According to a source familiar with the consultations, who asked not to be named because they weren’t authorized to share the details, US officials are considering whether to offer people at high risk of severe Covid-19 the opportunity to have a to receive further bivalent refresher of ongoing discussions.
While most Americans are happy to put pandemic precautions – including vaccines – on the back burner, some trying to protect themselves or loved ones from serious illnesses are concerned about how soon they can get another shot.
One of them is Michael Osterholm, who directs the University of Minnesota’s Center for Infectious Disease Research and Prevention.
The 70-year-old quickly got an updated bivalent booster when they launched in the US last fall. The bivalent booster shot is now recommended for all Americans age 5 and older at least two months after their last dose of a vaccine or three months after a Covid-19 infection.
In February, about six months after his previous refresher, Osterholm asked if he could top up his protection with a second bivalent shot, but “I was turned down,” he said.
Studies on the effectiveness of the Covid-19 vaccines show that their protection against infection, emergency room visits and hospitalization decreases after six months when the levels of neutralizing antibodies in the blood fall. Some protection remains in B cells and T cells, components of the immune system that retain memory of past invaders, although the duration of this protection is not fully understood.
Osterholm contracted Covid-19 for the first time last week.
“I have no idea how I caught it,” he said. “I wore N95 [masks]the whole nine yards.”
Osterholm knows that even if he had had a second bivalent booster shot, he might still have gotten sick – the Covid-19 vaccines don’t offer the kind of sterilizing immunity needed to completely block infection – but he can otherwise I wonder if he might have rebounded a little quicker.
“I wonder what it would have been like if I had gotten it,” he said.
As the virus that causes Covid-19 has evolved, it has outsmarted every available type of passive immunity, the antibodies doctors once gave susceptible people to boost their own immune defenses. This makes vaccines one of the few remaining protective measures for people at highest risk of severe Covid-19 infections.
The bivalent vaccines contain two sets of instructions designed to help the body fight off Covid-19. The first shows him how to recognize the defunct ancestral lineage of Covid-19. The second set helps him better recognize and attack the Omicron virus and its descendants.
Data collected by the US Centers for Disease Control and Prevention shows the vaccine update has increased protection.
People who receive the vaccinations are 14 times less likely to die than unvaccinated people and three times less likely than vaccinated people who did not receive the bivalent booster.
A panel of experts who advise the US FDA on its vaccine decisions recommended in January that the agency phase out the monovalent vaccines, which protect only against the ancestral strain, and give Americans who have not yet had their first Covid bivalent doses for the first ones Vaccines to administer -19 vaccines, a group that would mainly include babies and young children.
Although the bivalent vaccines have been helpful, new data suggests that their protection is gradually wearing off, just like the previous boosters.
In the first two months after adults receive the updated booster shot, the shot appears to be about 50% more effective in preventing hospital or emergency room visits for Covid-19, on top of the little protection remaining from previous shots .
After four months, however, the additional protection from bivalent vaccines for the same measures falls to just over 30%, according to data presented at the February meeting of the CDC’s Advisory Committee on Immunization Practices.
Citing this trend, the UK and Canada have begun allowing certain individuals to receive another bivalent booster.
In February, the United Kingdom’s Joint Committee on Vaccination and Immunization recommended that adults aged 75 and over, seniors living in care homes and those over 12 who have suppressed the immune system be offered additional bivalent booster doses at least six months after a previous function .
The Public Health Agency of Canada said adults may be offered an additional bivalent vaccine if they are older, live in a care facility or are over 12 years old and have a medical condition or treatment that affects their immune function.
In fact, US officials are still trying to convince the majority of Americans to get even a first bivalent shot. Only about 54 million Americans – less than 1 in 5 of those eligible – have received a bivalent booster since the government introduced it in September.
The U.S. Food and Drug Administration’s emergency use authorization for the bivalent vaccines does not allow physicians to prescribe another booster shot for at-risk individuals or the CDC to recommend one.
“We continue to closely monitor the new data in the United States and globally and will base any decision on additional updated boosters on this data. Importantly, individuals who have not yet received an updated (bivalent) booster shot are encouraged to speak to their healthcare provider and obtain one,” an FDA spokesman said in an email to CNN.
There are several ways the agency could ease restrictions on the use of the bivalent vaccines.
The first is to fully approve these dual strain shots. On February 24, vaccine maker Pfizer urged the FDA to do so by filing an additional biologics marketing authorization application. Moderna has not announced a similar move and has not responded to a request for comment.
If the FDA grants that request, it will give the CDC the flexibility to change its recommendations for use of the boosters and allow physicians to give another dose to at-risk patients.
Vaccine makers could also ask the FDA to tweak their emergency use authorizations to include so-called permissive language that would allow for a second bivalent dose.
Osterholm said whatever mechanism the FDA uses, he strongly supports giving people the flexibility to get another booster dose if their doctors feel they need it.
Some people eagerly await the chance to get another dose.
“This is absolutely the most frequently asked question right now,” said Dr. William Schaffner, an infectious disease expert at Vanderbilt University. “This part of the population thinks very, very carefully about it.”
In the US, however, he sees no spring boosters on the horizon.
“Neither the FDA nor the CDC’s Advisory Committee on Immunization Practices will make recommendations without data,” Schaffner said. “And no one is now collecting data on another bivalent booster, either in terms of efficacy or safety.”
Other experts think the FDA should make it easier for people who want another bivalent Covid-19 booster to get one.
“One of the disappointments with the mRNA vaccines is that they are not holding up as well as we would like for reasons I don’t think we have fully understand,” said Dr. Peter Hotez, Dean of the National School of Tropical Medicine at Baylor College of Medicine in Houston.
“But that’s the reality and as long as that’s the reality and as long as Covid is still around I think we should be committed to that,” Hotez said, adding that he’d like to see the footage available for adults 50 and over, not the 65 and older group that the FDA is reportedly considering.
“The cans are there and if we don’t use them soon they will have to be disposed of. So it’s better to give them to people who give everything and are willing to take it than just throwing it, right? said Hotez. “So I think the FDA and the CDC will say something pretty soon. That’s my guess, there are enough in the public domain that I think we’ll be hearing from about it pretty soon.”
Others worry that offering more boosters to the elderly and immunocompromised could end up providing a false sense of security but little added protection.
Because aging reduces the body’s ability to respond to vaccines, and because people with compromised immune function also tend not to see a large increase in protection after vaccination, Dr. Yvonne Maldonado, Professor of Global Health and Infectious Diseases at Stanford University, how good a policy change would actually be.
“In this situation, I just don’t know if extra boosters are going to make a difference because we know the immune response for a lot of these people isn’t going to be great,” she said.
On the downside, she says, Covid-19 still hasn’t settled into a predictable pattern that would help public health officials know whether to fire another round of shots at the best time.
“If this were a seasonal virus I would say we are all fine because it would only come out once a year, but we just haven’t developed a real circulation pattern for this virus. So waiting for a fall booster over the next few months is a little risky,” Maldonado said.