NOT a political thread, but rather a thread for public health facts.
Laura (Layla) H. Kwong, Assistant Professor of Environmental Health Sciences, University of California, Berkeley
Wed, September 22, 2021, 1:55 PM
Recently, I was part of the largest randomized controlled trial to date testing the
. What we found provides gold-standard evidence that confirms previous research: Wearing masks, particularly surgical masks, prevents COVID-19.
People have been
since the
.
During the coronavirus pandemic, the focus has been on masks as a way of preventing infected persons from contaminating the air around them – called source control. Recent laboratory evidence supports this idea. In April 2020, researchers showed that people infected with a coronavirus – but not SARS-CoV-2 – exhaled
. A number of additional
have also supported the efficacy of masks.
Out in the real world, many epidemiologists have
to see if
. One observational study – meaning it was not a controlled study with people wearing or not wearing masks – published in late 2020 looked at demographics, testing, lockdowns and mask-wearing in 196 countries. The researchers found that after controlling for other factors, countries with cultural norms or policies that supported mask-wearing saw weekly per capita coronavirus mortality increase 16% during outbreaks, compared with a
.
