FDA advisers to consider whether Omicron-specific coronavirus vaccines are needed
The United States is preparing for the possible need to update its Covid-19 vaccines.
The US Food and Drug Administration’s independent Vaccines and Related Biological Products Advisory Committee is set to meet Tuesday to discuss whether the composition of Covid-19 vaccines should be modified to target a specific coronavirus strain, and if so, which strain should be selected.
That means the Covid-19 vaccinations that people receive in the future could be somewhat or completely different formulations than what are administered now. The current vaccines are based on the coronavirus that emerged in late 2019, but the experts will discuss Tuesday if vaccines should also target the Omicron variant.
In their meeting, VRBPAC members will vote on the question: “Does the committee recommend inclusion of a SARS-CoV-2 Omicron component for COVID-19 booster vaccines in the United States?”
This is a moment of transition for the approach to the coronavirus vaccines. Anticipation is mounting that vaccinations could be needed annually – similar to how seasonal flu shots are administered each year.
“There’s anticipation that we would need a fall booster and what that framework would look like and if a vaccine is needed due to a different variant,” Lori Tremmel Freeman, chief executive officer of the National Association of County and City Health Officials, told CNN.
“This becomes challenging, because is it really a booster if it’s not the same formulation? And should we be talking about it in that way or is it simply a new vaccination?” Freeman added. “We don’t discuss that we have received boosters of flu shots over the years. It’s just part of getting your flu shot every year. So this transition is an important one.”
In May, a trio of top FDA officials wrote in the medical journal JAMA that the United States might need to update its Covid-19 vaccines each year and “a new normal” may include an annual Covid-19 vaccine alongside a seasonal flu shot.
“By summer, decisions will need to be made for the 2022-2023 season about who should be eligible for vaccination with additional boosters and regarding vaccine composition,” wrote Dr. Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research; Principal Deputy Commissioner Dr. Janet Woodcock; and FDA Commissioner Dr. Robert Califf.
“Administering additional COVID-19 vaccine doses to appropriate individuals this fall around the time of the usual influenza vaccine campaign has the potential to protect susceptible individuals against hospitalization and death, and therefore will be a topic for FDA consideration,” they wrote.
The FDA’s vaccine advisers previously met in April to discuss how the composition of Covid-19 vaccines could change to target any new and emerging coronavirus variants. The committee agreed that there needs to be a framework for how and when such changes take place.
FDA’s Marks has called this year a “transitional” one in how we view the evolving Covid-19 vaccine schedule.
“The hypothesis now is that this is going to look somewhat like influenza. In this 2022-23 season, instead of just getting vaccinated against influenza, you’ll also get your booster for Covid-19. And we’ll see how that goes,” Marks told Bloomberg in an opinion article earlier this month.
“If people who get that boost do well and we seem to have avoided another big wave from October to March-April of next year, we will have gotten people used to that,” he said.
People age 5 and older are already eligible for booster doses, and certain immunocompromised people and adults 50 and older are eligible for additional doses of Covid-19 vaccine.
“We have to start thinking about vaccines that we can adjust strains of once a year and make it more of a flu model rather than saying, OK, every five months or four months, you’ll get another booster,” Marks told Bloomberg. “The idea here is that next year we have one campaign, and we don’t have to follow it up with another booster campaign. Ultimately, next-generation vaccines would ideally help hold us for that full year.”
Currently, the original versions of the Pfizer/BioNTech, Moderna and Johnson & Johnson coronavirus vaccines are used in the United States – but vaccine makers have been working on updated versions of their vaccines.
Moderna has developed a bivalent Covid-19 vaccine booster, named mRNA-1273.214, which the company announced this month has been shown to elicit “potent” immune responses against the Omicron subvariants BA.4 and BA.5. This bivalent booster vaccine candidate contains components of both Moderna’s original Covid-19 vaccine and a vaccine that targets the Omicron variant. T
On Saturday, Pfizer and BioNTech said their two Covid-19 vaccine boosters targeting Omicron showed a substantially higher immune response than its current Covid-19 vaccine, and preliminary lab studies suggest the vaccines could neutralize the Omicron BA.4 and BA.5.
Another vaccine maker, Novavax, has received VRBPAC’s support for emergency use authorization in the United States, but has not not yet been authorized by the FDA. Novavax scientists also have been developing variant-specific updated versions of their Covid-19 vaccine as well as a Covid-19 and flu combination vaccine.
Public health experts worry that there might be a sluggish uptake of any modified Covid-19 vaccines in the future.
“Our booster uptake so far isn’t that great, and so another booster is not going to necessarily cause people to run out and get the boosters they’ve already missed,” Freeman said.
About two-thirds of the US population – 67% – is fully vaccinated against Covid-19 with at least their initial series of vaccine, but less than a third – 32% – have received their booster, according to data from the CDC, as of Friday.
Vaccination rates for children still lag far behind other age groups – just 30% of children ages 5 to 11 and 60% of those ages 12 to 17 are fully vaccinated, compared with nearly 77% of adults. National data on vaccination rates for children under 5, who became eligible this month, will likely not be available for a few weeks.
The CDC still considers receiving two doses of the Pfizer/BioNTech or Moderna vaccines or a single dose of the Johnson & Johnson vaccine as being fully vaccinated. Any additional doses are called “boosters,” and completing all recommended boosters of vaccine is considered being “up to date.”
But that language and messaging around completing booster doses – and considering them as being up to date instead of as part of being fully vaccinated – “is not working,” said Dr. Peter Hotez, vaccine scientist and dean of the National School of Tropical Medicine at Baylor College of Medicine, told CNN. That is evident in the slow uptake of additional doses.
“Since the beginning of January 2021, I’ve said 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’s heavy consequences because we’re starting to see not only breakthrough hospitalizations, but even breakthrough deaths in people getting only two doses of the vaccine and not getting the booster – especially those over the age of 65 – so this is more than a theoretical discussion. Lives are being lost because of the messaging,” Hotez said.
At the moment, vaccine-induced protection against Covid-19 seems to not stay durable for as long as vaccine experts would hope, but it is not so clear why. Waning protection could be due to the vaccines themselves or due to the emergence of coronavirus variants evading the vaccines.
Hotez said that he thinks the White House should convene a panel of vaccine experts – outside of 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.
“There’s two things happening at once. There could be waning immunity,” Hotez said, but at the same time, there have been variants like Delta and Omicron arriving on the scene.
“If all we had to worry about was Delta, would we be having a problem? Or would things have held up? And so I don’t know the answer to that,” Hotez said. “That’s why you want to convene the experts.”