Prevention of COVID-19

One main study involving over 5,000 people showed that Evusheld reduced the risk of COVID-19 infection by 77%, with duration of protection from the virus estimated to be at least six months. In the study, adults who had never had COVID-19 and had not received a COVID-19 vaccine or other preventative treatment received Evusheld or placebo (a dummy injection). Of the people given Evusheld, 0.2% (8 out of 3,441) had lab-confirmed breakthrough COVID-19, compared with 1% (17 out of 1,731) of the people who received placebo.

The study data were collected before the emergence of the Omicron variant. Laboratory studies show that the Omicron BA.1 variant may be less sensitive to tixagevimab and cilgavimab at 150 mg doses than the Omicron BA.2 variant.

Treatment of COVID-19

A main study involving around 900 adults with COVID-19 who did not need oxygen and who were at increased risk of their illness becoming severe showed that Evusheld led to fewer cases of severe COVID-19 or death than placebo. Of the patients who were not hospitalised at the time of treatment, 4.4% (18 out of 407) treated with Evusheld developed severe COVID-19 or died within 29 days of treatment, compared with 8.9% (37 out of 415) of those receiving placebo.  

No clinical data were collected on the latest variants of concern, including Omicron sub-variants.