This past Thursday, the FDA’s advisory committee on vaccines and similar biological products met to discuss COVID-19 boosters for this fall. They voted in favor of updating the vaccines based on Omicron XBB, a variant lineage that has dominated both in the U.S. and globally this year.
- The fall boosters will be monovalent, meaning they’ll only include the XBB strain—unlike our most recent boosters, which were bivalent (including BA.4/BA.5 and the original, Wuhan strain). The FDA has recommended this switch because research suggests monovalent vaccines may be more effective, and because the original coronavirus strain is no longer circulating; we’re mostly seeing XBB right now.
- The FDA has not yet decided which exact variant will be used for this fall’s boosters. While experts generally agree that it should be an XBB lineage, the FDA will make a final call on this closer to the fall respiratory virus season. XBB.1.5, XBB.1.9, and XBB.1.16 are all major contenders right now.
- This fall’s vaccination campaign is likely to prioritize at-risk populations, including seniors and those with medical conditions that damage their immune systems, similar to the bivalent booster shot rollouts. Ongoing vaccine effectiveness research suggests that these groups benefit most from the protection of an additional booster shot, though people not in these groups obviously benefit as well.
- The CDC will make final decisions about which groups will most need the fall boosters, as well as whether some groups may be eligible for more than one of the shots. Children may also become eligible for new boosters; that’ll be up to the CDC as well.
- In choosing XBB for the fall boosters, the FDA is standardizing with recommendations from the World Health Organization and European Union, which have also suggested that XBB be the target for the next boosters. Last year, the WHO recommended BA.1, while the U.S. used BA.4/BA.5. Standardizing will be helpful for ongoing data collection, since…
- Data problems persist: I’ve written a lot about the U.S.’s disadvantages in tracking vaccine effectiveness, particularly compared to other countries with more standardized health systems. This problem has persisted through all rounds of boosters, including the shots planned for this fall; in fact, it’s even harder now for U.S. agencies to monitor how well the vacines work, as the federal public health emergency’s end led to fewer data collection authorities for the CDC. (Safety monitoring systems will continue, though.)
It’s also worth noting that the boosters this fall will be the first major COVID-19 vaccine rollout following the end of the federal public health emergency. While the Biden administration has devoted some funding for getting vaccines to uninsured Americans, most people will now be getting vaccinated through their health insurance.
This is certain to make the process more complicated and more challenging for many. I’ve already seen stories of people who are eligible for a second bivalent booster having a hard time getting that shot. (See this recent Death Panel episode, for example.) The federal government is doing very little to improve this situation in time for the fall boosters to arrive—and no matter how well XBB vaccines work in theory, they’ll do little in practice if nobody can actually get them.