When the first cases of COVID-19 appeared in Brazil in late February 2020, the twenty-seven Brazilian states responded by implementing a variety of nonpharmaceutical interventions: restrictions on public events, schools, and nonessential commerce, and somewhat later, masking ordinances.
In this study, Louise Russell of the University of Pennsylvania and coauthors estimated the independent effects of seven of these interventions on COVID-19 cases and deaths in twelve Brazilian states, using daily data from March to December 2020.
They found that two interventions-;restrictions on public events and masking mandates-;significantly reduced spread of the disease. Full restrictions on public events reduced the growth rate ratio of COVID-19 cases, which averaged 1.30 before any interventions were introduced, by 0.227. Partial restrictions on public events were equally effective, suggesting that some relaxation was possible without increasing cases.
Full masking mandates were also effective, with a 0.060 growth rate ratio reduction. The authors note that the combined effect of suspending public events and imposing full masking mandates reduced the growth rate ratio to almost 1, the point at which cases are no longer increasing.
Selective use of nonpharmaceutical interventions is important in all countries to minimize the economic and social burdens of controlling COVID-19 but may be especially important in low- and middle-income countries such as Brazil, which have more workers in informal jobs that lack safety-net services, poor infrastructure for distance learning, and less capacity to stimulate their economies.
The authors conclude that their results can help policy makers choose the most effective measures to be adopted when community transmission and incidence of COVID-19 increase.
Russell, L. B., et al. (2022) Effect Of Nonpharmaceutical Interventions On COVID-19 Cases And Deaths In Brazil. Health Affairs. doi.org/10.1377/hlthaff.2021.01613