The evidence is clear that masks cut down on COVID-19 deaths, but nearly a year and a half into the pandemic and with vaccination coverage climbing in many places, public-health scientists and officials are still struggling to get people — particularly unvaccinated people — to wear masks at appropriate times.
Average mask use across the United States has been declining since mid-February. Meanwhile, infection rates in some places have increased. A patchwork of policies and mixed messages from both politicians and public-health officials has resulted in confusion, consternation and a mess of data to interpret.
In a [study], published this January, researchers found that a national mandate for employees to wear face masks early in the pandemic could have reduced the weekly growth rate of cases and deaths by more than 10 percentage points in late April 2020. The study suggests that this could have reduced deaths by as much as 47% (or by nearly 50,000) across the country by the end of May last year. Another preprint, published in October, linked mask mandates with a 20–22% weekly reduction in COVID-19 cases in Canada.
Still, the debate over the effectiveness of masks, and whether or not they continue to be necessary, trundles on.