus, much to the dismay of pediatricians.
“They had a really good, quick recovery,” the mother said of her other four children, attributing their recovery to the unproven treatments.
Tragic misinformation
Most children do recover from measles, regardless of whether they’re given cod liver oil. The fatality rate of measles is nearly 1 to 3 in 1,000 children, who die with respiratory (e.g., pneumonia) or neurological complications from the virus, according to the Centers for Disease Control and Prevention.
Tommey noted that the sibling who died didn’t get the alternative treatments, leading the audience to believe that this could have contributed to her death. She also questioned what was written on the death certificate, noting that the girl’s pneumonia was from a secondary bacterial infection, not the virus directly, a clear effort to falsely suggest measles was not the cause of death and downplay the dangers of the disease. The parents said they hadn’t received the death certificate yet.
Tommey then turned to the MMR vaccine, asking if the mother still felt that it was a dangerous vaccine after her daughter’s death from the disease, prefacing the question by claiming to have seen a lot of “injury” from the vaccine. “Do you still feel the same way about the MMR vaccine versus measles?” she asked.
“Yes, absolutely; we would absolutely not take the MMR. The measles wasn’t that bad, and they got over it pretty quickly,” the mother replied, speaking again of her four living children.
“So,” Tommey continued, “when you see the fearmongering in the press, which is what we want to stop, that is why we want to get the truth out, what do you say to the parents who are rushing out, panicking, to get the MMR for their 6-month-old baby because they think that that child is going to die of measles because of what happened to your daughter?”
Ars Technica has reached out to the NIH and HHS for comment and will update this story with any new information provided. The agencies did not respond to comment requests from KFF.
Kennedy’s misinformation
Before becoming the top health official in America, Kennedy had long railed against vaccines, becoming one of the world’s most prominent anti-vaccine advocates and most prolific spreaders of misinformation and disinformation about vaccines. A 2019 study found Kennedy was the single leading source of anti-vaccine ads on Facebook. Kennedy subsequently faced bans from YouTube, Facebook, and Instagram for spreading misinformation.
Researchers directly blame Kennedy and the Trump administration for the attack on vaccine research.
“Kennedy’s war on vaccines has started,” the mRNA vaccine researcher in Philadelphia told KFF.
“There will not be any research funded by NIH on mRNA vaccines,” the scientist in New York similarly told the outlet. “MAGA people are convinced that these vaccines have killed and maimed tens of thousands of people. It’s not true, but they believe that.”
Kennedy has made various statements against vaccines generally, as well as mRNA vaccines specifically. He falsely claimed the vaccine causes severe harms, including causing neurodegenerative diseases, such as Parkinson’s. In 2021, during the height of the pandemic, Kennedy petitioned the Food and Drug Administration to revoke the authorization of COVID-19 vaccines and refrain from approving any future COVID-19 vaccines. A study in 2022, meanwhile, estimated that the vaccines had saved more than 3 million lives and prevented more than 18 million hospitalizations.
The NIH’s recent moves aren’t the first sign that Kennedy will use his powerful position to attack mRNA vaccines. Late last month, Bloomberg reported that HHS was considering canceling a $590 million grant to vaccine-maker Moderna to develop mRNA vaccines against potential pandemic influenza viruses. That includes the H5N1 virus that is currently devastating US poultry and spreading wildly in dairy cows.
An HHS spokesperson told media at the time that “while it is crucial that the US Department and Health and Human Services support pandemic preparedness, four years of the Biden administration’s failed oversight have made it necessary to review agreements for vaccine production.”
It remains unclear what is happening with that grant review. Moderna declined to comment when Ars reached out for any potential updates Monday.
With measles declared eliminated from the US in 2000 and national herd immunity strong, health experts have recommended that American children get two doses of the Measles, Mumps, and Rubella (MMR) vaccine—the first between the ages of 12 and 15 months and the second between the ages of 4 and 6 years, before they start school.
Before 12 months, vulnerable infants in the US have been protected in part by maternal antibodies early in infancy as well as the immunity of the people surrounding them. But if they travel to a place where population immunity is unreliable, experts recommend that infants ages 6 to 11 months get an early dose—then follow it up with the standard two doses at the standard times, bringing the total to three doses.
The reason they would need three—and the reason experts typically recommend waiting until 12 months—is because the maternal antibodies infants carry can interfere with the vaccine response, preventing the immune system from mounting long-lasting protection. Still, the early dose provides boosted protection in that 6-to-11-month interval.
In the past, this early, extra dose was recommended for infants traveling internationally—to countries that hadn’t achieved America’s enviable level of herd immunity and were vulnerable to outbreaks. But now, with US vaccination rates slipping, herd immunity becoming spotty, cases rising by the day, and outbreaks simmering in multiple states, the US is no longer different from far-off places that struggle with the extremely infectious virus.
In an article published today in JAMA, prominent health experts—including former Centers for Disease Control and Prevention Director Rochelle Walensky—call for the US to update its MMR recommendations to include the early, extra dose for infants who are not only traveling abroad, but domestically, to any areas where measles is a concern.
“With some local immunization levels inadequate to avert outbreaks and ongoing disease spread in various regions of the country, a dichotomy between domestic and international travel is not appropriate,” the experts write. “For many travel itineraries, there may even be a higher risk of measles exposure at the US point of departure than at the international destinations.”
Vaccinating at-risk infants early is critical to their own health—as well as the people around them, the experts note. “[I]nfants younger than one year face a heightened risk of severe measles-related complications such as pneumonia, encephalitis, and death. Younger infants are also at increased risk of developing subacute sclerosing panencephalitis (SSPE), a rare measles complication that has a high fatality rate and may surface years after initial infection,” according to the experts.
Phase I study showed vaccine was safe and spurred immune responses in older people.
An electron micrograph of norovirus. Credit: Getty| BSIP
In an early clinical trial, an experimental norovirus vaccine given as a pill produced defensive responses exactly where it counts—in the saliva of older people most vulnerable to the explosive stomach bug.
The results, published this week in Science Translational Medicine, are another step in the long effort to thwart the gruesome germ, which finds a way to violently hollow out innards wherever people go—from restaurants to natural wonders and even the high seas. It’s a robust, extremely infectious virus that spreads via the nauseating fecal-oral route. Infected people spew billions of virus particles in their vomit and diarrhea, and shedding can last weeks. The particles aren’t easily killed by hand sanitizers and can linger on surfaces for up to two weeks. Exposure to as few as 10 virus particles can spark an infection. According to the Centers for Disease Control and Prevention, norovirus causes an average of between 19 and 21 million cases of acute gastroenteritis in the US every year, leading to 109,000 hospitalizations and 900 deaths. This racks up an economic burden estimated to be $2 billion to $10.6 billion.
Vaccine design
For most, the gut-busting bug is miserable but usually over in a few days. But older people—especially those with underlying medical conditions—are vulnerable to severe outcomes. About 90 percent of people who die from a norovirus infection are people age 65 or older who live in long-term care facilities.
For this reason, researchers have aimed to design a vaccine that’s sure to be effective in older people, who typically have weaker immune responses just from the aging process. But, of course, this makes the already daunting task of developing a vaccine yet harder—and norovirus poses some specific challenges. For one, there aren’t a lot of good laboratory models and animal systems to run norovirus experiments or test candidate drugs. For example, healthy mice infected with a mouse version of norovirus don’t develop any symptoms (lucky critters). Then there’s the fact that norovirus isn’t one virus; it’s many. There are 49 different genotypes of norovirus, which have been categorized into 10 “genogroups.” It’s unclear if protection against one genotype or genogroup will help protect against the others, and if so, by how much.
Currently, there are several norovirus vaccines in the works, at various stages with various designs. The one published this week is being developed by a San Francisco-based company called Vaxart and uses a proprietary oral delivery system. The pill includes a deactivated virus particle (an adenovirus), which can’t replicate in people but can deliver the genetic blueprints of two molecules into cells lining our intestines. One of the genetic blueprints it delivers tells the intestinal cells how to manufacture a protein found on the outside of norovirus particles, called VP.1. Once manufactured in the intestines, VP.1 can train the immune system to identify invading norovirus particles and attack them. The other genetic code included in the vaccine is for what’s called an “adjuvant,” which is basically a booster molecule that helps rev up immune responses.
While several other vaccines in the works are delivered by injections, producing systemic responses, the idea of the pill is to build up immune responses to norovirus directly where it invades and attacks—the mucosal lining of the digestive tract, including the mouth and intestines. There is some preliminary data suggesting that having antibodies against norovirus in saliva correlates with protection from the virus.
Good news
Vaxart has previously published Phase I trial data showing that its pill is safe and well-tolerated in healthy adults ages 18 to 49. The study, published in 2018, also indicated that the pill generated “substantial” systemic and mucosal antibodies against norovirus.
For the new study, Vaxart did a repeat Phase I trial with 65 older people—ages 55 to 80, broken into groups of 55 to 65, and 66 to 80. The participants were randomly assigned to get either a placebo (22) or a low (16), medium (16), or high (11) dose of the vaccine VXA-G1.1-NN, which targets one genotype of norovirus. Again, the vaccine was safe and well-tolerated. There were no serious side effects. The most common side effects were headache and fatigue, which were reported at about the same rates among the placebo and vaccinated groups.
Further, detailed examination of the participants’ immune responses showed not only systemic response, but responses in distant mucus membranes. In the blood, two types of antibodies (IgA and IgG) increased by several fold after vaccination compared with the placebo group. The group with the largest responses was the one that received the high dose.
A test that acts as a surrogate for neutralizing antibody responses to norovirus indicated that the antibodies spurred by the vaccine could block the virus. Additional tests found that cellular immune responses were also activated and that the systemic responses result in protection in places far from the intestines—namely the mouth and nose. Saliva tests and nasal swabs found significant jumps in secreted IgA against norovirus.
Immune responses were strongest in the first two months after vaccination and diminished over time, but some persisted for nearly seven months. When the scientists looked at differences between the two age groups (55–65 and 65–80), they didn’t see significant differences, suggesting the vaccine was equally effective in the older group.
Overall, the scientists at Vaxart concluded that the vaccine “has the potential to inhibit infection, viral shedding, and transmission.”
“Overall, VXA-G1.1-NN administration in older adults led to robust and durable immunogenicity detected both in circulation and multiple mucosal sites, an exciting outcome considering that diminished cellular and mucosal immunity are typical in older populations,” they wrote.
Not so good news
The outlook isn’t entirely rosy, though—there is some bad news. While immune responses rose in statistically significant measures during this small early-stage trial, it’s unclear if that equates to real-life protection. And there’s some good reason to be wary. In 2023, Vaxart released results of a challenge study, in which 141 brave souls (76 vaccinated and 65 given a placebo) were deliberately exposed to norovirus to see if the vaccine was protective. The results were weak: 53 placebo-group members (81.5 percent) became infected with norovirus, as determined by a PCR test looking for genetic evidence of the virus in their stool—and so did 76 vaccinated people (60 percent). That worked out to the vaccine offering only a 29 percent lower relative risk of getting infected. Looking at whether infected people developed symptoms of acute gastroenteritis, the vaccine had a protective efficacy of about 21 percent: 34 vaccinated people (48 percent) versus 37 placebo-group members (57 percent) developed symptoms.
While the study was a disappointment, Vaxart wasn’t ready to give up, arguing that the challenge study used large-dose exposures that people wouldn’t encounter in the real world.
“We use lots of copies of virus to ensure a high infection rate. In nature, 10 to 15 copies of virus is generally enough to give certain susceptible individuals disease,” James Cummings, chief medical officer at Vaxart, said in an investor call reported by Fierce Biotech at the time. “Field efficacy generally goes up, because the amount of inoculum that is causing disease that will be seen in the field is far lower than what is seen in the challenge study. My projection is that we would see an improvement in the decrease of [acute gastroenteritis] with our vaccine.”
Even a slight boost in efficacy could make the vaccine seem worthwhile. A 2012 modeling study suggested that even a vaccine with 50 percent efficacy could avert up to 2.2 million cases and save up to $2 billion over four years.
For now, we’ll have to wait to see what future trial data shows. And Vaxart’s vaccine isn’t the only one in the pipeline, nor is it the furthest along. Moderna has a norovirus vaccine in a Phase 3 trial, which is a larger study that will look at efficacy. But, while the trial is just beginning, Moderna noted in a financial update in February that the trial has been put on hold by the Food and Drug Administration due to a possible neurological side effect in one participant.
“The trial is currently on FDA clinical hold following a single adverse event report of a case of Guillain-Barré syndrome, which is currently under investigation,” Moderna reported. “The Company does not expect an impact on the study’s efficacy readout timeline as enrollment in the Northern Hemisphere has already been completed. The timing of the Phase 3 readout will be dependent on case accruals.”
Beth is Ars Technica’s Senior Health Reporter. Beth has a Ph.D. in microbiology from the University of North Carolina at Chapel Hill and attended the Science Communication program at the University of California, Santa Cruz. She specializes in covering infectious diseases, public health, and microbes.
A small study in Texas suggests that human bird flu cases are being missed on dairy farms where the H5N1 virus has taken off in cows, sparking an unprecedented nationwide outbreak.
The finding adds some data to what many experts have suspected amid the outbreak. But the authors of the study, led by researchers at the University of Texas Medical Branch in Galveston, went further, stating bluntly why the US is failing to fully surveil, let alone contain, a virus with pandemic potential.
“Due to fears that research might damage dairy businesses, studies like this one have been few,” the authors write in the topline summary of their study, which was posted online as a pre-print and had not been peer-reviewed.
The study authors, led by Gregory Gray, were invited to two undisclosed dairy farms in Texas that experienced H5N1 outbreaks in their herds starting in early and late March, respectively. The researchers had a previously approved research protocol to study novel respiratory viruses on dairy farms, easing the ability to quickly begin the work.
Rare study
“Farm A” had 7,200 cows and 180 workers. Illnesses began on March 6, and nearly 5 percent of the herd was estimated to be affected during the outbreak. “Farm B” had 8,200 cows and 45 workers. After illnesses began on March 20, an estimated 14 percent of the herd was affected.
The researchers first visited Farm A on April 3 and Farm B on April 4, collecting swabs and samples at each. Based on the previously approved protocol, they were limited to taking nasal swabs and blood samples from no more than 10 workers per farm. On Farm A, 10 workers provided nasal swabs and blood samples. On Farm B, only seven agreed to give nasal swabs, and four gave blood samples.
While swabs from cows, milk, a dead bird, and a sample of fecal slurry showed signs of H5N1, all of the nasal swabs from the 14 humans were negative. However, when researchers looked for H5N1-targeting antibodies in their blood—an indicator that they were previously infected—two of the 14, about 14 percent, were positive.
Both of the workers with previous infections, a man and a woman, were from Farm A. And both reported having flu-like symptoms. The man worked inside cattle corrals, close to the animals, and he reported having a cough at the time the samples were taken. The woman, meanwhile, worked in the cafeteria on the farm and reported recently recovering from an illness that included fever, cough, and sore throat. She noted that other people on the farm had similar respiratory illnesses around when she did.
The finding suggests human cases of H5N1 are going undetected. Moreover, managing to find evidence of two undetected infections in a sample of just 14 workers suggests it may not be hard to find more. The Centers for Disease Control and Prevention estimates that around 200,000 people work with livestock in the US.
Known infections in humans have all been mild so far. But experts are anxious that with each new infection, the wily H5N1 virus is getting new opportunities to adapt further to humans. If the virus evolves to cause more severe disease and spread from human to human, it could spark another pandemic.
Federal officials are also worried about this potential threat. In a press briefing Tuesday, Nirav Shah, the CDC’s principal deputy director, announced a $5 million effort to vaccinate farm workers—but against seasonal flu.
Shah explained that the CDC is concerned that if farm workers are infected with H5N1 and the seasonal flu at the same time, the viruses could exchange genetic segments—a process called reassortment. This could give rise to the pandemic threat experts are worried about. By vaccinating the workers against the seasonal flu, it could potentially prevent the viruses from comingling in one person, Shah suggested.
The US does have a bird flu-specific vaccine available. But in the briefing, Shah said that the use of that vaccine in farm workers is not planned for now, though there’s still active discussion on the possibility. The lack of severe disease and no documented human-to-human transmission from H5N1 infections both argue against deploying a new vaccine, Shah said. “There has to be a strong and compelling case,” he added. Shah also suggested that the agency expects vaccine uptake to be low among farm workers.
Enlarge/ A vial of the updated 2023-2024 formula of Pfizer’s COVID-19 vaccine at a CVS Pharmacy in Eagle Rock, California, on September 14, 2023.
Staying up to date on COVID-19 vaccines can cut the risk of COVID-related strokes, blood clots, and heart attacks by around 50 percent in people ages 65 years or older and in those with a condition that makes them more vulnerable to those events, according to a new study from the Centers for Disease Control and Prevention.
The finding, published this week in the CDC’s Morbidity and Mortality Weekly Report, should help ease concerns that the shots may conversely increase the risk of those events—collectively called thromboembolic events. In January 2023, the CDC and the Food and Drug Administration jointly reported a preliminary safety signal from their vaccine-monitoring systems that indicated mRNA COVID-19 vaccines may increase the risk of strokes in the 21 days after vaccination of people ages 65 and older. Since that initial report, that signal decreased, becoming statistically insignificant. Other vaccine monitoring systems, including international systems, have not picked up such a signal. Further studies (summarized here) have not produced clear or consistent data pointing to a link to strokes.
In May, the FDA concluded that the evidence does not support any safety concern and reported that “scientists believe factors other than vaccination might have contributed to the initial finding.”
But, the statistical blip could potentially cause lingering concerns. While clinicians had noted lower rates of thromboembolic events among vaccinated people, the authors of the new study noted that, until now, there were no rigorous estimates of how effective COVID-19 vaccines are at preventing those events.
For their analysis, they primarily looked at two groups of patients: A group of 12.7 million Medicare beneficiaries ages 65 and older and a group of around 78,600 Medicare beneficiaries ages 18 and older with end-stage renal disease (ESRD) on dialysis, a condition that increases their risk for thromboembolic events, including COVID-19-related thromboembolic events. Using medical claims records from September 2022 to March 2023, the researchers compared rates of thromboembolic events among the people in those groups that had gotten a bivalent COVID-19 booster dose and those who had only gotten the original monovalent COVID-19 vaccine in the past. To be considered a COVID-related thromboembolic event, the event had to occur within a week of or a month after a COVID-19 diagnosis.
Protective effect
In the group of 12.7 million patients ages 65 and older, about 5.7 million (45 percent) had gotten the bivalent booster, making them up to date on their COVID-19 vaccinations at the time. The remaining 7 million (55 percent) had only gotten the original vaccine.
During the study period, 17,746 patients who were not up to date on their COVID shots got COVID-19 and experienced a COVID-related thromboembolic event. Of the bivalent boosted patients, there were 4,255 COVID-related thromboembolic events. The researchers adjusted for confounding factors, such as age, race, and time of vaccination, and estimated that the bivalent booster was overall 47 percent effective at preventing COVID-related thromboembolic events, which again include strokes, blood clots, and heart attacks.
A sub-analysis including the time since vaccination indicated that the estimated effectiveness waned about two months after receipt of the vaccine, dropping early effectiveness of 54 percent down to 42 percent at 60 days or more.
Among the 78,600 patients ages 18 and up with ESRD, 23,229 (29.5 percent) received a bivalent dose and thus were up to date on their COVID-19 vaccines. The remaining patients (70.5 percent) had only received an original vaccine, and of those, 917 experienced a COVID-19-related thromboembolic event after getting the pandemic virus. Among the up-to-date patients, there were only 123 events. After adjustments, the researchers estimated that the vaccines’ effectiveness against thromboembolic events was 51 percent in this group, which also waned slightly over time.
The study has limitations, such as that it can’t account for previous COVID-19 infections, which could alter people’s risk of developing complications from COVID-19, including thromboembolic events. It relied on medical claims, which have limitations, and it’s possible there are other confounding factors, such as the use of Paxlovid and behavioral differences. Last, Medicare beneficiaries are not representative of the whole population.
But, given the data available, the study authors concluded that it appears the bivalent vaccine dose “helped provide protection against COVID-19–related thromboembolic events compared with more distant receipt of original monovalent doses alone.” The authors recommend that, “to prevent COVID-19–related complications, including thromboembolic events, adults should stay up to date with recommended COVID-19 vaccination.”
