The US Food and Drug Administration has set a bar for sponsors to meet in developing COVID-19 vaccines: an efficacy rate of at least 50%. The recommendation is intended to ensure resources are not wasted on a vaccine of limited value and to garner public confidence so people get vaccinated, thereby increasing the likelihood of achieving herd immunity.
The agency set the effectiveness bar in its guidance, "Development and Licensure of Vaccines to Prevent COVID-19," issued on...







