COVID-19 vaccine reduces severity, length and viral load in those still infected

http://dx.doi.org/10.1056/NEJMoa2107058

Explanation

An ongoing study from the University of Arizona shows that people who are still infected with COVID-19 after vaccination may have lower viral load, shorter duration of infection, and milder symptoms than those who are not vaccinated.

The COVID-19 vaccine, which is now available, has proven to be very effective in preventing infection, but no vaccine is 100% effective, and cases of infection after vaccination have been reported. In two studies of 3,975 participants, 5 fully vaccinated, 11 partially vaccinated, and 156 unvaccinated participants were found to be infected.

The study found that participants who were partially or fully vaccinated with Pfizer and Modernina messenger RNA vaccines at the time of infection had 40% less virus than those who were not vaccinated. However, while viral load is not an indicator of an individual's contagiousness, early studies suggest that viral load and disease severity and secondary infectivity are affected.

Therefore, in addition to the severity of the participant's illness, the duration of infection has also been investigated. It was found that unvaccinated participants were detected for more than two weeks, compared to about one week for vaccinated participants. This result also means that those who were vaccinated had a 66% reduced risk of being infected for longer than one week. In addition, symptoms with fever were 58% less common in vaccinated participants, and on average, they had two fewer days of illness in bed.