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(CNN) --
The United States is bracing for the possible need to update its COVID-19 vaccines, especially against the omicron variant.
The independent Advisory Committee on Vaccines and Related Biological Products (VRBPAC) of the US Food and Drug Administration (FDA) will meet this Tuesday to discuss whether the composition of Covid-19 vaccines must be modified to target a specific strain of coronavirus and, if so, which strain should be selected.
That means the Covid-19 vaccines people get in the future could be somewhat or completely different formulations than those given now.
Current vaccines are based on the coronavirus that emerged in late 2019, but experts will discuss Tuesday whether they should also target the omicron variant.
At their meeting, VRBPAC members will vote on the question, "Does the committee recommend the inclusion of a SARS-CoV-2 omicron component for COVID-19 booster vaccines in the United States?"
This is a time of transition for the approach to coronavirus vaccines.
Anticipation is growing that vaccinations may be needed annually, similar to how seasonal flu shots are given each year.
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"It is anticipated that we would need a fall booster and what that framework might look like and if a vaccine is needed because of a different variant," Lori Tremmel Freeman, executive director of the National Association of County and City Health Officials, told CNN.
"This becomes a challenge, because is it really a booster if it's not the same formulation? And should we talk about it that way or is it just a new vaccine?" Freeman added.
"We're not talking about how we've gotten flu shot boosters over the years. It's just part of getting a flu shot every year. So this transition is important."
In May, a trio of top FDA officials wrote in the medical journal JAMA that the United States may need to update its Covid-19 vaccines every year and that "a new normal" could include an annual Covid-19 vaccine alongside with a seasonal flu shot.
"By the summer, decisions will need to be made for the 2022-2023 season on who should be eligible for additional booster vaccination and on the composition of the vaccine," wrote Dr. Peter Marks, director of the Center for Biological Evaluation and Research. from the FDA;
Dr. Janet Woodcock, Principal Deputy Commissioner; and FDA Commissioner Dr. Robert Califf.
"Administering additional doses of COVID-19 vaccine to appropriate individuals this fall around the time of the usual influenza vaccination campaign has the potential to protect susceptible individuals against hospitalization and death and thus will be an issue for FDA consideration," they wrote.
"This is going to be... a year of transition," say vaccine experts
FDA vaccine advisers previously met in April to discuss how the composition of Covid-19 vaccines might change to target any new and emerging variants of the coronavirus.
The committee agreed that there should be a framework for how and when such changes take place.
The FDA's Marks called this year a "transition" in how we see the COVID-19 vaccine schedule evolving.
"The hypothesis now is that this is going to be a little bit like the flu. In this 2022-23 season, instead of just getting your flu shot, you're also going to get your Covid-19 booster. And we'll see how that goes," Marks told Bloomberg in an op-ed earlier this month.
"If people getting this booster do well and it looks like we've avoided another big wave from October to March-April of next year, we'll have gotten people used to that," he said.
Children over the age of 5 are already eligible to receive booster doses, and certain immunocompromised individuals and adults over the age of 50 are eligible to receive additional doses of the COVID-19 vaccine.
"We need to start thinking about vaccines where we can adjust the strains once a year and make it more of a flu model instead of saying, okay, every five or four months, you'll get another booster," Marks said in Bloomberg.
"The idea here is that next year we have a campaign, and we don't have to follow it up with another booster campaign. Ultimately, next-generation vaccines would ideally help us sustain throughout the year."
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Pharmaceuticals work on updated vaccines against covid
Original versions of coronavirus vaccines from Pfizer/BioNTech, Moderna and Johnson & Johnson are currently used in the United States, but vaccine makers have been working on updated versions of them.
Moderna has developed a bivalent COVID-19 vaccine booster, called mRNA-1273,214, which the company announced this month has been shown to elicit "potent" immune responses against the BA.4 and BA.5 subvariants of omicron.
This bivalent booster vaccine candidate contains components from both Moderna's original COVID-19 vaccine and a vaccine that targets the omicron variant.
On Saturday, Pfizer and BioNTech said their two booster covid-19 vaccines targeting omicron showed a substantially higher immune response than their current covid-19 vaccine, and preliminary lab studies suggest the vaccines could neutralize omicron BA.4 and BA.5.
Another vaccine manufacturer, Novavax, received support from VRBPAC for emergency use authorization in the United States, but has not yet been authorized by the FDA.
Novavax scientists have also been developing variant-specific updated versions of its Covid-19 vaccine, as well as a combined Covid-19 and flu vaccine.
"Booster adoption so far is not that good"
Public health experts are concerned that there may be slow adoption of any modified Covid-19 vaccine in the future.
"Our booster intake so far is not that good, so another booster won't necessarily make people run out of boosters they've already missed," Freeman said.
About two-thirds of the US population, 67%, are fully vaccinated against Covid-19 with at least their initial series of vaccines, but less than a third, 32%, have received their booster, according to the data. from the CDC, until this Friday.
Vaccination rates for children are still far below other age groups: only 30% of children aged 5 to 11 years and 60% of those aged 12 to 17 years are fully vaccinated, compared to almost 77% of adults.
National data on vaccination rates for children under 5, who became eligible this month, are not likely to be available for a few weeks.
The CDC still considers receiving two doses of Pfizer/BioNTech or Moderna vaccines or a single dose of Johnson & Johnson vaccine to be fully vaccinated.
Any additional dose is called a "booster," and completing all of the recommended boosters of the vaccine is considered to be "up to date."
But that language and messages about completing booster doses, and regarding them as up-to-date rather than part of being fully vaccinated, "isn't working," Dr. Peter Hotez, a vaccine scientist and dean of the School, told CNN. National Tropical Medicine at Baylor College of Medicine.
That is evident in the slow absorption of additional doses.
“Since the beginning of January 2021, I have said that this was always a three-dose vaccine,” he said.
Now, people who have not yet completed their booster doses are becoming more vulnerable to Covid-19 infections, hospitalizations and deaths.
"There are serious consequences because we're starting to see not just major hospitalizations but even major deaths in people who get only two doses of the vaccine and don't get the booster, especially those over 65, so this is more of a discussion. theoretical. Lives are being lost because of the messages," Hotez said.
At the moment, the vaccine-induced protection against covid-19 appears not to last as long as vaccine experts hope, but it is not so clear why.
The decrease in protection could be due to the vaccines themselves or the appearance of coronavirus variants that evade vaccines.
Hotez said he believes the White House should convene a panel of vaccine experts, outside of the FDA's VRBPAC, in a special meeting to determine whether the Covid-19 vaccine technology has a weakness when it comes to durability. and what that means for future vaccine strategies.
"Two things are happening at once. There could be decreased immunity," Hotez said, but at the same time, variants such as delta and omicron have appeared.
"If we only had to worry about the delta (variant), would we have a problem? Or would things have stayed the same? So I don't know the answer to that," Hotez said.
"That's why the experts should be called in."
covid-19 vaccine