According to a study published in the journal Nature Medicine, booster shots helped limit the transmission of omicron variants during the first wave. The study conducted by researchers from the University of California showed that the likelihood of viral transmission fell by 11% for each additional dose.

In the study, the researchers analyzed data collected from the California Department of Corrections and Rehabilitation (CDCR). The collected data showed that in the duration of 5 months, 22,334 inmates contracted SARS-CoV-2 Omicron infections, and 31 inmates were hospitalized. The researchers observed that the vaccinated residents were 28% less likely to transmit the COVID infection in comparison to 38% of the unvaccinated residents.

The study, however, found that the likelihood of transmission increased by 6% every five weeks since the last vaccine shot. Also, inmates with hybrid immunity acquired from both infection and vaccination were 40% less likely to transmit the virus. 

(Source: https://www.daijiworld.com/news/newsDisplay?newsID=1035962 )