Drs. Terence Dermody and Mark Gladwin: On covid-19, we need to keep at it

The covid-19 pandemic continues to rage, with rates of new infections increasing in many parts of the country, including in Western Pennsylvania. In Allegheny County alone, almost 15,000 people, or just over 1.2% of the county’s population, have tested positive for SARS-CoV-2, the coronavirus that causes covid-19, and over 400 have died. The frail elderly and persons from communities of color have been disproportionately affected, and most of us now know someone who has been infected.

The pandemic has touched virtually every sector of the economy, and some industries may take years to recover. We all worry about the covid-19-induced challenges to education at every level and the untoward effects of the pandemic on our behavioral and physical health. This is really tough.

What is the way forward? Surely not herd immunity. This concept suggests that if enough of us become infected with SARS-CoV-2, then the resultant immunity in the population will deprive the virus of susceptible hosts and drive it into extinction.

There are three problems with this idea.

First, although the virus has been circulating in the United States for over eight months, less than 3% of the population has been infected. Unfortunately, most experts think that at least 60-70% of the population needs to be immune to confer protection for the entire herd against a virus like SARS-CoV-2. Even if the overall infection rates are higher than documented, it will take years for enough of us to become infected to achieve herd immunity.

Second, no one knows how long SARS-CoV-2 immunity will last. There are now several documented cases of SARS-CoV-2 reinfection, albeit rare, demonstrating that immunity can wane. If we use the example of other coronaviruses, immunity to SARS-CoV-2 may last only a few years. Therefore, by the time enough people have been infected to theoretically achieve herd immunity, those infected early in the pandemic may be susceptible again, and herd immunity will not be achieved.

Third, and most importantly, ongoing infection on the scale to achieve herd immunity will lead to unprecedented human suffering, even more than we have already experienced. Our hospitals will be overwhelmed caring for the sick, schools will not be able to safely reopen, the economy will remain shuttered, and many of our friends, neighbors, co-workers and family members will die.

But the situation is not dire. We do have a way forward. All available evidence indicates that masking, physical distancing, hand-washing and staying away from others when ill dramatically decrease the transmission of SARS-CoV-2 and limit covid-19.

Most of our current cases can be traced to a failure to follow these precautions. Masking, in particular, is most important. We think masks should be considered part of our clothing. We don’t leave our homes without wearing clothes, and we shouldn’t leave our homes without wearing masks.

The covid-19 precautions can be bothersome at times, but until we have safe and effective antiviral countermeasures and vaccines, they represent our best option to protect the most vulnerable, get our children back to school, and return to a semblance of life before the covid-19 pandemic.

So keep at it, Pittsburgh. Mask up and drive the covid-19 numbers down.

Dr. Terence Dermody is the Vira I. Heinz Distinguished Professor and chair of the Department of Pediatrics, University of Pittsburgh School of Medicine, and physician-in-chief and scientific director, UPMC Children’s Hospital of Pittsburgh. Dr. Mark Gladwin is the Jack D. Myers Distinguished Professor and chair of the Department of Medicine, University of Pittsburgh School of Medicine and UPMC.