The spring lockdown in New York City—once the epicenter of the novel coronavirus in the United States—has been found to have cut transmission of the contagion by about 70%, according to a new study conducted by Columbia University’s Mailman School of Public Health and the New York City Department of Health and Mental Hygiene.
The study, which has yet to be peer-reviewed, can be found on the preprint server medRxiv. The paper noted that widespread use of face masks and coverings during the first month of the outbreak contributed to an additional 7% reduction of new coronavirus cases and 20% among those aged sixty-five and older.
If the city had maintained the same usage rates of masks from April to June, the researchers estimated that they would have helped further reduce transmission by 9% to 11%.
“Improving effective use of face coverings, especially among younger people, would significantly mitigate the risk of a resurgence in COVID-19 infections during re-opening,” senior author Jeffrey Shaman, professor of environmental health sciences at Columbia Mailman School, said in a news release.
“It’s crucial that we find ways to boost consistent and correct mask use in settings where social distancing is not possible.”
The new study’s data are in line with previous modeling efforts, which have estimated that lockdowns were largely responsible for reduced coronavirus transmission by 58% in Wuhan, China, 45% in Italy, and 77% in France.
In New York City, decreasing contact rates among the population was seen as being highly effective across most age groups—contributing to 50% reduction in transmission overall, 51% among children aged one to four, and 83% among those five to fourteen.
“Overall, our study supports the need for multiple interventions, including restricting occupancy to reduce contact rates, universal face covering, testing and contact tracing, and isolation and timing treatment of active infections,” lead author Wan Yang, assistant professor of epidemiology at Columbia Mailman School, said in a news release.
“We need to implement all of those simultaneously in order to effectively mitigate the spread of COVID-19.”
In early March, New York City experienced widespread coronavirus transmission, recording more than 200,000 cases and 21,000 virus-related deaths in the following three months.
Both the state and the city began implementing multiple intervention measures, including public-school closures starting in mid-March, stay-at-home orders for non-essential workers about a week later, and requirements for use of face masks and coverings in public places in mid-April.
Now more than eight months into the pandemic, there are roughly 29.6 million confirmed cases of coronavirus worldwide, including at least 936,000 related deaths, according to the latest data from Johns Hopkins University.
Ethen Kim Lieser is a Minneapolis-based Science and Tech Editor who has held posts at Google, The Korea Herald, Lincoln Journal Star, AsianWeek and Arirang TV. Follow or contact him on LinkedIn. Image: Reuters