Pfizer and BioNTech announced Tuesday that they are seeking emergency authorization for a second dose of their Covid-19 booster shot for older Americans.
The companies say the fourth shot could bolster immunity for Americans 65 and older, especially as new variants—like Omicron's BA.2 subvariant—emerge. The request to the Food and Drug Administration (FDA) is spurred by increasing evidence that protection from three shots has waned over time, according to NPR’s Scott Hensley.
“The protection that you are getting from the third, it is good enough, actually quite good for hospitalizations and deaths,” says Pfizer’s chief executive, Albert Bourla, on CBS’s “Face the Nation” on Sunday. “It’s not that good against infections.”
Before submitting a request for a second Covid-19 booster, the company looked at two real-world data sets from Israel, where second booster shots have been more widely available. One of the studies reviewed the health records of over one million people and concluded that those who got a second booster were less likely to become infected with the virus and fall seriously ill than those who had received just one booster, Sharon LaFraniere reports for the New York Times.
The second study, which looked at health care workers in Israel, found that individuals who got the fourth shot of either Pfizer’s or Moderna’s vaccine saw a jump in antibody levels, but the additional jab wasn't very effective at decreasing infections.
“The submission is based on two real-world data sets from Israel analyzed at a time when the Omicron variant was widely circulating,” Pfizer says in a press release. “These data showed evidence that an additional mRNA booster increases immunogenicity and lowers rates of confirmed infections and severe illness.”
The emergency authorization request has already reignited a debate among public health officials over when additional doses should be recommended for Americans. Some scientists stress that Pfizer’s current vaccination schedule still provides strong protection for most people against getting very sick, especially for young and healthy people. Others worry the rush to supply a fourth shot for people 65 and older could come at the expense of those getting an initial vaccination series.
A panel of advisors to the FDA is expected to meet next month to discuss the potential of a fourth jab. They may also discuss whether the booster should be the same formula as the current vaccines, or tweaked to counter specific variants, per reporters for the Washington Post.
Currently, a fourth shot of the vaccine is already authorized for Americans who have moderately or severely compromised immune systems. According to the Centers for Disease Control and Prevention, around 65 percent of the United States population is fully vaccinated, but only half of those eligible for boosters have received them.