Nature: COVID vaccines cut the risk of transmitting Delta — but not for long

According to the study conducted by Marm Kilpatrick, an infectious disease researcher at the University of California, Santa Cruz, people who become infected with the Delta variant are less likely to transmit the virus to their close contacts if they have had a COVID-19 vaccine. This latest study examined the effects of vaccines on transmission rates by analyzing testing data from 139,164 close contacts of 95,716 people infected with SARS-CoV-2 between January and August 2021 in the United Kingdom, when the Alpha and Delta variants were competing for dominance. The problem with the Delta variant, however, is that the vaccine’s beneficial effect seems to wane to almost negligible levels over time. It was estimated that for people infected with the vaccine developed by the University of Oxford and AstraZeneca, the chance that an unvaccinated close contact would test positive was 57%, but 3 months later, that chance rose to 67%. With booster shots becoming more and more available every month, there is hope to dampen the effects of the Delta variant. Read the full article here