An Epidemiologic Study of COVID-19 Patients in a State Psychiatric Hospital: High Penetrance With Early CDC Guidelines

This study was reviewed by the Tulane University institutional review board and determined to be exempt. Existing, deidentified data analyzed in this study included 160 COVID-19 tests collected from patients in an inpatient psychiatric hospital between March 14 and April 8, 2020. Sixty-eight tests of symptomatic patients were collected using state labs. The Tulane University School of Medicine lab provided an additional 92 tests for a sample of asymptomatic patients by using a CDC 2019 novel coronavirus (2019-nCoV) real-time reverse transcription–polymerase chain reaction (RT-PCR) diagnostic panel (7). By the time the 92 additional patients were tested between April 2 and April 4, 2020, three had become symptomatic, 19 were mildly symptomatic, and 70 remained asymptomatic. Of the 92 additional tests, 41% (N=38) were performed on the remaining patients in building zero who had not yet been tested. The other 59% (N=54) were performed on a random sample of asymptomatic patients throughout three other buildings in the hospital where transmission had recently begun. Patients were randomly selected for testing, excluding those who had already been tested and ensuring that at least one patient was chosen from each unit of the buildings. Analyses were conducted using SPSS, version 24.

A majority of patients in this study were male (N=113, 71%), with a mean±SD age of 51.27±13.91 years (range 23.74–76.36). Two-thirds (N=106, 66%) identified as Black, 33% (N=53) as white, and 1% (N=1) as Hispanic. Results from all 160 tests are presented in Table 1. The positive-to-negative ratio (51:14) of building zero equates to the alarmingly high rate of 78% positive COVID-19 results among clients with valid test results. The positive-to-negative ratio (28:57) of the other buildings sampled showed a much lower rate of positive tests, at 33%. When we examined the 150 valid test results (excluding 10 pending), a chi-square test (with Yates’s continuity correction) indicated that those in building zero were significantly more likely to test positive than were those in other buildings (χ²= 28.82, df=1, p=<0.001, ϕ=0.45).

The subset of 67 tests of asymptomatic patients who had valid test results (excluding three pending) was further examined. A chi-square test (with Yates’s continuity correction and Fisher’s exact test) indicated that those in building zero were significantly more likely to test positive than were those in other buildings (χ²= 29.84, df=1, p<0.001, ϕ=0.71).

These are preliminary data from testing conducted on symptomatic and asymptomatic patients in a state psychiatric hospital where the COVID-19 virus has spread rapidly despite substantial preparation and use of up-to-date CDC guidelines. Results demonstrate that many asymptomatic or mildly symptomatic patients were positive for COVID-19. It appears that CDC guidelines were not sufficient for containing spread in these close-quarter settings.

Although physical distancing is recommended for limiting the spread of COVID-19, such distancing is not possible in close-quarter, confined settings. As such, some state prisons and county jails have decreased bail or released inmates early to decrease spread of the virus. However, given the nature of the offenses of patients in long-term psychiatric settings, combined with their high need for care, releasing patients is not a feasible option. Use of field tents may be a solution for decreasing crowding and increasing physical distance; however, this is not possible in all settings.

Given the difficulties with physical separation, additional measures, such as universal masking, must be taken. Because of the high number of asymptomatic and mildly symptomatic patients who tested positive in this study, waiting to implement masking until the first symptomatic patient tests positive is not recommended. Of course, the limited availability of PPE must be taken into consideration. Another possible preventative measure is to test all staff members who have contact with patients, whether or not they are showing common COVID-19 symptoms. It is possible that asymptomatic staff members may play a role in the introduction or spread of the virus. Unfortunately, with limited testing available, tests are typically reserved for symptomatic patients and staff.

Although the exact source of COVID-19 in the hospital in this study is unknown, hospital administrators suspect that either an asymptomatic staff member introduced the virus or that patient zero was exposed during an off-campus medical appointment that occurred 12 days before he or she became symptomatic and just 1 day before all off-campus appointments were cancelled.

The ability to test asymptomatic patients was a strength of this study and allowed for an estimate of asymptomatic transmission of COVID-19 in close-quarter settings. However, the results should be interpreted with the study’s limitations in mind. Because of limited available testing, not all patients in the hospital were able to be tested. Thus, the penetrance rates provided are estimates based on subsamples.

It is recommended that all close-quarter psychiatric facilities consider using universal masking prior to discovering the initial case of COVID-19. Waiting for positive test results may result in rapid infection by symptomatic and asymptomatic infected patients.

The authors appreciate the assistance of Robert Garry, Ph.D., professor of microbiology and immunology at Tulane University School of Medicine, and of Xiao-Ming Yin, M.D., Ph.D., professor and chair of pathology and laboratory medicine at Tulane University School of Medicine, who facilitated and coordinated testing.