Fewer than 10% of adults developed antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) during the first wave of coronavirus disease 2019 (COVID-19) in the United States, and fewer than 10% of those with antibodies were diagnosed, according to data published in The Lancet.
Investigators employed a cross-sectional study where the remainder plasma from 28,503 randomly selected adult patients receiving dialysis in July was tested using Siemens Healthineers SARS-CoV-2 spike protein receptor binding domain total antibody chemiluminescence assay.
The sample population had similar age, sex, race, and ethnicity distribution compared to the US dialysis population, but higher proportion of older participants, men, and patients living in majority Black and Hispanic neighborhoods compared to the US adult population. The seroprevalence for SARS-CoV-2 was 8.0% (95% CI, 7.7-8.4), which rose to 8.3% (95% CI 8.0-8.6) when standardized to the US dialysis population and to 9.3% (95% CI 8.8-9.9) when standardized to the US adult population.
When looking at seroprevalence standardized to the US dialysis population, seroprevalence ranged from 3.5% (95% CI, 3.1–3.9) in the west to 27.2% (95% CI, 25.9–28.5) in the northeast. Only 9.2% of seropositive patients were diagnosed (95% CI, 8.7-9.8%), according to data when comparing seroprevalence and case counts per 100,000 population. Study authors also reported that compared with other measures of SARS-CoV-2 spread, death per 100,000 population was the best correlation with seroprevalence (Spearman’s P =.77).
Patients that saw increased odds of seropositivity include those who live in predominantly Black (odds ratio [OR], 3.9; 95% CI, 3.4-4.6) and Hispanic (OR, 2.3; 95% CI, 1.9-2.6) neighborhoods compared to White neighborhoods, and those who live in the highest population density quintile compared to those who live in the lowest density quintile (OR, 10.3; 95% CI, 8.7-12.2). Participants who had workplace visits reduced by at least 5% due to county mobility restrictions saw lower odds of seropositivity compared to participants who reduced workplace visits by less than 5% (OR, 0.4; 95% CI, 0.3-0.5).
The study had several limitations including overestimated seroprevalence in the US population, lack of data on patient socioeconomic factors, and underrepresentation of rural areas. While the study was large, authors note that the study was not designed for state-level or county-level estimates, rather precise regional ones.
In this “broadly representative sample of US dialysis patients,” data shows “striking differences in seroprevalence by several patient characteristics, with higher seroprevalence in younger patients, Black and Hispanic patients, and patients living in poorer and majority-minority neighborhoods.” This data can assist in building “management strategies during the next phase of the pandemic,” the study authors concluded.
Anand S, Montez-Rath M, Han J, et al. Prevalence of SARS-CoV-2 antibodies in a large nationwide sample of patients on dialysis in the USA: a cross-sectional study. The Lancet. Published online September 25, 2020. doi: 10.1016/S0140-6736(20)32009-2