Clinical Trial Info

A Study Looking at the Effectiveness, Immune Response, and Safety of a COVID-19 Vaccine in Adults in the United Kingdom

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This is a study to evaluate the efficacy, immune response, and safety of a coronavirus disease 2019 (COVID-19) vaccine called SARS-CoV-2 rS with Matrix-M1 adjuvant in adults aged 18-84 years in the United Kingdom.

A vaccine causes the body to have an immune response that may help prevent the infection or reduce the severity of symptoms. An adjuvant is something that can make a vaccine work better. This study will look at the protective effect, body's immune response, and safety of SARS-CoV-2 rS with Matrix-M1 adjuvant in the study population.

15,000 Participants in the study will randomly be assigned to receive SARS-CoV-2 rS with Matrix-M1 adjuvant or placebo. Each participant in the study will receive a total of 2 intramuscular injections over the course of the study. Approximately 15,000 participants will take part in the study. The first 400 participants who meet additional criteria will receive a flu vaccine, in addition to the SARS-CoV-2 rS vaccine or placebo, as part of a sub-study.

An effort will be made to enroll a target of at least 25% of participants who are ≥ 65 years of age, as well as prioritizing other groups that are most affected by COVID-19, including racial and ethnic minorities.

The primary endpoint of the U.K. Phase 3 clinical trial is based on the first occurrence of PCR-confirmed symptomatic (mild, moderate or severe) COVID-19 with onset at least 7 days after the second study vaccination in serologically negative (to SARS-CoV-2) adult participants at baseline.

Interim Results

Efficacy was 96.4% (95% CI: 73.8, 99.5) against the original virus strain and 86.3% (95% CI: 71.3, 93.5) against the B.1.1.7/501Y.V1 variant circulating in the U.K (post hoc). The primary efficacy endpoint demonstrated an overall vaccine efficacy of 89.7% (95% CI: 80.2, 94.6). 106 cases were observed, with 10 in the vaccine group and 96 in the placebo group. NVX-CoV2373 was effective against severe disease: five severe1 cases were observed in the study, and all occurred in the placebo group. Four of the five severe cases were attributed to the B.1.1.7/501Y.V1 variant. Fourteen days after dose 1, vaccine efficacy was 83.4% (95% CI: 73.6, 89.5).

In volunteers 65 years of age and older, 10 cases of COVID-19 were observed, with 90% of those cases occurring in the placebo group. Older adults are among the groups most impacted by the disease and are at high risk of complications from COVID-19.