The FDA’s Vaccines and Related Biological Products Advisory Committee voted unanimously in support of tweaking the shots to target an XBB strain, as well as dropping the original coronavirus strain from the formulation.
The committee did not, however, make a formal recommendation on which specific XBB lineage the updated boosters should target, nor did it make a recommendation on who should get the shots and when. The latter will likely be left up to the Centers for Disease Control and Prevention, which has its own advisory committee meeting next week.
The recommendation will now be handed off to the FDA, which is expected to make a final decision soon on which Covid strain to target. Drugmakers need enough time to produce and distribute the new shots, which are expected to be used as early as September as part of a fall booster campaign.
Government officials and vaccine manufacturers said data shows targeting an XBB variant will provide better protection than current shots. Targeting more than one variant isn’t necessary, they said, because the current XBB variants are so similar.
It also remains unclear whether healthy people under the age of about 70 or 75 will need regular boosters. Data from several studies suggests that although so-called neutralizing antibodies against the virus fade within four to six months of vaccination, another arm of the immune system, called T cells, continue to provide protection against severe disease.
Since only immunocompromised and older people are at high risk for severe disease if infected, they stand to benefit the most from repeated boosting. But studies do show that several boosters provide more protection than a single shot and that a combination of infection and vaccinations provides even better protection. According to the WHO, about 90% of people worldwide have been infected with SARS-CoV-2, the virus that causes COVID-19.