The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes the coronavirus disease (COVID-19), is transmitted predominantly by respiratory droplets produced when an infected person coughs, sneezes, sings, speaks, or breathes.
The U.S. Centers for Disease Control and Prevention (CDC) recommends using face masks or face coverings to prevent transmission of SARS-CoV-2. Since October 2020, 33 states and the District of Columbia have imposed statewide mask mandates.
A new study by researchers at the CDC examined whether the implementation of the mask mandate is tied to COVID-19-related hospitalization growth rates among different age groups.
The study, which appeared in CDC's Morbidity and Mortality Weekly Report (MMWR) report, showed that weekly hospitalization growth rates declined by 2.9 percent among adults between the ages of 40 and 64 years old during the first two weeks after the statewide mandate to wear masks.
Several U.S. states required residents to wear masks at all times when they go out of their homes, in retail businesses, and restaurants or food establishments.
The mandate comes after the surging COVID-19 cases in the country, reaching 27.82 million cases. The number of people who have died in the U.S. has reached over 490,000.
In the study, the researchers obtained the cumulative COVID-19-associated hospitalization rates for each week between March 1 and October 17, 2020, from COVID-NET, a population-based surveillance system. The surveillance provides laboratory-confirmed, COVID-19-associated hospitalization rates in 99 counties found in 14 states.
With the decline of hospitalization rates tied to COVID-19, masks may have played an essential role in reducing the virus's transmission.
Masks reduce the emission of virus-laden respiratory droplets. Masks can help reduce the transmission of the virus, not only from infected individuals with symptoms but also from those who are asymptomatic or presymptomatic.
The team also found that the drop in hospitalization growth rates more than three weeks after the face mask mandate was rolled out is consistent with the incubation period of SARS-CoV-2. The median incubation period was about 5.1 days, and most people with symptoms report within 11.5 days after being exposed to the virus. The team believes that more than three weeks of the mask mandate is long enough to determine if efficacy.
"At the individual level, the prevention benefit of using a mask increases as more persons use masks consistently and correctly," the researchers explained.
Previous studies have already validated the benefit of face mask wearing for the control of SARS-CoV-2 spread. The studies showed that after implementing universal masking, new infections significantly decreased.
"This study supports community masking to reduce the transmission of SARS-CoV-2. It also demonstrates that statewide mask mandates were associated with a reduction in COVID-19–associated hospitalization growth rates among adults aged 18–64 years and might affect age groups differently," they added.
Overall, the team reiterated that wearing a mask reduces exposure, transmission, and strain on the health care system.
Apart from wearing face masks, infection control measures should also be emphasized to stem the pandemic, including regular hand hygiene and social distancing.
CDC's double masking
The CDC also recommends that it would be more effective if people use double masks.
On February 10, the CDC released a new study maximizing the effects of wearing masks. The team recommends wearing a cloth mask over a surgical mask.
These mandates are still being evaluated for efficacy. However, it is crucial to know how masks should be worn.
People should wear a mask anytime people are in public settings if they travel, when around people who are not from the same household, or when a family member tests positive for COVID-19.