In addition, questions about the transmission remain unresolved. Vaccinated people with asymptomatic infections or breakthrough infections may still be able to pass the virus to others, but it is not yet clear how often this occurs.
Until this science is more definitive, or until vaccination rates increase, it’s best to err on the side of safety and regular testing, many experts have said. At the Olympics, for example, frequent testing could help protect the wider Japanese population, who have relatively low vaccination rates, as well as support staff, who may be older and more at risk.
“These are the people that worry me the most, really,” said Dr. Lisa Brosseau, a research consultant at the Center for Infection Disease Research and Policy at the University of Minnesota.
Not only can they contract the virus, adding pressure on the Japanese health system, but they can also become sources of transmission: “Everyone is at risk, and everyone could potentially be infected,” he said. she declared.
According to the Tokyo 2020 press office, all staff and volunteers at the Olympics were given the opportunity to be vaccinated, although officials did not provide data on the number of vaccines.
Instead of testing less frequently, officials could rethink their reaction to positive tests, Dr Binney said. For example, if a vaccinated and asymptomatic person is positive, they still need to be isolated – but maybe close contacts could just be monitored, rather than quarantined.
“You are trying to balance the disruptive nature of what you do when a vaccinated person tests positive against any gain in slowing or stopping the spread of the virus,” Dr Binney said.