Pfizer, Moderna COVID-19 Vaccines Highly Effective After First Injection In Real World, US Study

(Reuters) – COVID-19 vaccines developed by Pfizer Inc with BioNTech SE and Moderna Inc reduced the risk of infection by 80% two weeks or more after the first of two injections, according to data from a US study in the real world released on Monday.

The risk of infection dropped 90% two weeks after the second shot, according to the study of just under 4,000 vaccinated U.S. health care workers and first responders.

The U.S. Centers for Disease Control and Prevention (CDC) study assessed the ability of vaccines to protect against infections, including infections that did not cause symptoms. Previous clinical trials conducted by the companies have evaluated the effectiveness of their vaccine in preventing illness due to COVID-19.

Results from actual use of these messenger RNA (mRNA) vaccines confirm the efficacy demonstrated in large controlled clinical trials conducted before they received emergency use authorizations from the State Food and Drug Administration. -United.

The study looked at the effectiveness of mRNA vaccines in 3,950 participants in six states over a 13-week period from December 14, 2020 to March 13, 2021.

“Authorized COVID-19 mRNA vaccines have provided early and substantial protection against infection for our country’s healthcare workers, first responders and other essential front-line workers,” said the CDC director, Rochelle Walensky, in a press release.

New mRNA technology is a synthetic form of a naturally occurring chemical messenger used to instruct cells to make proteins that reflect part of the novel coronavirus. This teaches the immune system to recognize and attack the real virus.

The CDC study comes weeks after real data from Israel suggested the Pfizer / BioNTech vaccine was 94% effective in preventing asymptomatic infections.

Some countries, including Britain and Canada, allow prolonged dose gaps that differ from how vaccines have been tested in clinical trials to ease supply constraints. In trials, there was a three-week gap between Pfizer injections and four weeks for the Moderna vaccine.

In Britain, authorities said in January that data supported his decision to increase to 12 weeks between the first and second Pfizer / BioNtech shots. Pfizer and its German partner have warned that they have no evidence to prove it.