Incorporating medical students into an interdisciplinary, population-based study of SARS-CoV-2 infection in asymptomatic individuals in South Texas.

Background: Asymptomatic and pre-symptomatic infections may play a significant role in the spread of COVID-19 but determining prevalence of these infections in the general population is labor intensive.

Purpose: This approach describes an innovative surveillance strategy using teams of medical students and emergency medical technicians (EMTs). Medical students represent a highly trained but underutilized workforce in the pandemic response.

Methods: A household-level sampling frame generated a population-weighted representative sample of households in San Antonio, Texas. Households were included if an English or Spanish-speaking adult (≥18yo) answered the door and was willing to participate; excluded if household members had past or present COVID-19 symptoms or close contact with confirmed COVID-19 infection. Interdisciplinary teams of medical or medical/public health dual degree students paired with EMTs conducted a survey and instructed participants on how to self-administer nasal swabs among 502 community members without symptoms of COVID-19 from June 1-6, 2020, weeks prior to a community case surge.

Results: Of 502 participants, median age was 52 years and average household size was 3.1. Only 40% reported no medical risk factors for COVID-19 complications. Hypertension (23.6%) and diabetes (13.4%) were the most common pre-existing medical conditions; 29% of respondents reporting feeling at risk for SARS-CoV-2 during daily outside-of-the-home activities. All 502 SARS-CoV-2 PCR tests were negative, suggesting a prevalence range of 0%-1.2%.

Public health significance: It is unlikely that pre-symptomatic and asymptomatic COVID-19 infections in households without existing COVID-19 infections played a major role in the propagation of the epidemic at this point in time. While community-wide testing of individuals without symptoms of COVID-19 may be low yield in the context of low prevalence of symptomatic cases of COVID-19, medical students provided valuable support for community-based surveillance at a time when public health infrastructure was severely taxed.