With the current COVID-19 pandemic, healthcare professionals face higher infection risk arising from both community exposure and occupational hazards. As noted in a new study by Harvard and Massachusetts General Brigham researchers (Shenoy et al. 2020), COVID-19 polymerase chain reaction (PCR) tests show persistently positive results among healthcare workers.
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These positive PCRs pose a "formidable challenge" to health systems and hospitals, according to the researchers who highlight the importance of establishing sensible return to work (RTW) criteria for medical workers that got infected with the coronavirus. Appropriate RTW criteria can promote workforce preservation, the researchers say, aside from ensuring safety of both patients and healthcare staff.
In this study, Erica S. Shenoy MD, PhD, affiliated with Harvard Medical School and Massachusetts General Hospital, and colleagues assessed the test-based RTW criteria established by Massachusetts General Brigham (MGB) in response to COVID-19 pandemic. Average intervals until test-based clearance and the number of excess lost work days using test-based clearance were recorded.
The MGB system has a total of 78,000 personnel spread across two academic health centres, six community hospitals, two speciality hospitals, a rehabilitation network, as well as urgent care/community health centres, and home-based care programmes. Initially, employees were tested based upon symptom onset with respect to clinical duties. As MGB's testing capacity expanded, all employees with any symptoms consistent with COVID-19 were referred for testing.
Of 8,930 employees tested between 7 March and 22 April 2020, 1,049 (11.7%) were positive for SARS-CoV-2. Of those, 37 (3.5%) were hospitalised at an MGB institution within seven days of their positive test. Other study findings include:
- Among 590 employees with subsequent testing, 425 (72%) had at least one negative nasopharyngeal (NP) swab. The mean and median number of days from first positive to first negative were 17.1 (SD, 6.7) and 17 (IQR, 9), with a minimum of two days and a maximum observed of 38 days.
- Of the 425 workers with positive PCR test results, 263 (61.9%) had a sequential second negative NP. The mean and median number of days from first positive to second negative were 19.5 (SD, 6.1) and 19 (IQR, 8), with a minimum observed of six days, 25th percentile at 15 days, and a maximum observed at 37 days.
MGB implemented the following RTW criteria: resolution of fever without fever-reducing medications, improvement in respiratory symptoms, and at least two consecutive negative NP swabs collected ≥24 hours apart. A minimum interval of time from resolution of symptoms to first test of clearance was not specified.
The authors observed that MGB personnel diagnosed and treated for COVID-19 had prolonged recovery of viral RNA. This finding – long duration of PCR positivity – is consistent with previous studies. MGB's test-based clearance, the researchers point out, accounted for an additional 4,097 days of cumulative lost work time, corresponding to a mean of 7.2 additional days of work lost per employee than would have been accrued using the time plus symptom-based clearance method.
Notably, during the study period, additional evidence emerged regarding lack of transmission after recovery from symptoms, including viral load being shown to be highest at the time of symptom onset and then to decline within a week thereafter. This prompted a move away from a test-based strategy to a time plus symptom-based strategy for ending isolation and permitting RTW in healthcare settings.
On 3 May 2020, the Centers for Disease Control and Prevention (CDC) issued a memo supporting time plus symptom-based RTW criteria. In less than three weeks, MGB followed CDC's lead and discarded its test-based clearance in favour of the time plus symptom-based RTW criteria.
The researchers conclude: "If test-based criteria are used for RTW, we recommend establishing a minimum duration of days prior to test of clearance. Switching to time plus symptom-based clearance criteria will allow an earlier RTW for most workers and can aid in workforce preservation."