CDC Updates Social Distancing Guidelines

An updated version of just what constitutes close contact with a person with coronavirus disease 2019 (COVID-19) will greatly increase the number of people who could consider themselves at risk for contracting COVID-19. The guidelines that the US Centers for Disease Control and Prevention had been working under said that close contact more or less means being 6 feet or less from an infected person for 15 minutes or more. The updated guidelines, partly precipitated by a new study in the CDC’s Morbidity and Mortality Weekly Report (MMWR), says that the contact doesn’t need to be for 15 or more consecutive minutes. The contact could constitute multiple encounters with an infected person of 6 feet or less that adds up to 15 or more minutes.

Investigators say that a corrections officer in a Vermont prison had had “multiple brief encounters” with whom the study defines as 6 incarcerated or detained persons (IDPs) who had COVID-19 but did not know it yet. The 6 people had been tested for COVID-19 but had not yet gotten their results back.

“During his 8-hour shift on July 28, the correctional officer was within 6 feet of an infectious IDP an estimated 22 times while the cell door was open, for an estimated 17 total minutes of cumulative exposure,” the study states. “IDPs wore microfiber cloth masks during most interactions with the correctional officer that occurred outside a cell; however, during several encounters in a cell doorway or in the recreation room, IDPs did not wear masks.”

The corrections office did wear a microfiber cloth mask, gown, and goggles during all the interactions, and he wore gloves most of the time. “The correctional officer’s cumulative exposure time is an informed estimate; additional interactions might have occurred that were missed during this investigation,” the study states.

CDC investigators say that there is no precise definition of what close contact means, but it’s generally agreed among healthcare providers that it’s about 15 minutes of contact with an infected person who is 6 feet or less away.

“Additional factors to consider when defining close contact include proximity, the duration of exposure, whether the infected person has symptoms, whether the infected person was likely to generate respiratory aerosols, and environmental factors such as adequacy of ventilation and crowding,” the study states. “A primary purpose of contact tracing is to identify persons with higher risk exposures and therefore higher probabilities of developing infection, which can guide decisions on quarantining and work restrictions. Although the initial assessment did not suggest that the officer had close contact exposures, detailed review of video footage identified that the cumulative duration of exposures exceeded 15 minutes. In correctional settings, frequent encounters of ≤6 feet between IDPs and facility staff members are necessary; public health officials should consider transmission-risk implications of cumulative exposure time within such settings.”

An unidentified source within the CDC told the Washington Post that scientists at the agency had been discussing updating the social distancing for weeks, and the MMWR study seems to have pushed them into making that decision.

As the Washington Post indicates, the new guidelines are likely to be most felt in workplaces, schools and group settings where people are more likely to have the disjointed encounters with those infected by SARS-CoV-2. Infection preventionists and other healthcare professionals use the guidelines to, among other things, determine who should be the subject of contact tracing.

The changed guidance comes as many states deal with an uptick in COVID-19 cases, hospitalizations, and morality rates.

In the United States, there have been about 8.3 million confirmed cases of COVID-19, and about 222,000 people have died from COVID-19, according to Johns Hopkins University. In the world, there have been about 41.3 million confirmed cases of COVID-19 and about 1.13 million people have died from COVID-19.