Government mandates that require people to wear masks in public can slow the spread of Covid-19, a new report published Friday by the Centers for Disease Control and Prevention finds, and communities that don't enact such orders may face dramatic increases in new cases.
The report explored the striking differences among counties in Kansas during the summer: Some adopted mask mandates, while others did not.
In early July, Kansas Gov. Laura Kelly issued an executive order for residents to cover their faces while in public places. Covid-19 cases were surging at the time, especially in the more populated areas of the state.
By Kansas state law, individual counties could opt for less stringent orders. Among the state's 105 counties, 24 adhered to the mask mandate and 81 opted out, the CDC reported.
At the time of the mandate in early July, "Covid-19 incidence had increased 467 percent" in those counties that eventually adhered to the recommendation.
Incidence refers to the "occurrence of new cases of disease or injury in a population over a specified period of time," according to the CDC.
At the time, counties that didn't require masks in public weren't experiencing as much spread of the coronavirus.
Within about six weeks, the rate of Covid-19 spread essentially flip-flopped.
By mid-August, the CDC reported, Covid-19 incidence "decreased by 6 percent" among counties that adhered to the mask mandate. It doubled in counties that did not require face coverings.
"Kansas counties that had mask mandates in place appear to have mitigated the transmission of Covid-19, whereas counties that did not have mask mandates continued to experience increases in cases," the study authors wrote.
Growing evidence shows that masks not only protect others from the spread of the coronavirus, but they also protect the user.
SARS-CoV-2, the virus that causes Covid-19, spreads mainly through respiratory droplets, especially when people are coughing and sneezing.
But even those who are not actively coughing or sneezing can spread the virus through talking, singing or even breathing. The CDC has estimated about 50 percent of transmissions originate from asymptomatic people, or those who have been infected but have not yet developed symptoms.
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While not foolproof, well-fitting masks that cover the nose and mouth can block much of the transmission of those viral particles.
Iowa, New Hampshire and North Dakota recently joined 34 other states in issuing orders to wear masks in public.
Utah Gov. Gary Herbert originally resisted a mask mandate, but within the past few weeks reversed course when the state experienced a surge in cases.
Herbert's latest order, which was applauded by public health groups, ordered residents to mask up "for the foreseeable future."