Study : Moderna, Pfizer prove to be highly effective after first dose
Covid19 vaccines developed by Pfizer Inc with BioNTech SE and Moderna Inc reduced risk of infection by 80% two weeks or more after the first of two shots, according to data from a real-world U.S. study.
The risk of infection fell 90% by two weeks after the second shot, the study of nearly 4,000 U.S. healthcare personnel and first responders found. The study by the US Centers for Disease Control and Prevention (CDC) evaluated the vaccines’ ability to protect against infection, including infections that did not cause symptoms. Previous clinical trials by the companies evaluated their vaccine’s efficacy in preventing illness from Covid-19.
The study looked at the effectiveness of the mRNA vaccines among 3,950 participants in six states over a 13-week period from Dec. 14, 2020 to March 13, 2021. About 74% had at least one shot, and tests were conducted weekly to catch any infections without symptoms.
The new mRNA technology is a synthetic form of a natural chemical messenger being used to instruct cells to make proteins that mirror part of the novel coronavirus. That teaches the immune system to recognize and attack the actual virus.