Labs are developing up-to-date Covid vaccines, but they could come too late

Roseann Renouf, 77, has had enough of the current generation of anti-covid vaccines. After seeing immunized friends contracting Covid-19, she, who says she never liked getting too many shots, decided not to take the latest booster dose, even though she knows they offer important additional protection.

“It would just be taking the same booster again,” said Renouf, a retired nurse in Fort Worth, Texas. “They didn’t do anything different to cover the new variants.”

But your grievance about the vaccines may soon be resolved. Last week, regulatory agencies in the U.S. pledged to update 2020 vaccine recipes for the booster vaccination campaign scheduled for this fall. [no hemisfério norte], with new formulas that aim to defend people against the ultra-contagious subvariants of the omicron. With that, Renouf and other aloof people may have a reason to change their minds.

The Biden administration is betting that the new formulas, which form the centerpiece of an effort to dramatically accelerate vaccine development, could attract the half of vaccinated Americans who rejected booster shots. This sector of the population is a crucial group in the fight against future waves of Covid-19.

According to many scientists, the need for up-to-date vaccines becomes more urgent with each passing day. The most elusive forms of omicron so far, known as BA.4 and BA.5, appear to be driving a new wave of Covid cases across much of the United States. The same subvariants have already led to an increase in hospital admissions in the UK, France, Portugal, Belgium and Israel.

Deaths from Covid-19 in the United States, which for months were close to the lowest levels of the pandemic, have been rising again. Public health researchers predict that, in the worst case scenario, the US could have something like 200,000 Covid-19 deaths in the next 12 months.

“We hope we can convince people to get the booster,” said Dr. Peter Marks, head of the vaccine department at the Food and Drug Administration (FDA), “helping your immune response to mature and helping to prevent another wave of Covid.”

Many scientists consider that updated booster vaccines will be critical to diversifying people’s immune defenses, as subvariants attack the protection offered by vaccines. According to them, it may be impossible to reach a virus that mutates so quickly. But it’s far better to be behind the pathogen just a few months rather than a few years.

“Omicron is so different that it seems pretty clear to me that we’re starting to lose ground in terms of the protection these vaccines provide against symptomatic infections,” said immunologist Deepta Bahattacharya of the University of Arizona. “It is very important to update vaccines.”

The question now is whether the modified boosters will arrive in time. To try to tackle newer forms of the virus, the FDA has asked vaccine manufacturers to adapt their new vaccines to the BA.4 and BA.5 subvariants, not the original version of last winter’s omicron.

Virologists said a vaccine against the subvariants will not only generate the strongest immune defenses against current versions of the virus but also the kind of broad antibody response that will help protect against any form of the virus that emerges in the coming months.

But putting together a vaccine-centric fall booster vaccination campaign at the forefront of the virus’ evolution can come at a cost. Pfizer and Moderna said they will not be able to deliver doses against the subvariants before October. In a public meeting last week, some FDA advisers warned that the schedule could be further delayed due to various routine delays.

In the meantime, a vaccine created specifically against the original version of the omicron will be available sooner: Moderna and Pfizer have already started producing vaccines designed to attack the original form of the omicron, and Moderna has said it could start providing them as early as this summer. [no hemisfério norte]. Whether the benefits of a vaccine that protects especially against the newer subvariants outweigh the disadvantages of having to wait longer will depend on exactly when it hits the market and how much damage the virus does before then, scientists said.

For them, it will be critical that by early autumn some form of an up-to-date vaccine is available.

“I would say that waiting for a vaccine against BA.4 and BA.5 is a good choice, unless it makes the wait for a new booster too long,” said virologist Jesse Bloom of the Fred Hutchinson Cancer Center, in Seattle, speaking out in favor of a vaccine against the subvariants. “If using BA.4 and BA.5 stretches the waiting time for a new vaccine just a little bit, I think it’s a good option.”

The updated vaccines will test the public’s openness to an accelerated vaccination program that has similarities to the way annual flu vaccines are developed, but which is entirely new when it comes to the coronavirus.

The original vaccines had to go through a lengthy and laborious clinical trial process: volunteers took the vaccines and then went about their normal lives, while researchers followed them to see which of them would get sick. Today, however, there is ample evidence that vaccines are safe. And any adaptations to the recipe could be wasted if scientists spend nearly a year testing them.

Instead, vaccine manufacturers have been studying blood samples from volunteers in laboratories to assess their immune response to a booster vaccine adapted to the first version of the omicron. Booster vaccines against the subvariants underwent more summary testing: Pfizer only studied how they affected the antibody responses of mice.

The FDA said it will not require clinical trial data from vaccines against the subvariants before authorizing them; will, instead, be guided by studies on booster vaccines against the original version of the omicron. For some scientists, authorizing the use of modified vaccines without going through lengthy human clinical trials is essential if vaccines are to be made available in a timely manner.

Some scientists advising the government on vaccines say regulatory agencies have yet to prove that updated boosters offer substantially better protection against severe Covid-19 than existing boosters. Others express concern that reformulating vaccines could undermine public confidence in the vaccination program. But for some Americans who hesitate to take the boosters, the fact that the booster shots available today are already out of date is the reason for their disinterest.

“The booster shot probably helps a little, but not so much that it’s worth the trouble of going to get it,” said Cherry Alena, a North Carolina retiree in her 70s, who got her last Covid shot 16 months ago. “It was not formulated specifically to fight the virus that is circulating.”

Alena said she would be interested in a modified vaccine because “it would give specific immunity against the specific variant”.

Gaps in booster coverage left the US more exposed during the omicron waves. More than half of vaccinated Americans did not get a booster dose. Three-quarters of people who are entitled to a second booster dose have not yet taken it.

This spring, four times as many people 50 and older who received just one booster shot died of Covid-19 than people in that age group who received two booster shots, according to the Centers for Disease Control and Prevention (CDC).

When it comes to predicting the evolution of the pathogen, there are no certainties. It is possible that when winter comes, the virus will unexpectedly move away from the omicron branch of the evolutionary tree. And while flu viruses often change over years, variants of the coronavirus can emerge and spread across the world in a matter of months.

But scientists said it was reassuring to know that the updated booster vaccines — which will also contain a component of the original formulation — appear to generate strong immune responses to many versions of the virus. And for now, at least, the signs indicate that this winter’s virus will be a descendant of the omicron.

“The more time that passes, the more likely it is that anything new that emerges will make it out of the micron,” said evolutionary biologist Trevor Bedford of the Fred Hutchinson Cancer Center.

^{Translation by Clara Allain}