Health
What to Know About mRNA Vaccines
Health Secretary Robert F. Kennedy, Jr., has repeatedly questioned the safety of mRNA vaccines against Covid-19. Scientists with funding from the National Institutes of Health were advised to scrub their grants of any reference to mRNA. Around the country, state legislatures are considering bills to ban or limit such vaccines, with one describing them as weapons of mass destruction.
While mRNA, or messenger RNA, has received widespread attention in recent years, scientists first discovered it in 1961. They have been studying it and exploring its promise in preventing infectious diseases and treating cancer and rare diseases ever since.
What is mRNA?
A large molecule found in all of our cells, mRNA is used to make every protein that our DNA directs our bodies to build. It does so by carrying information from DNA in the nucleus out to a cell’s protein-making machinery. A single mRNA molecule can be used to make many copies of a protein, but it is naturally programmed to die eventually, said Jeff Coller, a professor of RNA biology and therapeutics at Johns Hopkins University and a co-founder of an RNA therapeutics company.
How do mRNA vaccines work?
Right now, there are three FDA-approved vaccines available that use mRNA, two for Covid-19 and one for R.S.V., or respiratory syncytial virus, in older adults. These vaccines consist of strands of mRNA that code for specific viral proteins.
Say you get a Covid-19 vaccine. The strands of mRNA, packaged into tiny fat particles, go into your muscle and immune cells, said Robert Alexander Wesselhoeft, director of RNA therapeutics at the Gene and Cell Therapy Institute at Mass General Brigham. Protein factories in the cells then take instructions from the mRNA and manufacture a protein like the one found on the surface of a Covid-19 virus. Your body recognizes that protein as foreign, and mounts an immune response.
Most of the mRNA will be gone within a few days, but the body retains a “memory” of it in the form of antibodies, Dr. Coller said. As with other types of vaccines, immunity wanes both over time and as a virus evolves into new variants.
Why are mRNA vaccines being used now?
In the mid-2000s, scientists at the University of Pennsylvania figured out how to get foreign mRNA into human cells without it degrading first. That enabled researchers to develop it for use in vaccines.
The main use for such vaccines right now is to prevent infectious diseases, like Covid-19 and R.S.V., said Dr. Wesselhoeft, who founded a company that develops RNA therapies. The mRNA vaccines can be made very quickly because all of the components, other than the RNA sequence, remain the same across different vaccines.
This feature could be helpful for developing the annual flu vaccine, said Florian Krammer, a virologist at the Icahn School of Medicine at Mount Sinai, who has previously consulted for Pfizer and CureVac on mRNA therapies. Typically, scientists decide in February or March which influenza virus strains to include in a vaccine that will be rolled out in the United States in September. But by that time, a different strain may be dominant. Because an mRNA vaccine can be manufactured more quickly than the current flu shot, scientists could wait until May or June to see which strains are circulating, Dr. Krammer said, increasing the likelihood the vaccine will be effective.
Do these vaccines have risks?
A common question patients ask is whether an mRNA vaccine can affect their DNA, Dr. Boucher said. The answer is no. Our cells cannot convert mRNA into DNA, which means that it can’t be incorporated into our genome.
The vaccine for Covid-19 can cause muscle aches and flulike symptoms, but these are expected side effects for vaccines generally, Dr. Krammer said.
It’s been more than four years since the Covid-19 vaccine was first rolled out “and there are not long-term safety signals,” said Dr. Adam Ratner, a pediatric infectious disease specialist in New York. Many parents were concerned about myocarditis, an inflammation of the heart muscle that was reported as a possible side effect of the vaccine. But, Dr. Ratner said, the risk of such inflammation from an actual Covid-19 infection, or of long Covid or multisystem inflammatory syndrome in children, was far greater.
What else can mRNA be used for?
Vaccines using mRNA are currently being studied for a wide range of diseases, including cancer, cardiovascular disease, autoimmune disorders like Type 1 diabetes and rare diseases like cystic fibrosis, a genetic condition that results in excessively thick, sticky mucus that can plug the airways and damage the lungs.
In cancer, the idea is that the mRNA codes for a tumor protein that the immune system will recognize as foreign, telling the body to attack the tumor. In a genetic disorder like cystic fibrosis, it codes for a functioning version of a deficient protein to replace the faulty one and restore the mucus to healthy state.
A paper in the journal Nature earlier this year showed that an experimental mRNA vaccine for pancreatic cancer provoked an immune response in some patients after they had undergone surgery for the cancer. Patients who experienced that immune response lived longer without cancer than patients who did not.
Another recent paper showed that, in monkeys, an inhaled mRNA therapy could produce a protein needed to form cilia, the hairlike structures that line our airways and move mucus out of them. These proteins malfunction in a debilitating respiratory disorder called primary ciliary dyskinesia.
This research is still in early stages: The pancreatic cancer study, a Phase I trial, included only 16 patients, and there may have been other differences between the two groups that accounted for the different survival times. There is a long history of research showing that interventions may lead to immune responses without actually changing patients’ outcomes, explained Dr. Steven Rosenberg, chief of the surgery branch at the National Cancer Institute and an expert in cancer immunotherapy.
Dr. Richard Boucher, a pulmonologist at the University of North Carolina at Chapel Hill, noted that for lung diseases, it’s extremely difficult to safely get the particles carrying mRNA into exactly the right cells.
In general, Dr. Ratner said, mRNA vaccines are “exciting” in that they offer hope for disease treatments where prior technologies have failed. But mRNA therapy is still a drug technology like any other: In some diseases it likely will work, he said, “and in other cases it probably won’t.”
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No sex for the win? This was the advice given to this year’s NBA champions.
New York Knicks owner James Dolan addressed the now-champs as they headed into the playoffs in April 2026, acknowledging their high potential to eventually win the championship.
“I don’t know if you understand what it would mean for you to win a championship this year … It would be life-changing,” he said. “It will stick with you the rest of your lives, and if you don’t win, you’ll be thinking about it the rest of your lives.”
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As Dolan’s inspirational speech to the team went on, he explained how the next 10 weeks would require each player to make sacrifices – watching their diets, getting proper sleep and perhaps even abstaining from sex.
“You need sacrifice and you need to eliminate all the distractions around you,” he said.
Jalen Brunson of the New York Knicks celebrates with the Bill Russell NBA Finals Most Valuable Player Award trophy and Knicks owner James Dolan after defeating the San Antonio Spurs in Game Five of the 2026 NBA Finals at Frost Bank Center in San Antonio, Texas, on June 13, 2026. (Gregory Shamus/Getty Images)
“I had this idea that maybe you should give up sex for the next 10 weeks,” the owner said. “You don’t have to give up sex for the next 10 weeks – but, like the Spartans … They denied themselves, so that they can have an edge. Get the edge.”
This received a few snickers from the team, and Dolan responded, “Don’t tell [your wives and girlfriends] you’re not going to have sex and don’t tell them it was my idea. But let them know what this is going to be like … and how they’re going to have to sacrifice, too.”
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Dr. Anna Elton, licensed marriage and family therapist and clinical sexologist in Massachusetts, confirmed that this belief has been around for centuries, dating back to the ancients Spartans and early Olympic competitors.
Avoiding sex can preserve energy, increase aggression and sharpen focus, according to Elton.
The theory behind abstaining from sex for better athletic performance supports that it can preserve energy, increase aggression and sharpen focus. (iStock)
But modern research has found little evidence that consensual sexual activity negatively impacts strength, endurance, reaction time or athletic performance when it occurs at least 10 hours before competition, the doctor countered.
However, “activity very close to competition may affect recovery measures,” she added. What may be more important, according to Elton, is the psychological value of abstinence.
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“Choosing to abstain can reinforce discipline and total commitment to a larger goal,” she said. “In those cases, the advantage may come more from mindset and focus than from any physical effect.”
“Whether the sacrifice is alcohol, social activities, favorite foods or sex, the message is often the same: ‘We are all in.’”
New York Knicks guard Jalen Brunson celebrates with teammates after the Knicks defeated the San Antonio Spurs in game five of the 2026 NBA Finals at Frost Bank Center in San Antonio, Texas, on June 13, 2026. (Geoff Burke/Imagn Images)
The science of abstinence
This discussion has historically focused on men, which Elton said is often based on “misconceptions about testosterone and energy depletion.”
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“Research has not demonstrated that normal sexual activity causes a meaningful decline in athletic performance, and concerns about testosterone depletion have not been consistently supported by the evidence,” she said.
“For women, sexual activity may have additional benefits related to stress reduction, emotional regulation and relationship satisfaction.”
Abstaining from sex for athletic performance may create a sense of discipline, minimize distractions, maintain focus on training and reinforce a team culture centered on sacrifice and commitment, experts say. (iStock)
In a separate interview with Fox News Digital, Dr. Anthony Puopolo, a men’s health expert and lead medical provider for RexMD, echoed Elton’s assessment that research largely does not support abstinence as a performance enhancer.
This is despite a small amount of evidence that suggests engaging in sexual activity within two hours of competition could pose a risk to cardiovascular recovery.
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“Unfortunately, nearly all studies (99%) have been conducted in males aged 20 to 40, so there is virtually no data on female athletes, older athletes or diverse populations,” said the Puerto Rico-based expert. “We know what to tell the Knicks, but we are not sure what to recommend for the New York Liberty.”
Importance of connection
Elton said abstinence may still offer psychological benefits for some competitors. “For some athletes, it can become part of a pre-competition ritual that enhances confidence,” she told Fox News Digital.
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Some other potential benefits of sexual activity include stress reduction, improved sleep, mood enhancement, emotional connection with a partner and relief from performance-related tension.
“Strong, supportive relationships are associated with better psychological resilience, which can be valuable during high-pressure competitions,” Elton said.
“One of the most overlooked performance advantages may be having a supportive relationship waiting at home,” a doctor said. (iStock)
“Ultimately, there is no universal rule,” she went on. “What helps one athlete perform at their best may not help another.”
Elton stressed that sleep, recovery, nutrition, stress management and support from loved ones are universal performance boosters.
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“Athletes devote tremendous attention to training their bodies, while overlooking the importance of their personal relationships,” she cautioned. “A supportive partner can be one of the greatest assets during a demanding season.”
“If competition requires temporary sacrifices, make those decisions together and keep communication open.”
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Eliminating sugar from your diet may seem like the key to healthy eating, but research suggests it could have unintended effects on digestive health.
A study presented at ENDO 2026, the Endocrine Society’s annual meeting, suggests that a total lack of sucrose, or table sugar, may harm gut health and disrupt the body’s natural metabolism.
To explore how the total absence of dietary sugar impacts the body, researchers at the Dasman Diabetes Institute in Kuwait City conducted a 16-week study on two groups of mice. Both groups were placed on a low-fat diet, but with one critical difference.
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One group consumed a low-fat diet that included a standard amount of sucrose, while the other group ate a low-fat diet that was completely sugar-free, according to the study’s press release.
Throughout the trial, the scientists monitored a wide variety of physiological factors, including the animals’ weight, glucose tolerance, insulin sensitivity, hormone levels, internal inflammation and the specific composition of their gut bacteria.
A total lack of dietary sugar can cause imbalances in the gut bacteria and lead to signs of fatty liver disease, even without any weight gain, researchers said. (iStock)
The study outcome suggested that completely removing sugar caused several unexpected health problems.
“Completely removing sucrose from a low-fat diet may unexpectedly disrupt gut health and promote inflammation and metabolic dysfunction,” Rasheed Ahmad, principal scientist and head of the Immunology & Microbiology Department at the Dasman Diabetes Institute, said in the release.
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Even though the mice on the sugar-free diet did not gain any extra weight compared to the control group, their internal health indicators deteriorated.
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The animals that lacked sucrose developed an imbalance in their gut microbes and increased inflammation within the intestines and liver.
They also showed signs of poor glucose regulation, insulin resistance and cellular changes associated with fatty liver disease, according to the research.
Future dietary guidelines may shift away from strict, absolute sugar bans and instead focus on overall gut health through balanced nutrition. (iStock)
“The findings suggest that complete removal of sucrose from a low-fat diet may negatively affect gut microbiota and metabolic health,” Ahmad concluded.
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While the risks of high-sugar diets are well-established, the researchers noted that little attention has been given to the effects of completely eliminating sugar from low-fat meals.
Scientists say these new findings highlight that dietary carbohydrates play a valuable role in supporting balance between the immune system and the gut microbiome.
Completely cutting sucrose from a low-fat diet can unexpectedly trigger gut inflammation and disrupt the metabolism, experts say. (iStock)
Because this research was conducted on mice over a relatively short 16-week period, further clinical trials are necessary to determine whether a completely sugar-free diet causes the same gut and liver inflammation in humans.
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Additionally, the study focused specifically on removing sucrose from low-fat meals, meaning the results might not apply to people eliminating sugar while following higher-fat or ketogenic eating plans, the researchers noted.
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The team believes that future dietary guidelines may shift away from strict, absolute sugar restrictions and instead place a greater emphasis on maintaining a diverse, healthy population of gut bacteria through balanced nutrition.
“In the long term, these findings could help improve strategies for preventing and managing metabolic disorders, fatty liver disease and chronic inflammatory conditions,” Ahmad said.
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