The Food and Drug Administration has signed off on the next iteration of covid-19 booster vaccines. On Wednesday, the agency authorized updated versions of the shots developed by Moderna and Pfizer/BioNTech, which are meant to offer better protection against the more-contagious Omicron variants of the coronavirus. Following an expected recommendation from the Centers for Disease Control and Prevention, the vaccines will likely reach the public within weeks.
The upgraded vaccines contain packages of messenger RNA that are designed to induce protection against both the original strain of the coronavirus and the Omicron variants BA.4 and BA.5, which are the most common variants in the world right now. The mRNA tells cells to produce the spike protein of the virus, which then trains the immune system to recognize the whole virus without causing infection. The vaccines are considered bivalent since BA.4 and BA.5 share an identical spike protein, according to the FDA.
“The FDA has been planning for the possibility that the composition of the covid-19 vaccines would need to be modified to address circulating variants,” said Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research in a statement from the agency.
In late July, various media outlets reported that the FDA would abandon plans to immediately authorize a second round of covid-19 boosters for the general public. Instead, the agency would work with vaccine makers Pfizer/BioNTech and Moderna to accelerate the release of their updated booster vaccines. At the time, officials expressed hope that the newer vaccines could be made available as early as September—a timeline that now appears to be right on schedule.
Both the original shots and first round of booster vaccines continue to offer strong protection against severe illness and death from covid-19, but scientists hope that the upgraded boosters will provide greater protection against illness in general and perhaps stem transmission for longer periods of time.
In authorizing the boosters, the FDA relied on safety and immune response data from earlier clinical trials of booster vaccines tweaked to the Omicron BA.1 variant. The agency says that the data should remain relevant even for vaccines that have been upgraded further to protect against newer Omicron variants. And they note that flu vaccines are routinely evaluated in a similar way since they have to be upgraded every year to match the upcoming year’s changes in circulating influenza strains.
“The public can be assured that a great deal of care has been taken by the FDA to ensure that these bivalent covid-19 vaccines meet our rigorous safety, effectiveness and manufacturing quality standards for emergency use authorization,” added Marks.
There are slightly different criteria for eligibility with these upgraded vaccines. Anyone over 12 will be able to get the Pfizer/BioNTech booster shot if it has been at least two months since they were last vaccinated, either with any of the original vaccines or a booster. The Moderna booster has the same timing requirement, but it’s only authorized for those over 18. The single-version boosters are also no longer authorized for people in these age groups, though they can still be used for younger children.
The CDC will have to sign off on its own recommendations for the upgraded boosters, which will almost certainly be a formality. Outside experts assembled by the CDC are scheduled to meet this Thursday to discuss the boosters and a decision from the CDC will likely arrive soon after. The vaccines could be then made available within days or weeks, though they may be initially limited to higher-risk groups, such as health care workers.