Sequential serological surveys in the early stages of the coronavirus disease epidemic: limitations and perspectives

Abstract

Introduction: Estimates of the number of individuals infected by severe acute respiratory syndrome coronavirus 2 are important for health planning and establishment of expectations regarding herd immunity. Methods: Seven testing rounds of a serological survey were conducted at 1-week intervals between April 19 and May 31, 2020 in Teresina municipality. Results: Over the 7 weeks, serological positivity increased from 0.56% (95% confidence interval [CI]: 0.18%-1.30%) to 8.33% (95% CI: 6.61%-10.33%), representing 33-53 persons infected for each reported case. Conclusions: Serological screening may be an important tool for understanding the immunity of a population and planning community interventions.

Population-based prevalence surveys during the COVID-19 pandemic: a systematic review

“…The vast majority of studies (n=25; 67.6%) reported only antibody testing, while the exclusive use of RT-PCR were presented in 5 (13.5%), and both tests were conducted in 7 (32). Two studies showed overall unclear risk of bias (34,49).…”

“…Some authors seem to have not been concerned with managing this issue because even though the response rate was low, there was still an adequate sample (23,35,36,40,42). Repeated crosssectional studies featured a widely distinct prevalence estimate on each round (29,36,49,50). This trend might be caused by the ascending curve of infected people, following the epidemic's natural course.…”

“…The same proportion of studies validated their methods internally to report accuracy (16,21,23,24,30,32,(34)(35)(36)(37)(38)(39)45,50,52) or used sensitivity and specificity given by manufacturers or other external studies (18)(19)(20)22,36,(40)(41)(42)(44)(45)(46)(47)(48)(49)(50)(51). We also noticed that it is quite unclear if the field teams followed standardized protocols for the data collection and testing.…”

“…A strong trend was observed in relation to the sampling procedures used in Brazil. All studies used a standardized household sampling method based on census tracts (46)(47)(48)(50)(51)(52) or healthcare units (49). is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint…”

Confronting the threat of SARS‑CoV‑2: Realities, challenges and therapeutic strategies (Review)

“…IgM testing has been designed and validated, but currently limited information is available about the performance of these tests (48). Some tests may produce inaccurate results (49), suggesting gold immunochromatography assay and ELISA methods should be used to eliminate or reduce the impact of cross-reaction. Serological testing is helpful for preliminary screening of suspected and high-risk groups (50).…”