Americans who stayed home before lockdown orders kicked in may have helped save lives, says study
The study, however, suffers from a few limitations, including the fact that it could not differentiate if people stepped out to visit a park, which is a low-risk setting or a high-risk grocery store
Some people may have played key roles in rescuing the country from a more disastrous outbreak. Americans who stayed home, even before the government stay-at-home policies kicked in, could have saved lives, says a study by Johns Hopkins University. With the Covid-19 cases setting new records in the country, researchers recommend that people follow social distancing until a vaccine becomes available.
Researchers relied on mobile data to understand the degree of social distancing. From early March, fewer people moved around, they say. States, on the other hand, issued stay-at-home orders sometime in late March. This reduced mobility may have played a part in bringing down infections in 25 of the worst-hit US counties.
"Our results strongly support the conclusion that social distancing played a crucial role in the reduction of case growth in multiple US counties during March and April, and is, therefore, an effective mitigation policy for Covid-19 in the USA. Critically, we also found that behavioral changes were already underway in many US counties days to weeks before state-level or local-level stay-at-home policies were implemented," Dr. Lauren M. Gardner, Johns Hopkins University, USA, says.
Without this change in behavior, Gardner adds, Covid-19 would have continued its good run for additional weeks in some locations, inevitably resulting in more infections and deaths. "This demonstrates that it is within the power of each US resident to help slow the spread of Covid-19," she adds.
The US reported its first case in January. In four months, the virus spread to every state and more than 90% of all counties. The country had a decentralized response to the Covid-19 threat. Each state enforced varying levels of restrictions, posing challenges for researchers evaluating the effects of social distancing.
Here, the team collected mobile data between January 1 to April 20, 2020, to learn how people moved around before and after the Covid-19 threat emerged. They tested whether a reduced movement coincided with a decline in the infection growth rate in 25 counties. Between January 24 and April 17, 2020, the researchers saw a drop in people's movements: it was 35% lower than normal levels in New York City and 63% in Texas' Harris County.
The data also shows that people erred on the side of caution, despite a mixed political message. These researchers recommend social distancing, along with other behavioral changes such as handwashing, face mask use, and self-isolation when people get sick. "As stay-at-home policies begin to relax, we urge individuals and governments to make safe and data-driven decisions, to respond to the potential risk of increased infections. More timely, consistent, and decisive policy implementation of social distancing and other known effective mitigation measures is urgently needed," co-author Dr. Hamada Badr, Johns Hopkins University, USA, says.
The study suffers from a few limitations, including the fact that it could not differentiate if people stepped out to visit a park, which is a low-risk setting or a high-risk grocery store. The researchers also note that there could be errors in data due to reporting issues and limited Covid-19 testing capacity.
The study is published in The Lancet Infectious Diseases.