NIH Releases Statement Regarding AstraZeneca Vaccine

March 23, 2021

The National Institute of Allergy and Infectious Diseases (NIAID) published a news release today regarding AstraZeneca’s COVID-19 vaccine clinical trial, after being notified by the Data and Safety Monitoring Board that outdated information “may have provided an incomplete view of the efficacy data” (1). Which information is outdated has not been specifically disclosed. This statement was released one day after the NIH published a media advisory that the investigational AstraZeneca vaccine prevents COVID-19. 

The placebo-controlled trial included 32,449 adult participants across the US, Chile, and Peru, with approximately 20,000 receiving the vaccine versus 10,000 receiving a placebo. The vaccine was administered as two doses, four weeks apart, and demonstrated 79% efficacy in preventing symptomatic COVID-19. The vaccine showed 100% efficacy in preventing severe symptoms. 

Symptomatic COVID-19 was defined as having a SARS-CoV-2 infection and at least one respiratory symptom, or at least two of the following: loss of taste and/or smell, fever, muscle pain, fatigue, vomiting and/or diarrhea, and cough. Severe symptoms included a SARS-CoV-2 infection and at least one of the following: signs of severe systemic illness, respiratory failure, shock, significant acute renal, hepatic or neurologic dysfunction, ICU admission, and death. 

Similar to Johnson & Johnson’s COVID-19 vaccine, the AstraZeneca vaccine uses an adenovirus to deliver incomplete SARS-CoV-2 genetic material to the body; it does not carry a live SARS-CoV-2 virus. 
AstraZeneca published an update this morning following NIAID’s follow-up statement, stating they will “immediately engage” with the Data and Safety Monitoring Board and share the most up-to-date efficacy data within the next 48 hours (2). Any updated information provided by AstraZeneca will be reviewed by independent advisory committees to ensure accuracy before the FDA and CDC start the authorization process for the use of AstraZeneca’s vaccine in the U.S. It is currently available for use in over 70 countries (3).