A study, published in preprint on the Medrxiv server, was conducted on people who developed infection with coronavirus despite the vaccine. In these patients the possibility of contagion is clearly reduced, and even if it occurs, the viral load and febrile symptoms are much lower and last less than what happens in those who become infected without being covered by the vaccine.
The anti Covid vaccines it has been discovered through studies are focusing on aspects concerning the relapse for those who have already fallen ill with Covid. The team, led by Mark Thompson of the Centers for Disease Control and Prevention (CDC), surveyed 3,975 health workers and first responders at eight locations in the United States between December 2020 and May 2021. Participants who had an infection from Sars-CoV-2 were 204 (5.1%), of which 16 partially or fully vaccinated and 156 unvaccinated.
Complete vaccination with mRna vaccine works at 91% for not having Sars-CoV-2, while in those who had a dose the effectiveness in preventing contagion dropped to 81%. The mean RNA viral load detected was 2.3 among partially or fully vaccinated participants, compared to 3.8 among the unvaccinated; the analysis showed a 40.2% lower viral RNA load after at least one partial vaccination. Only 25% of people who were vaccinated anyway reported fever compared to 63% of unvaccinated people, with a 58% reduction in the risk of febrile symptoms. Finally, the vaccinated they also reported 6.4 fewer days of discomfort than unvaccinated.