PROVIDENCE – A top Rhode Island infectious-disease specialist is urging “universal masking” until herd immunity from COVID-19 is achieved – and after that, in indoor environments, especially during winter, where social distancing is difficult or impossible and where air quality is deficient.
So asserts Dr. Leonard A. Mermel, medical director, epidemiology & infection control, Rhode Island Hospital, and a Brown University professor of medicine, in a recent letter to the scientific journal Infection Control & Hospital Epidemiology.
In his letter, Mermel noted that the Moderna and Pfizer vaccines now being administered in Rhode Island and the U.S. are highly effective – but he cautions that “how long the protection lasts beyond a few months is uncertain at the present time.”
He cited the case of an unnamed “otherwise healthy adult” who became re-infected six month after the initial bout with the disease “despite production of neutralizing antibodies after the first infection. This individual apparently spread COVID-19 while re-infected.”
With this in mind, Mermel wrote that once herd immunity is reached by means of vaccines and “natural disease,” universal masking should continue in congregate settings and other indoor settings where social distancing cannot be maintained and/or the introduction of fresh air introduced into the environment, or filtration of recirculated air, is suboptimal.”
Mermel said that “widespread vaccination will inevitably reduce the COVID-19 reproductive number, thereby changing the transmission dynamics in many parts of the world. However, infection among those unvaccinated and reinfection in unvaccinated and vaccinated individuals remains an ongoing concern.”
He added: “By reducing transmission of respiratory viruses, masking should reduce immune selection pressure in infected individuals, and lower the likelihood that severe acute respiratory coronavirus virus 2 (SARS-CoV-2) will become more transmissible in the future.
“There will be temptation to lower our guard and not follow advice about social distancing and masking after vaccination. However, we must learn from our experience over the past year. Failure to maintain more than a modicum of masking would reflect an inability to learn from the past to improve our lives in the future.”