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U.S. Department of Health and Human Services

Update: July 30, 2021

REGEN-COV Authorized by FDA for Post-Exposure Prophylaxis under Emergency Use Authorization

The Assistant Secretary for Preparedness and Response (ASPR) and the Food and Drug Administration (FDA) within the U.S. Department of Health and Human Services are committed to ensuring timely and transparent communication regarding the COVID-19 monoclonal antibody treatments currently authorized for emergency use in certain patients with COVID-19. 

On July 30, 2021, the FDA authorized an additional use for the COVID-19 monoclonal antibody therapeutic REGEN-COV (casirivimab and imdevimab). The REGEN-COV Emergency Use Authorization (EUA) has been expanded to include post-exposure prophylaxis. FDA’s authorization of a therapeutic product for post-exposure prophylaxis is a significant advancement in the COVID-19 response that supplements vaccination for disease prevention.  

The new authorization is for post-exposure prophylaxis use:

  • in adult and pediatric individuals (12 years of age and older weighing at least 40 kg) for post-exposure prophylaxis of COVID-19 in individuals who are at high risk for progression to severe COVID-19, including hospitalization or death, and are:

  • Not fully vaccinated or who are not expected to mount an adequate immune response to complete SARS-CoV-2 vaccination (for example, individuals with immunocompromising conditions including those taking immunosuppressive medications) and
    • Have been exposed to an individual infected with SARS-CoV-2 consistent with close contact criteria per CDC or
    • Who are at high risk of exposure to an individual infected with SARS-CoV-2 because of occurrence of COVID-19 infection in other individuals in the same institutional setting (for example, nursing homes or prisons)

This new authorized use is in addition to the prior authorization of REGEN-COV to treat non-hospitalized patients with mild to moderate COVID-19 in adult and pediatric patients, aged 12 and older, with positive results of direct SARS-CoV-2 viral testing, and who are at high risk for progression to severe COVID‑19, including hospitalization or death. 

REGEN-COV is expected to be effective against circulating variants, including the Delta variant. It should be noted that post-exposure prophylaxis with REGEN-COV is not a substitute for vaccination against COVID-19, and REGEN-COV is not authorized for pre-exposure prophylaxis.

For both non-hospitalized treatment and post-exposure prophylaxis use, the authorized dose is 600 mg of casirivimab and 600 mg of imdevimab. For treatment of mild to moderate COVID-19, a single intravenous infusion is strongly recommended; however, subcutaneous injection may be an alternative if infusion is not feasible or would significantly delay treatment. For post-exposure prophylaxis, REGEN-COV may be administered as either subcutaneous injection or a single IV infusion. Please refer to the updated Fact Sheets for full details about dosing and administration. 

Please contact us at with any questions regarding this update.

  • This page last reviewed: July 30, 2021