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08 July 2021

MRNA vaccines reduce the risk of Covid-19 infection by 91%.

Furthermore, the disease is significantly milder in the rare cases of post-vaccine infection, with reduced severity of Covid-19 symptoms and duration.

The news comes from a new international study, called RECOVER (Research on the Epidemiology of SARS-CoV-2 in Essential Response Personnel), carried out in eight different geographical areas by the Rocky Mountain Center for Occupational and Environmental Health (RMCOEH) of the University of Utah.

The study, published online in the New England Journal of Medicine, builds on preliminary data released by the Centers for Disease Control and Prevention (CDC) in March. The researchers say these results are among the first to show that mRNA vaccination benefits even the very rare cases of post-vaccine infection.



"A peculiarity of this study is that it is among the few to measure the secondary benefits of the vaccine," says Sarang Yoon, DO, co-author of the research. The study was designed to measure the risks and levels of infection among people at the forefront of the pandemic. "We have given these vaccines to some of the highest risk groups: doctors, nurses and first responders," explains Yoon. "These people exposed to the virus day after day were protected by the vaccine. Those who unfortunately contracted Covid-19 despite being vaccinated were still better off than those who didn't."

The study found that mRNA vaccines are 91% effective in reducing the risk of infection with Covid-19 in fully vaccinated people, two weeks after the second dose. In addition, they were found to be 81% effective in reducing the risk of infection after "partial" vaccination, two weeks after the first dose.

The HEROES-RECOVER network recruited 3,975 participants in eight geographic areas. In addition to Salt Lake City, the locations included Miami, Florida; Temple, Texas; Portland, Oregon; Duluth, Minnesota; Phoenix and Tucson and other areas of Arizona. Participants sent samples for Covid-19 testing on a weekly basis for 17 weeks between December 13, 2020 and April 10, 2021. They also reported weekly if they had Covid-19-like symptoms, including fever, shortness of breath, and loss. of taste and smell. Only 204 (5%) of the participants ultimately tested positive for SARS-CoV-2. Of these, 156 were unvaccinated, 32 had unidentifiable vaccination status, and 16 were fully or partially vaccinated.Fully or partially vaccinated participants who developed a relapse had milder symptoms than those who had not been vaccinated.