key: cord-0739672-buzoqggj
authors: Stout, R.; Rigatti, S.
title: The Change in Seroprevalence in the US plus Puerto Rico between May and September of SARS-CoV-2 Antibody in the Asymptomatic Population
date: 2020-11-13
journal: nan
DOI: 10.1101/2020.11.10.20215145
sha: 0bd3ea93e0bf778e315a7fae8cee5eaa0784d189
doc_id: 739672
cord_uid: buzoqggj

Objective: Determine the seroprevalence and 3 month temporal change of SARS-COV-2 in the US and Puerto Rico in an asymptomatic well population. Results: The prevalence of SARS-CoV-2 in the asymptomatic population has doubled during the May to September time period, going from 3.0% to 6.6%. Positive serology to SARS-COV-2 was similar in males and females but varies by age. The greatest increase was in the youngest population. Based on the September prevalence it is estimated that there are 11.1 million (bootstrap 95% CI: 10.8 - 11.5 million) asymptomatic SARS-CoV-2 infections in the US, which is 1.95 times the cumulative number of cases in the US reported to the CDC as of September 1, 2020. . Conclusions: The number of new SARS-COV-2 cases more than doubled in this 3 months period. The seroprevalence by age group is high in the youngest (<20, 7.8%) and low in the oldest (> 70, 2.0%). Over the three month study period the rate of increase in prevalence for SARS-COV-2 serology varies by state with a range from 0.84 (State of New York) to more than 12 (Tennessee). This study identifies states were public health mitigation has blunted the spread and also areas where additional levels of intensified public education, surveillance and targeted intervention may be warranted.

The Change in Seroprevalence in the US plus 8 Puerto Rico between May and September of 9 SARS-CoV-2 Antibody in the Asymptomatic In early 2020 a novel coronavirus emerged in Hubei Province, China 1 . The 7 0 causative agent was a betacoronavirus most closely related genetically to zoonotic 7 1 viruses found in bats, and clinically similar to recent emergent epidemic 7 2 coronaviruses which caused Severe Acute Respiratory Syndrome (SARS) and 7 3

Middle Eastern Respiratory Syndrome (MERS) 2 . Since then, the virus has 7 4 become a worldwide pandemic, infecting over 37 million persons and causing more Prevention has recommended that all states report laboratory-confirmed cases 5 .

Case counts have been closely tracked by the CDC, the press, and academic 7 9

institutions. However, because the illness caused by SARS-CoV-2 may be Because SARS-CoV-2 is novel, the presence of antibodies in the blood likely 8 7

indicates a history of infection since the pandemic began, and serologic testing can 8 8 be used to estimate the overall rate of infection, even in those who had minimal 8 9

symptoms or who were never tested despite symptoms. In this study, a convenience sample of blood specimens submitted to a commercial 9 2 laboratory was used to conduct a survey of seroprevalence over a three month 9 3 study period. The goal was to estimate the seroprevalence and overall rate of 9 4

increase or decrease in positivity nationally and state by state.

. CC-BY-NC 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) preprint

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Method: In the United States, the process of purchasing life insurance often 9 6 involves a brief physical examination by paramedical professionals, the collection of 9 7 height, weight and blood pressure measurements, and the testing of blood and 9 8 urine specimens for common laboratory test related to overall health. Such tests are 9 9 seldom, if ever, performed on individuals below age 16 years or above 85 years. The differences in continuous variables between the antibody-positive and negative 1 1 0 groups were tested for significance with the Mann-Whitney U test, while differences 1 1 1 in categorical variables were tested using the chi-square test. All statistical 1 1 2 analyses were performed using R (version 3.6.1) 9 and R-studio (version1.2.1335) 10 . The overall sample included 113,369 individuals with a median age of 42 years 1 2 5 (IQR: 33-54), 55.5% of whom were male. Geographical distribution deviated 1 2 6 . CC-BY-NC 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) preprint

The copyright holder for this this version posted November 13, 2020. ; https://doi.org/10.1101/2020.11.10.20215145 doi: medRxiv preprint somewhat from the overall population distribution of the US, with some under- population are displayed in Table 1 . The antibody positive group tended to be 1 3 0 slightly younger (median age 41) vs. the antibody negative group (median age 42).

The distribution by decade of age is displayed in Table 2 . This study estimated the 2020. The rate of positivity ranged from 0% to 14.7% by state and from 2-7.8% infections occurred than were reported. This is likely due to asymptomatic or 1 4 0 minimally symptomatic infections for which care was not sought or symptomatic 1 4 1 infection for which testing was not available or obtained. differed by region and was earlier than the current study. The authors 1 5 0 estimated that the seroprevalence implied that between 6 and 24 times the number 1 5 1 of infections had occurred in the studied regions than had been reported. City between late February and mid-April 2020 12 . Over this period of time . CC-BY-NC 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) preprint

The copyright holder for this this version posted November 13, 2020. ; https://doi.org/10. 1101 /2020 The collection period was from April 19 to 28, 2020, and the estimate was 22.7%.

The higher estimate than the current study, despite being performed in an earlier 1 5 9 time period, is likely due to a geographical distribution that is more localized to the 1 6 0 highest prevalence metro region, rather than the entire state of New York. We report that, around the time of study, the number of infections in the US was 1 6 2 nearly 2 times higher than cases of infection reported suggesting a much more states, as well as the lack of samples from those under age 16 or over age 80. The age distribution is also more heavily weighted to the young adult years, which is not seroprevalence. Finally, the life insurance-buying population tends to be both 1 7 0 healthier and mid-income or wealthier than average, and this could also bias the presented in this report should provide the "facts to support" these changes. CC-BY-NC 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) preprint

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Both authors contributed equally to the development of this data, the statistical Figure 1 . CC-BY-NC 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) preprint

The copyright holder for this this version posted November 13, 2020. ; https://doi.org/10.1101/2020.11.10.20215145 doi: medRxiv preprint T a b l e s 1 -3 

3%) 1155 (6.7%)