The U.S. Food and Drug Administration (FDA) said Thursday that it’s withdrawing emergency use authorization for a Covid-19 drug because it is unlikely to be effective against latest variants circulating within the population.

The drug in query is Evusheld, manufactured by British-Swedish pharmaceutical and biotechnology company, AstraZeneca. It was first authorized in December 2021 as pre-exposure prophylaxis against SARS-COV-2 for immunocompromised individuals as they’re less prone to produce antibodies from vaccination, as per ABCNews.

It’s a kind of monoclonal antibody treatment, containing antibodies which might be produced in a lab that mimic those the body naturally generates when it encounters the virus. It’s a mixture of two antibodies, tixagevimab, and cilgavimab, that bind to the spike protein of the virus that causes COVID-19 and prevents it from entering and infecting cells.

Evusheld doesn’t neutralize several omicron subvariants including BQ.1, BQ.1.1, BF.7, BF.11, BA.5.2.6, BA.4.6, BA.2.75.2, XBB, and XBB.1.5, the FDA said in a press release.

These subvariants are believed to be the explanation for 90% of cases within the U.S., in accordance with the  Centers for Disease Control and Prevention.

“Which means that Evusheld isn’t expected to supply protection against developing COVID-19 if exposed to those variants,” the FDA said within the press release.

“Today’s motion to limit the usage of Evusheld prevents exposing patients to possible unintended effects of Evusheld reminiscent of allergic reactions, which could be potentially serious, at a time when fewer than 10% of circulating variants within the U.S. causing infection are at risk of the product,” the press release continued.

The FDA had previously touched upon this topic. On Jan. 6, the FDA said that it was skeptical that Evusehld would give you the chance to neutralize the XBB.1.5 subvariant “due to its similarity to variants that usually are not neutralized by Evusheld,” the outlet reported.

Meanwhile, AstraZeneca said in a press release that it’s going to proceed to cooperate with the FDA’s decisions.

“AstraZeneca will proceed to work with the FDA and other health authorities to gather, assess and share relevant data regarding Evusheld and SARS-CoV-2 variants,” the statement read. “Evusheld currently stays authorized in other countries where it’s approved for COVID-19 pre-exposure prophylaxis and treatment, including the EU and Japan.”

Despite revoking the emergency use authorization status of the medication, the FDA advised providers of the drug to not discard their products just yet.

“The U.S. Government recommends that facilities and providers with Evusheld retain all product within the event that SARS-CoV-2 variants that are neutralized by Evusheld change into more prevalent within the U.S. in the long run,” the FDA said in its press release.