Covid-19: Lockdowns and masks helped reduce transmission, expert group finds

Non-pharmaceutical interventions (NPIs) were “unequivocally” effective when rolled out in tandem during the covid pandemic and led to “powerful, effective and prolonged reductions in viral transmission,” says a report by a team of experts brought together by the Royal Society.1

The team reviewed thousands of studies undertaken around the world during the pandemic, including randomised controlled trials and observational studies, to assess the effectiveness of six NPIs: face coverings; social distancing and lockdowns; test, trace, and isolate; travel and border restrictions; environmental controls; and communications.

They found “clear evidence” that the strict implementation of NPI packages was effective in reducing the transmission of covid-19 and that these were “most effective” when applied at times of low transmission intensity, showing the importance of early action. However, as the pandemic progressed and the virus became more transmissible these interventions became less effective in controlling transmission, the group found.

Salim Abdool Karim, a Royal Society fellow and member of the working group, told a Science Media Centre briefing, “NPIs work, they …