Evusheld (Tixagevimab/Cilgavimab): COVID-19 Pre-Exposure Prophylaxis for High-Risk Individuals

Evusheld is a combination of two long-acting monoclonal antibodies (tixagevimab and cilgavimab) authorized for pre-exposure prophylaxis of COVID-19 in high-risk individuals. It is administered as two consecutive intramuscular injections and is not a vaccine—it provides passive immunity by delivering ready-made antibodies.

Who Was Eligible? (Historical Context)

Important: As of early 2023, the FDA revoked Evusheld's Emergency Use Authorization because it was no longer effective against circulating Omicron subvariants (particularly XBB.1.5 and later). The information below reflects its authorized use during 2022–early 2023.

It was authorized for individuals aged 12+ (≥40 kg) who:

• Are moderately to severely immunocompromised and unlikely to mount an adequate immune response to COVID-19 vaccination, OR
• Have a history of severe adverse reactions to COVID-19 vaccines or their components, making vaccination contraindicated.

Effectiveness (During Authorization Period)

Clinical trials (PROVENT) showed Evusheld reduced the risk of symptomatic COVID-19 by approximately 77% in immunocompromised participants and 83% in high-risk individuals over 6 months.

Side Effects

Most common: injection site reactions (pain, redness, swelling, bruising). Less common: headache, fatigue, myalgia, fever. Rare but serious: hypersensitivity reactions (including anaphylaxis), cardiac events (observed in trial imbalance, causality unclear).

Duration of Protection

Expected to provide protection for approximately 6 months, with repeat dosing recommended every 6 months for ongoing prophylaxis. Actual duration varied individually.

Current Status

Evusheld is no longer authorized for use in the U.S. due to lack of activity against dominant variants. Immunocompromised individuals should discuss current prophylaxis options (e.g., pemivibart/Pemgarda, authorized March 2024) and treatment plans with their healthcare providers.