Dödligt virus från Kina orsakar panik (SARS-CoV-2, COVID-19)

A new CDC study finds the mRNA COVID-19 vaccines authorized by the Food and Drug Administration (Pfizer-BioNTech and Moderna) reduce the risk of infection by 91 percent for fully vaccinated people.

In the new analysis, 3,975 participants completed weekly SARS-CoV-2 testing for 17 consecutive weeks (from December 13, 2020 to April 10, 2021) in eight U.S. locations. Participants self-collected nasal swabs that were laboratory tested for SARS-CoV-2, which is the virus that causes COVID-19. If the tests came back positive, the specimens were further tested to determine the amount of detectable virus in the nose (i.e., viral load) and the number of days that participants tested positive (i.e., viral shedding)

To determine whether COVID-19 illness was milder, study participants who became infected with SARS-CoV-2 were combined into a single group and compared to unvaccinated, infected participants. Several findings indicated that those who became infected after being fully or partially vaccinated were more likely to have a milder and shorter illness compared to those who were unvaccinated. For example, fully or partially vaccinated people who developed COVID-19 spent on average six fewer total days sick and two fewer days sick in bed. They also had about a 60 percent lower risk of developing symptoms, like fever or chills, compared to those who were unvaccinated. Some study participants infected with SARS-CoV-2 did not develop symptoms.

Other study findings suggest that fully or partially vaccinated people who got COVID-19 might be less likely to spread the virus to others. For example, fully or partially vaccinated study participants had 40 percent less detectable virus in their nose (i.e., a lower viral load), and the virus was detected for six fewer days (i.e., viral shedding) compared to those who were unvaccinated when infected. In addition, people who were partially or fully vaccinated were 66 percent less likely to test positive for SARS-CoV-2 infection for more than one week compared to those who were unvaccinated. While these indicators are not a direct measure of a person’s ability to spread the virus, they have been correlated with reduced spread of other viruses, such as varicella and influenza.