Healthy people should get annual COVID-19 boosters to prevent widespread outbreaks, a new study from Yale University and the University of North Carolina at Charlotte suggests.
Annual shots provide sufficient frequency to prevent large outbreaks without placing an undue burden on the population.
“There appears to be an inflection point at about a year,” said senior author Jeffrey Townsend, a biostatistician and evolutionary biologist at the Yale School of Public Health. “The risk of infection increases exponentially with delay moving from that point.”
Although federal officials suggest annual shots, this study is the first to examine long-term results from a booster schedule and the first to show that boosters spaced more than one year apart will be particularly effective.
The study, published this month, focused on people with healthy immune systems. Townsend and his colleagues are starting work on a similar study looking at the optimal vaccine interval for people with weakened immunity from cancer treatments and other health problems.
What the study found: Annual shots prevent 75% of infections
The researchers modeled antibody levels against the virus that causes COVID-19 if someone was vaccinated with the Pfizer-BioNTech or Moderna vaccine every six months, one year, 18 months, two years or three years over a six-year period. promoted.
The team found that a twice-a-year boost reduced infections by more than 93%, but Townsend said it’s not realistic to ask people to get vaccinated that often.
Annual shots prevented 75% of infections, while waiting six more months reduced the rate of protection to just 55%. The study found that shots every three years prevented just 24% of infections.
“Delaying the administration of the update booster has a negative impact,” it concluded.
Boosters Won’t Prevent All Infections
For healthy people, “the annual increase really does make a difference,” said Alex Dornberg, a bioinformatics expert at the University of North Carolina Charlotte and co-author of the study.
Dornberg said that roughly 3 in 10 people will become infected with COVID-19 even with the annual shot. But without such updates, 9 out of 10 will be infected.
Yale co-author Hayley Hassler said the risk of infection tripled over six years, noting that.
The Centers for Disease Control and Prevention and most infectious disease experts encourage people of all ages to get boosters.
Boosters have to keep evolving too
The virus continues to evolve, “so we need to continually develop Booster and keep it updated to the most prevalent version,” Hassler said.
Townsend said that over time, people will lose the ability to respond effectively to the virus without boosters or reinfection.
The latest booster is directed at both the original coronavirus and BA.4 and BA.5. Although these are no longer the most common versions, the researchers said, the new booster is close enough to provide a benefit.
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getting vaccinated vs getting infected
COVID-19 vaccines have side effects; They can make people feel sad for a day or two. But an infection could be much worse, Dornberg said.
In his own case, he felt terrible for two days after his first round of shots. When he caught COVID-19, however, his lungs hurt for weeks and he had to climb a single flight of stairs.
“It was terrible,” he said. “She calibrated me a little differently.”
Townsend said that contracting COVID-19 provides protection against future infections, but like the vaccine, protection wanes over time.
And it is better not to get infected at all.
“You can’t end up in the hospital for an infection you didn’t get,” Townsend said.
In another study published Wednesday, researchers from the World Health Organization examined 26 earlier papers and concluded that people who get vaccinated or infected do better with severe disease a year later than those who don’t. remain biologically protected, that is, non-vaccination and never get infected.
Studies show that one year after a person is vaccinated and infected, the risk of getting severe COVID-19 or needing hospitalization is reduced by 95%. Someone infected a year earlier but not vaccinated had a 75% lower risk.
Getting infected and getting vaccinated reduces the chance of re-infection by 42% one year later. Someone who was infected but not vaccinated had a 25% lower chance of re-infection.
When will we have better vaccines?
Unfortunately, said Dr. Eric Topol, founder and director of The Scripps Research Translational Institute, the federal government has lost its momentum on vaccine development.
“We need durable vaccines that will last for many years against all variants,” Topol said. “We’re not getting the traction we need on these science projects. The desire, the resources, are not the priority.”
That means that if at some point a worse variant does arise, the US will have to be “reactive rather than doing it all prematurely – and that would be really sad because we know how to outrun the virus and we don’t.” I am doing it,” he said.
Topol believes the nasal vaccine is needed to prevent more infections. Even if the nasal vaccine had to be given more often than the shots, people wouldn’t mind as much.
“I’m excited about it. I haven’t seen anything to rule it out,” he said. “I’d be happy to have a spray every few months to prevent infection.”
Contact Karen Weintraub at [email protected]
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