Optimizing the implementation of a participant-collected, mail-based SARS-CoV-2 serological survey in university-affiliated populations: lessons learned and practical guidance

Abstract

The rapid spread of SARS-CoV-2 is largely driven by pre-symptomatic or mildly symptomatic individuals transmitting the virus. Serological tests to identify antibodies against SARS-CoV-2 are important tools to characterize subclinical infection exposure.During the summer of 2020, a mail-based serological survey with self-collected dried blood spot (DBS) samples was implemented among university affiliates and their household members in Massachusetts, USA. Described are challenges faced and novel procedures used during the implementation of this study to assess the prevalence of SARS-CoV-2 antibodies amid the pandemic.Important challenges included user-friendly remote and contact-minimized participant recruitment, limited availability of some commodities and laboratory capacity, a potentially biased sample population, and policy changes impacting the distribution of clinical results to study participants. Methods and lessons learned to surmount these challenges are presented to inform design and implementation of similar sero-studies.This study design highlights the feasibility and acceptability of self-collected bio-samples and has broad applicability for other serological surveys for a range of pathogens. Key lessons relate to DBS sampling, supply requirements, the logistics of packing and shipping packages, data linkages to enrolled household members, and the utility of having an on-call nurse available for participant concerns during sample collection. Future research might consider additional recruitment techniques such as conducting studies during academic semesters when recruiting in a university setting, partnerships with supply and shipping specialists, and using a stratified sampling approach to minimize potential biases in recruitment.

Keywords: Epidemiologic methods; field epidemiology; SARS-CoV-2; Serology; Serosurveys.

Fig. 1

Contents of shipped bio-boxes. Example of box mailed to study households, which contained: dried blood spot collection cards with barcodes, two silica packets per DBS card, collection supplies (gloves, lancets, gauze, alcohol pads, and adhesive bandages), biospecimen bags, return labels, tape to seal the box for return, and instruction sheets for how to collect the sample and how to close the biospecimen bag. Image was captured by the authors of this paper and all company logos have been hidden for copyright purposes

Fig. 2

Unanticipated logistics issues with packing, boxes, and bloodspots. A 1000 boxes set up for packing and shipping. B At-home test kit returned after experiencing water damage. C Bloodspot cards returned with some spots too small to use for analysis. All images were captured by the authors of this paper and all company logos have been hidden for copyright purposes

Fig. 3

Participant enrollment diagram, SARS-CoV-2 serosurvey, Massachusetts, USA, Jul-Aug 2020