Distancing Measures Must Continue During Vaccine Roll-Out: Study

January 25, 2021

The vaccine is here, but we still have a long way to go. New research by Jeffrey Shaman and colleagues at Columbia University Mailman School of Public Health and Pfizer finds that millions more Americans will be infected and become ill if policies to enforce physical distancing are lifted prematurely. Results of their study are featured in an article in the New York Times titled “Why Vaccines Alone Will Not End the Pandemic.”

An estimated 29 million additional infections will occur in the United States if current measures are lifted in February compared to a scenario in which they are maintained at least through July, the study finds. Control measures include mask-wearing, remote work where possible, and limited travel.

The researchers used a computer model of the pandemic to estimate that 105 million Americans have already been infected with COVID-19, well above the number of confirmed cases. If current restrictions are kept in place until late July, they project that a total of 158 million Americans will be infected. If measures are eased in mid-March, 6 million additional Americans will be infected. However, if restrictions are strengthened until February, 9 million fewer Americans will be infected. If they are strengthened until July, that number grows to 19 million.

“There are people who are going to want to relax the controls we have in place,” Shaman told the New York Times. “If we start thinking, ‘We’ve got a vaccine, there’s a light at the end of the tunnel, we can stop in a couple of months’ — that’s way too soon.”

The research is based on a pre-print article published in December ahead of peer review. First author Marta Galanti, a post-doctoral researcher; senior author Jeffrey Shaman; and co-authors accounted for factors including the speed and order of vaccine distribution, vaccine effectiveness after one and two doses, current social distancing measures, and virus transmissibility. Their model assumes vaccination will continue at a pace ramping up to 5 million doses per week with a 95 percent effectiveness after two doses. It also assumes that neither those who have recovered from the disease nor those who receive vaccinations could develop an infection or pass the virus on again. The research was supported by Pfizer, the National Science Foundation, and the Morris-Singer Foundation.

The New York Times article quotes several experts who back up the broad strokes of the Columbia findings with caveats that the pace of the vaccine roll-out and virulence of the new virus variant could change the numbers.

The latest findings were published in collaboration with data journalists at the New York Times. Previously, Shaman and members of his team collaborated with the newspaper twice in March of last year and again in May. The March articles were based on the team’s research on the potential impact of the pandemic in the United States and how the virus initially spread outside of China. In May, they estimated that more than 30,000 American deaths could have been averted had distancing measures been put in place one week earlier.