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Prevalence of SARS-Cov-2 Antibodies in Patients on Dialysis
TAKE-HOME MESSAGE
- In a random sampling of US patients receiving dialysis, researchers found that 8% of patients were antibody-positive for SARS-CoV-2, which generalizes to 9.3% of the US adult population. The prevalence of antibody positivity varied regionally, with the highest rates seen in the Northeast (27.2%). It was estimated that only 1 in 10 patients who had SARS-CoV-2 antibodies had previously been diagnosed with COVID-19.
- The data presented in this article match much of the data in the reports distributed by public health officials, showing that we are probably underestimating the true impact of COVID-19.
– Andrea Dotson, MD, MSPH
abstract
This abstract is available on the publisher's site.
Access this abstract now Full Text Available for ClinicalKey SubscribersBACKGROUND
Many patients receiving dialysis in the USA share the socioeconomic characteristics of underserved communities, and undergo routine monthly laboratory testing, facilitating a practical, unbiased, and repeatable assessment of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) seroprevalence.
METHODS
For this cross-sectional study, in partnership with a central laboratory that receives samples from approximately 1300 dialysis facilities across the USA, we tested the remainder plasma of 28 503 randomly selected adult patients receiving dialysis in July, 2020, using a spike protein receptor binding domain total antibody chemiluminescence assay (100% sensitivity, 99·8% specificity). We extracted data on age, sex, race and ethnicity, and residence and facility ZIP codes from the anonymised electronic health records, linking patient-level residence data with cumulative and daily cases and deaths per 100 000 population and with nasal swab test positivity rates. We standardised prevalence estimates according to the overall US dialysis and adult population, and present estimates for four prespecified strata (age, sex, region, and race and ethnicity).
FINDINGS
The sampled population had similar age, sex, and race and ethnicity distribution to the US dialysis population, with a higher proportion of older people, men, and people living in majority Black and Hispanic neighbourhoods than in the US adult population. Seroprevalence of SARS-CoV-2 was 8·0% (95% CI 7·7-8·4) in the sample, 8·3% (8·0-8·6) when standardised to the US dialysis population, and 9·3% (8·8-9·9) when standardised to the US adult population. When standardised to the US dialysis population, seroprevalence ranged from 3·5% (3·1-3·9) in the west to 27·2% (25·9-28·5) in the northeast. Comparing seroprevalent and case counts per 100 000 population, we found that 9·2% (8·7-9·8) of seropositive patients were diagnosed. When compared with other measures of SARS-CoV-2 spread, seroprevalence correlated best with deaths per 100 000 population (Spearman's ρ=0·77). Residents of non-Hispanic Black and Hispanic neighbourhoods experienced higher odds of seropositivity (odds ratio 3·9 [95% CI 3·4-4·6] and 2·3 [1·9-2·6], respectively) compared with residents of predominantly non-Hispanic white neighbourhoods. Residents of neighbourhoods in the highest population density quintile experienced increased odds of seropositivity (10·3 [8·7-12·2]) compared with residents of the lowest density quintile. County mobility restrictions that reduced workplace visits by at least 5% in early March, 2020, were associated with lower odds of seropositivity in July, 2020 (0·4 [0·3-0·5]) when compared with a reduction of less than 5%.
INTERPRETATION
During the first wave of the COVID-19 pandemic, fewer than 10% of the US adult population formed antibodies against SARS-CoV-2, and fewer than 10% of those with antibodies were diagnosed. Public health efforts to limit SARS-CoV-2 spread need to especially target racial and ethnic minority and densely populated communities.
Additional Info
Disclosure statements are available on the authors' profiles:
Prevalence of SARS-Cov-2 Antibodies in a Large Nationwide Sample of Patients on Dialysis in the USA: A Cross-Sectional Study
Lancet 2020 Sep 25;[EPub Ahead of Print], S Anand, M Montez-Rath, J Han, J Bozeman, R Kerschmann, P Beyer, J Parsonnet, GM ChertowFrom MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
Nationwide Seroprevalence of SARS-CoV-2
When faced with a virus that does not always cause recognizable symptoms and one for which testing is not always available due to time, location and health equity issues, a recurring question is: “How widespread is SARS-CoV-2?” As of mid-October, 2020, the United States has recorded nearly 8 million laboratory confirmed cases. A simple calculation would suggest a nationwide prevalence of about 2.4%, but that misses all of those mild or otherwise undetected cases. This gets back to the problem with denominators that I discussed earlier in a commentary.[1] A possible solution comes in the form of assessing seroprevalence, the presence of SARS-CoV-2-specific antibody, which can be a more enduring marker of infection.
Developing a nationwide sampling frame, recruiting participants, collecting specimens, and completing testing is a daunting and expensive endeavor. An innovative approach to this problem involved the use of remainder plasma available at a central testing laboratory. This laboratory received specimens from dialysis patients from 1300 dialysis centers across the country.[2] Plasma samples, collected in July, and randomly selected from 28,503 individuals were evaluated for antibody to the spike protein receptor binding domain of SARS-CoV-2. Patient level data were available on age, sex, race and ethnicity, along with residence location. The sample population was older, more male, and with higher representation of Black and Hispanic individuals than U.S. adult population.
Some interesting trends emerged from the analyses. Overall, 8.0% of the specimens were antibody positive; rising to 9.3% when adjusted to the composition of the U.S. adult population. Significant seropositivity rate differences emerged across many patient characteristics:
The estimated seroprevalence rates were significantly correlated with COVID-19 death rates across geographical areas. In addition, based on external estimates of cases diagnosed through nasal swab testing, the seroprevalence rates were almost 11 times greater, implying that most cases are not ascertained through our testing programs.
This sampling frame is far from perfect, as dialysis patients are not representative of the general population. Nevertheless, this nationwide seroprevalence study implies that SARS-CoV-2 is more widespread than the reported cases suggest. More importantly, the highly significant national toll of morbidity, hospitalization, and mortality is based on a relative small proportion of individuals contracting SARS-CoV-2. Furthermore, this study helps to illuminate the health disparities based on race, ethnicity and income that amplify the effects of COVID-19 in our communities.
References