Having “close contact” with COVID-19 is normally outlined as being close to an contaminated individual for no less than 15 consecutive minutes. However a brand new report means that even very transient exposures — a minute or much less — may unfold the illness, if these exposures occur often.
The report, from the Facilities for Illness Management and Prevention (CDC), describes a correctional officer in Vermont who caught COVID-19 after publicity to contaminated prisoners, despite the fact that he was by no means across the contaminated individuals for greater than a minute at a time.
The publicity doubtless occurred on July 28, when six inmates have been transferred to the Vermont jail from an out-of-state facility, based on the report, printed in the present day within the CDC journal Morbidity and Mortality Weekly Report. Not one of the inmates confirmed symptoms of COVID-19, however all of them underwent routine testing for COVID-19 upon arrival; and all six inmates obtained constructive outcomes the subsequent day.
After studying of the constructive outcomes, officers went again to see who had shut contact with the inmates the day earlier than. The crew reviewed video footage and located one correctional officer who did come inside 6 ft (1.8 meters) of the inmates, however was not thought of a detailed contact as a result of he was not across the contaminated individuals for 15 consecutive minutes.
The officer continued to work as standard, however on Aug. 4 (one week after the contaminated inmates arrived), he developed lack of odor and style, runny nostril, cough, shortness of breath, headache and different signs of COVID-19, the report mentioned. The subsequent day, the officer examined constructive for the illness.
Because of this constructive take a look at, officers as soon as once more reviewed the video surveillance footage from July 28. Although the correctional officer by no means spent quarter-hour straight near the contaminated inmates, he had a number of transient encounters with them. Particularly, throughout his 8-hour shift, the officer had 22 transient encounters (between 10 and 60 seconds every) with the inmates, totaling 17 minutes of cumulative publicity.
The correctional officer wore a cloth mask and goggles throughout his encounters, however the inmates weren’t at all times masked. The officer had no different identified contacts with COVID-19 and hadn’t traveled outdoors of Vermont within the 2 weeks earlier than his sickness. As well as, the speed of latest COVID-19 infections in Vermont was low on the time, that means the officer was unlikely to catch the illness via neighborhood unfold.
The findings recommend that “no less than one of many asymptomatic [inmates] transmitted SARS-CoV-2 [the virus that causes COVID-19] throughout these transient encounters,” the report authors mentioned.
The findings have implications for contact tracing, which normally defines “shut contact” with an individual contaminated with the novel coronavirus as being inside 6 ft for no less than quarter-hour. Extra elements may additionally be thought of, corresponding to how shut the people got here to one another, whether or not the contaminated individual was doing one thing like singing or exercising, which generates loads of respiratory aerosols and whether or not the atmosphere was crowded or adequately ventilated, the report mentioned.
Within the present case, “though the preliminary evaluation didn’t recommend that the officer had shut contact exposures, detailed evaluation of video footage recognized that the cumulative length of exposures exceeded quarter-hour,” the authors wrote. In correctional settings, frequent shut encounters between inmates and facility employees members are needed, the authors mentioned, and “public well being officers ought to take into account transmission-risk implications of cumulative publicity time inside such settings,” they concluded.
Initially printed on Dwell Science.