In a large nursing home study, asymptomatic and symptomatic residents were found to carry similar viral loads.
With high transmission and mortality rates, nursing homes and assisted living facilities have been one of the hardest hit places during the COVID-19 pandemic.
In a large study completed in Massachusetts, nursing home residents and staff who were tested for COVID-19 were found to have similar viral loads whether they were asymptomatic or symptomatic.
“In a large cohort of individuals screened for SARS-CoV-2 by RT-qPCR, we found strikingly similar viral load distributions in patients with or without symptoms at the time of testing,” the investigators reported.
The testing carried out from April 9 to June 9, consisted of 3480 nursing home and assisted living residents and staff. The residents consisted of 16966, were 65% female, and had a mean age 82. In looking at the staff cohort, there were 15514, with 76% being female and the mean age was 45.
Overall, 2654 residents (15.5%) and 624 staff (4.1%) tested positive for SARS-CoV-2. Within this, 12.7% of residents and 3.7% of staff without symptoms, compared to 53.1% of residents and 18.2% of staff with symptoms.
“The Ct distributions for viral probes were very similar between populations with and without symptoms,” the investigators reported. “With a statistically but not meaningfully different mean (ΔCt 0.71 cycles, p = 0.006) and a similar range (12-38 cycles). This similarity persisted across all sub-categories examined (age, race, ethnicity, sex, resident/staff).”
“The size of the study population, including both staff and residents spanning a wide range of ages, provides a comprehensive cross-sectional point prevalence measurement of viral burden,” the investigators wrote. “Because the distributions of viral loads are very similar regardless of symptoms, existing testing modalities validated for detection of SARS-CoV-2 RNA in symptomatic patients should perform similarly well in individuals without symptoms at the time of testing.”
This study, Comparison of Viral Loads in Individuals With or Without Symptoms At Time of COVID-19 Testing Among 32,480 Residents and Staff of Nursing Homes and Assisted Living Facilities in Massachusetts, was presented as a late breaking abstract at IDWeek 2020.