SAN DIEGO (KGTV) — From business closures to limits on gatherings, there’s mounting evidence that government restrictions do slow the spread of COVID-19. But which policies are the most effective?
A study published this month in the journal Science aims to answer that question by examining data from 41 countries outside the U.S.
The researchers examined seven kinds of COVID-19 policies in mostly European countries and compared them to case and death rates in those countries over time.
The policies included limiting gatherings to 1000 people or less, to 100 people or less, and to 10 people or less; a targeted closure on high-risk businesses; a broad closure of most non-essential businesses; school and university closures; and stay-at-home orders.
The authors found limiting gatherings to 10 people or less was the most effective nonpharmaceutical intervention of the seven examined, reducing the transmission rate by 42 percent.
Closing schools and universities was next, cutting transmission by 38 percent. The researchers said they were not able to examine the relative importance of closing universities over grade schools because such closures were typically implemented at the same time.
Next, the researchers examined the impact of two kinds of business closures. They found broad closures of most non-essential businesses were “only somewhat more effective than targeted closures” of high-risk businesses like restaurants, bars and nightclubs. Broad business closures reduced transmission by 27 percent compared to an 18 percent reduction for targeted closures.
“Therefore, targeted business closures can be a promising policy option in some circumstances,” the authors wrote.
The study estimates those three policies together -- closing high-risk businesses, closing schools and universities, and limiting gatherings to no more than 10 people -- are enough lower to slow the spread of the virus.
In epidemiological terms, interventions are considered successful when they lower the so-called number below 1. The reproduction number, or R number, is the average number of people who become infected from one infectious person. Without interventions, the study found the R number for COVID-19 between January and May was 3.3.
The study did not examine the impact of wearing masks, but other studies have found that masks can also significantly reduce the spread of COVID-19.
So what about stay-at-home orders? Mandatory stay-at-home orders where people are only allowed outside for essential tasks or during certain times of the day tend to be a last resort, when there are other restrictions already in place.
The researchers found mandatory stay-at-home orders cut transmission another 13 percent on top of other policies. “Issuing a stay-at-home order had a small effect when a country had already closed educational institutions, closed nonessential businesses, and banned gatherings,” the authors wrote.