FDA Eyes Second Covid-19 Booster Shot
Agency has begun reviewing data that could lead to clearing a second booster dose of the Pfizer, Moderna vaccines in the fall
U.S. health regulators are looking at potentially authorizing a fourth dose of a Covid-19 vaccine in the fall, according to people familiar with the matter.
The planning is still in early stages, and authorization would depend on ongoing studies establishing that a fourth dose would shore up people’s molecular defenses that waned after their first booster and reduce their risk of symptomatic and severe disease, the people said.
The Food and Drug Administration, however, has begun reviewing data so it can make a decision, the people said.
The thinking among regulators is that the agency would look at authorizing a second booster dose of the messenger RNA vaccines from Pfizer Inc. and partner BioNTech SE and from Moderna Inc., one of the people said.
Among the issues that need to be resolved, the person said, are whether the second booster should be authorized for all adults or particular age groups, and whether it should target the Omicron variant or be formulated differently. Whether the fourth booster could ultimately be the start of an annual Covid-19 vaccination is also under consideration.
No decision is final, and it could be necessary to make booster shots available earlier if a dangerous, elusive variant appears, the person said.
Offering a second booster dose, one of the people said, may make sense in the fall because many people get their annual flu shots then and so might be more receptive to getting vaccinations.
Potential obstacles to the effort are that many people are fatigued with vaccinations after getting initial doses and that others are hesitant to get the shots. About 65% of the U.S. population is fully vaccinated, according to the Centers for Disease Control and Prevention. meaning they have gotten two doses of the vaccine from either Moderna or Pfizer/BioNTech, or one dose of Johnson & Johnson’s shot. About 43% of fully vaccinated people have gotten a booster shot.
Yet a higher percentage of older people and others at higher risk of infection have gotten boosted, and many of them could be eager to get a fourth dose.
After research found that Covid-19 vaccines’ protection sags over time, health authorities began urging people to get a first extra dose. Studies have shown the booster can strengthen immune defenses that have weakened months after initial vaccination.
The Pfizer-BioNTech and Moderna vaccines are two doses, taken a few weeks apart. The CDC recommends third doses of the Pfizer-BioNTech and Moderna at least five months after the second dose.
Researchers have been debating whether a fourth dose is needed, especially to fight highly transmissible variants such as Omicron or new ones that emerge.
Some research suggests that protection from mRNA vaccines after a third dose remains strong overall, but risk of hospitalization increases further out from the dose. In the month after the Omicron variant became dominant in the U.S. around Dec. 20, protection against hospitalization fell from 91% within two months of receiving a third shot to 78% after four months, according to a recent study from the CDC.
In January, Israel’s health ministry published an initial study saying a fourth shot provided threefold protection against serious illness and twofold protection against infection compared with people who were four months after their third shot. Other Israeli researchers who did a separate study cast doubt on whether a fourth shot added effective protection against Omicron.
The Israeli government has cleared use of four doses in certain groups of people, including those who are at least 60 years old, the immunocompromised and healthcare workers.
A fourth booster shot of either the Pfizer or Moderna vaccine could start an annual booster shot campaign, one of the people familiar with the FDA’s planning said.
Some drugmakers already have been expecting booster shots could become a yearly effort. Pfizer CEO Albert Bourla said in a recent interview that the goal shouldn’t be to simply give everyone another dose every few months, although some high-risk people like the immunocompromised or the elderly may need shots every six months.
He said the expectation has been, and remains, that most people, after receiving a three-dose primary series, would need annual shots. Yet Omicron may change thinking, he said, because it is the first variant in which “you see for the first time a significant evasion of protection.”
Pfizer is testing an Omicron-targeting vaccine. An additional dose of such a shot may generate enough protection so that most of the population only needs annual Covid-19 inoculations, Dr. Bourla said.
Among the various parts of Pfizer’s study of the Omicron-targeting vaccine that began last month is one in which people will receive fourth doses of either the current shot or the Omicron one.
Moderna in January started testing an Omicron-specific booster shot in a clinical trial that includes people who have previously received three doses of the original vaccine.