On Wednesday, the Centers for Disease Control and Prevention (CDC) endorsed a second dose of the updated Covid booster for older adults and individuals with compromised immune systems, aligning with the recent authorization by the Food and Drug Administration (FDA).
According to the FDA’s statement, individuals aged 65 and older can receive a second dose of the revised Pfizer-BioNTech and Moderna Covid boosters at least four months after their last dose.
Most immunocompromised individuals are eligible for an additional dose at least two months after their last dose.
The CDC’s decision followed a meeting of its advisory panel, the Advisory Committee on Immunization Practices, to review the FDA’s updates. With the CDC’s approval, administration of these booster shots can commence immediately.
In addition to endorsing the additional doses, the CDC also recommended moving forward with the bivalent formula for all future Covid vaccines.
This change eliminates the multidose primary series requirement for individuals who have not yet initiated vaccination, streamlining the process to a single dose of the updated vaccine.
The booster shots were redesigned last August to target the BA.4 and BA.5 omicron subvariants alongside the original virus strain.
Although BA.4 and BA.5 are no longer prevalent in the U.S., the dominant strain causing approximately 78% of new Covid cases as of Saturday is the omicron subvariant XBB.1.5, as reported by the CDC.
Dr. Isaac Bogoch, an infectious disease specialist at the University of Toronto, emphasized that despite the booster’s mismatch with the current circulating strain, it still offers considerable protection.
Studies cited by Bogoch and others have indicated that the updated boosters significantly reduce infection risk and hospitalizations, particularly among older adults.
Despite these benefits, booster uptake remains low, with only around 17% of the total U.S. population having received one, according to CDC data.
This week’s decision by the CDC comes after previous deliberations by an FDA advisory committee, which expressed reservations about annual boosters for most adults and children but supported additional doses for high-risk populations, such as older adults and immunocompromised individuals.
Looking ahead, FDA officials plan to convene another advisory session this summer to discuss the strategy for the fall Covid booster campaign, including potential eligibility expansions for younger adults and children.
