The only way to accurately compare the effectiveness of medical products, such as vaccines or drugs, is by direct comparison in head-to-head clinical trials, which did not happen for these vaccines. For primary and booster vaccination, people should receive an age-appropriate mRNA vaccine (Pfizer or Moderna). The Johnson & Johnson vaccine is authorized for anyone age 18 and older if no other approved vaccine is available because of the risk of a rare but serious blood clotting disorder. CDC said that receiving any vaccine is better than being unvaccinated, and the public will continue to have access to Johnson & Johnson’s COVID-19 vaccine. If you would like to receive the Johnson & Johnson vaccine. please discuss the risks and benefits with your healthcare provider or the healthcare professional at your vaccination site.
All of the COVID-19 vaccines that the U.S. FDA has authorized for emergency use were at least 50% more effective than placebo in preventing COVID-19, consistent with FDA recommendations provided in our October 2020 guidance document, Emergency Use Authorization for Vaccines to Prevent COVID-19. A vaccine with at least 50% efficacy would have a significant impact on disease, both at the individual and community level.