Mask mandates reduced COVID -19 in two-thirds of states in US

The US Centers for Disease Control and Prevention
have recommended face masks to protect against
COVID-19 practically since the pandemic began, and still
the debate about their efficacy endures. But a new
analysis from Texas Tech University’s Department of
Environmental Toxicology suggests how much of a
difference those face coverings have made.

Published in April 2021 in the International Journal of
Environmental Research and Public Health, the research
analysis by doctoral student James Ayodeji and his
adviser Seshadri Ramkumar, professor of chemical
countermeasures and advanced materials, shows that
roughly two-thirds of states saw a reduction in COVID-19
cases in the three to four weeks after enacting a mask
mandate.

The researchers examined confirmed cases of
COVID-19 from April 1-December 31, 2020, for US states
with and without mask mandates. They analysed the
daily numbers of new cases, cumulative confirmed cases
and infection rates per 100,000 people. After
extrapolating data trends from the 10-20 days before
each state’s mask mandate was enacted, the pair
projected the number of cases that would have been
confirmed at 21 and 28 days after the mandate, had the
trend continued. Then, by subtracting the actual numbers
of cases on those days from their projections, they
determined an approximate number of cases the mask
mandates helped to prevent in each state.

They determined that 63 per cent of the states saw a
reduction in daily and cumulative cases 21 days after the
mandates began, and 66 per cent saw a reduction after
28 days. New York, Iowa and Massachusetts showed the
greatest reductions after their mask mandates went into
effect. New York’s actual number was 111,417 cases
lower than its projection after 21 days, and 160,956
lower than projected after 28 days. Iowa’s actual case
numbers were 49,750 and 69,448 lower, respectively, and
Massachusetts’ 23,816 and 35,104 lower.

Of course, not all states saw such success. California’s
number of actual cases were 74,276 higher than
projected 21 days after its mandate was enacted, and
114,937 higher at 28 days. Michigan’s case numbers were
29,743 and 64,892 higher than projected, respectively.
Texas’ case count was 35,026 higher than projected at 21
days and 41,723 higher at 28 days.

The data shows the potential difference face coverings
can make, the authors noted, but only if mask mandates
are adhered to and masks are worn properly. If not, users
will touch the face more frequently to adjust the fit of the
mask, which can increase the likelihood of transmission.
The communal use of face coverings in conjunction with
other mitigating measures provides maximum protection,
they emphasized.

“Being a material scientist, I never thought that a
material made from cotton and its blends – a face mask
– would have so much global impact in saving lives,” Prof
Ramkumar said. “It makes it clear that to solve global
problems, multidisciplinary research is the need of the
hour.” This work formed a part of a project on Health and
Medical Protection Markets for Cotton funded by Cotton
Incorporated, USA.