Previous Vaccines and Infections Reduce the Chance of Spread of the Omicron Variant – New Scientist

Inmates in California prisons who had been vaccinated or previously infected with the coronavirus were less likely to spread the coronavirus to fellow inmates.

People who have been vaccinated against the coronavirus and also have a previous infection are 41 percent less likely to transmit the virus if they become infected again, compared to people who have not been vaccinated and have not been infected before. People who have only been vaccinated or who have had only a previous infection are also less likely to transmit the virus. This is clear from Research In American prisons, keep track of the number of infections among cellmates during the Omicron wave.

Study suggests that vaccination not only protects against a dangerous course of disease, says sociologist Simon Williams from Swansea University in the United Kingdom. “It’s a very important discovery.”

late spread

Vaccination against coronavirus reduces the risk of hospitalization due to infection. It also reduces the risk of death from Covid-19. But it is still not clear how the vaccine will affect the spread of the virus. This is an important issue, because for some people not only the milder course of the disease, but also the lower chance of it spreading is an important argument for getting vaccinated.

With earlier variants of the coronavirus, it seemed that vaccines had actually slowed the spread. Especially in people who Pfizer / BioNTech . Vaccine There was a big difference: They were 90 percent less likely to pass on their disease. But with the outbreak of the omikron variant in November of last year, it turned out that vaccines mainly protect against a dangerous course of the disease, and less from the rapid spread of the virus.

US prisons

infection doctor Nathan Locke From the University of California, San Francisco, he conducted research in 35 prisons in California. He and his colleagues tested the spread of the Corona virus in prison cells between December of last year and last May.

If a detainee develops symptoms or tests positive, they will not always be immediately isolated. Nearly 1,300 infected inmates shared their cell at least overnight with another person who had previously tested negative.

Detainees who tested negative spent an average of 2.3 days with an infected inmate. More than a quarter of them eventually injured themselves.

If an infected detainee had previously had Covid-19, the chance of spreading was 21 per cent lower than if he had not had a previous infection and had also not been vaccinated. With at least one vaccine but no previous infection, prevalence was 24 percent lower. If the detainee had previously been infected and also received at least one vaccine, the chance of spreading coronavirus was 41 percent lower.

Additionally, with each additional vaccination dose a detainee receives, the chance of spread decreases by 12 percent. The detainees had received three injections at most. “This study underscores how important booster vaccinations are if you want to slow the spread of the virus,” the researchers said.