- Without interventions, COVID-19 cases would grow at an average of about 38 percent per day, meaning the number of cases would have doubled about every 2 days.
- Some people may mistake the success of this brief period of physical distancing with the end of the first wave.
- Physical distancing, mask wearing, and hygiene habits are good tools to prevent the virus from spreading and overwhelming hospitals.
All data and statistics are based on publicly available data at the time of publication. Some information may be out of date.
Going into lockdown during the COVID-19 pandemic prevented 60 million cases of the virus in America, according to a
Government shutdowns prevented 285 million cases in China, the report found.
“Social distancing works,” said Melissa McPheeters, PhD, MPH, a health policy research professor and co-director of the Center for Improving the Public’s Health Through Informatics at Vanderbilt University Medical Center.
But we need to continue being cautious because the virus is still circulating, McPheeters told Healthline.
Along with other interventions, physical distancing (aka social distancing) and lockdowns were effective in reducing infection rates.
The economic and social costs of shutdown policies was highly visible, but the health benefits in terms of cases prevented or delayed was unseen, said Esther Rolf, a PhD student and one of the study authors from UC Berkeley.
One of the most surprising findings was how high the baseline growth rates of infections were — meaning how quickly the cases would have grown without lockdowns.
Without interventions, COVID-19 cases would grow at an average of about 38 percent per day, meaning the number of cases would have doubled about every 2 days.
“That is a very high baseline growth rate, and it is remarkably consistent across all countries in our sample except Iran,” Rolf said. Because polices were enacted, the growth rate was reduced significantly, she said.
Thomas Glass, PhD, a retired professor of epidemiology at the Johns Hopkins Bloomberg School of Public Health, said that physical distancing can lower the rate of disease transmission.
“All it really does is spread them out over a longer period of time,” he said.
How much contact those with the virus have with people who are susceptible is the most crucial factor in dampening the potential for exponential transmission, like what we saw in April, Glass explained.
“People still are under the false belief that this is a sprint to an end to the epidemic. It’s not. It’s a marathon to herd immunity through the population getting infected or vaccinated,” he said.
“To claim that 60 million infections have been prevented is to miss the point. All we have done is slowed things down to a more manageable pace, which at the moment is 20,000 new cases a day,” Glass pointed out.
While many people talk about a “second wave,” Glass doesn’t like to use the term because it can be confusing for many people.
“Show me the evidence that the first one is over,” he said. “This wave is not over, it’s just shifting terrain, moving from patch to patch.”
Some people may mistake the success of this brief period of physical distancing with the end of the first wave.
“I believe we are now seeing a resurgence of cases as a result of reopening,” Glass said, adding that it will “continue and accelerate.”
He doubts people will adhere to re-engagement of stay-at-home orders if they’re put in place. Although he thinks some will voluntarily stay home.
“It’s going to be a very bumpy summer. And yes, there will be additional wavelets in the fall,” he said. When cold and flu season starts, heat and humidity wane, and people spend more time indoors, there will be a “substantial resurgence.”
“We are nowhere near herd immunity,” Glass said. “Until there is a vaccine, and even after there is, it is likely to be repeated waves of transmission intensity.”
“We need to remain vigilant,” McPheeters said. Physical distancing, mask wearing, and hygiene habits are good tools to prevent the virus from spreading.
“Certainly, it is likely that as we do move toward more familiar operations we will see more cases, and we are already seeing this in a number of states across the country,” she said. This is why strong testing, tracing, and isolation practices are a must.
“As we give the virus more potential hosts, it will try and take advantage,” McPheeters added.
If there is a “second wave,” health systems are prepared to handle it, she said. The country has also learned how to reduce mobility effectively via lockdown measures, and can do so in a targeted way going forward if needed.
“We will need to keep a very close eye on the data and all of the new science we have developed in the past few months, and make sure that information is shared with the public and policymakers,” McPheeters said.
Phase 1 to phase 3 reopening plans recommend that individuals who can stay at home should do so, said Amira Roess, PhD, MPH, a global health and epidemiology professor at George Mason University.
“For as long as the virus is circulating in its current form, individuals are urged to continue to maintain social distance, wear masks in public, monitor their health, and to do their part to reduce the risk of infection to themselves and others,” she told Healthline.
“As the country reopens, we have to remember that we are not yet out of the woods,” Roess added.