Evusheld, the only COVID-19 preexposure prophylaxis treatment with emergency use authorization, may not be effective against subvariant XBB.1.5, which makes up nearly 3 in 10 cases, the FDA said Jan. 6.
The agency is waiting on more data but said it "does not anticipate that Evusheld will neutralize XBB.1.5." The FDA released a similar statement in October when subvariants BQ.1 and BQ.1.1 were dominant, but its emergency use authorization remained while other COVID-19 treatments, such as Eli Lilly's bebtelovimab, were pulled.
AstraZeneca's monoclonal is made up of two antibodies, and it is a preventive treatment administered every six months, according to the CDC.
Here is the reduction in susceptibility against some of the most dominant omicron subvariants, according to the FDA and CDC:
- BQ.1.1 (34.4 percent of cases) — not determined
- XBB (27.6 percent) — not determined
- BQ.1 (21.4 percent) — not determined
- BA.5 (3.7 percent) — 2.8- to 16-fold
- BN.1 (3 percent) — not determined
- BF.7 (2.2 percent) — not determined
- BA.2.75 (1.3 percent) — not determined
As the FDA awaits more information on Evusheld's efficacy, it advised providers to "inform individuals of the increased risk, compared to other variants, for COVID-19 due to SARS-CoV-2 variants not neutralized by Evusheld."