key: cord-0866340-ij79jki6
authors: Althoff, Ashley; Papasavas, Pavlos; Olugbile, Sope; Wu, Ulysses; Roberts, Amity L.; O'Sullivan, David M.; McLaughlin, Tara; Mather, Jeff F.; Steinberg, Adam C.; Orlando, Rocco; Kumar, Ajay
title: Factors Affecting Seroreversion by 6 months among Healthcare Workers in Connecticut
date: 2021-12-09
journal: J Hosp Infect
DOI: 10.1016/j.jhin.2021.12.001
sha: e55cad20512c367912cffa857fc00f508c29bed7
doc_id: 866340
cord_uid: ij79jki6

nan

Healthcare workers (HCW) are at a high risk of coronavirus 2019 (COVID-19) infection and exposure [1, 2] . COVID-19 infection results in production of neutralizing antibodies [3] . These antibodies can be detected from 10 days up to 10 months after onset of symptoms [4] . Antibodies provide protective immunity against re-infection [5] ; therefore, understanding factors that predict the kinetics of antibody decay (seroreversion) [6] after COVID-19 infection is important to better understanding those at risk for repeat infection. As a follow-up to a study conducted with HCWs at the largest healthcare system in Connecticut [2] , we sought to evaluate factors associated with seroreversion after baseline positive severe acute respiratory syndrome coronavirus (SARS-CoV-2) immunoglobin G (IgG) antibody.

30,000 HCW and medical staff were invited to participate via electronic communication. Inclusion criteria were: current employment or affiliated medical staff at least 18 years old without symptoms of COVID-19 at time of testing. Testing occurred from May 11 to August 22, 2020. Participants provided electronic consent and completed a questionnaire in REDCap (Research Electronic Data Capture; Vanderbilt University, Nashville, TN). Patient demographics, strength of first positive antibody signal, comorbidities (obesity, cancer, diabetes, pregnancy, immunodeficiency, heart disease, chronic lung disease, liver disease, hematologic disorder, chronic kidney disease, neurologic disorder, organ/bone marrow recipient), frequency of contact with COVID-19 patients (none, occasional, daily), time between blood draws, symptoms of COVID-19, high-risk exposure at work, exposure outside work, and need for home quarantine were reported. Participants were invited to undergo blood draws at initial visit, 2-4 weeks and 3-6 months after initial visit. Semi-quantitative IgG immunoreactivity to SARS-CoV-2 was performed using the Architect SARS-CoV-2 IgG assay. Patients with a positive IgG at either the first or second blood draw who also underwent a third blood draw were included in this analysis. Patients were analyzed for the presence or IgG antibodies at the third blood draw. The main outcomes were factors associated with seroreversion by 6 months. Association between these variables and seroreversion was evaluated using a logistic regression analysis, reported with odds ratio (OR) and 95% confidence interval (CI). SPSS v. 26 (IBM; 2019) was used for analyses, with p<0.05 deemed statistically significant.

Of the 6,863 participants tested, 433 were seropositive (i.e., IgG index ≥1.4U) at either the initial or second draw; 278 went on to have a third draw. Of these, 171 (61.5%) were seropositive and 107 (38.5%) were seronegative. (Table 1) .

Following COVID-19 infection, the majority of patient develop viral spike receptor-binding antibodies [7] . Development of neutralizing antibodies are effective in preventing re-infection and may have neutralizing activity for up to a year as well as possible long-term memory humoral response; however, these decrease over time [3, 8] . Weak evidence has demonstrated sustained positivity rate of antibodies to be dependent on older age, male sex, viral protein type (spike or nucleocapsid), and severity of symptoms [4, 5] . In this study, seroreversion by 6 months was associated with lower initial antibody assay signal, daily exposure to COVID-19, and home quarantine. This suggests that decreased durability of immune response over time may be associated with less initial immunologic response, and low-dose exposures may induce a less robust and durable immune response.

Study limitations include voluntary testing limited to employees with access to communication via electronic devices, sample size, lack of randomization, lack of continued follow-up and questionable representation of the larger HCW population. Strength of signal only included semi-quantitative data and may be enhanced through quantitative data in the future.

Determining factors associated with seroreversion in HCW following COVID-19 infection is important to predict those at risk for decreased immunity. Low antibody titer, home quarantine, and repetitive daily COVID-19 exposures may be associated with less durable immune response following COVID-19 infection.

This work was funded internally by the authors' hospital. 

Epidemiology of and Risk Factors for Coronavirus Infection in Health Care Workers: A Living Rapid Review

Seroprevalence of SARS-CoV-2 antibodies, associated epidemiological factors and antibody kinetics among healthcare workers in Connecticut

Naturally enhanced neutralizing breadth against SARS-CoV-2 one year after infection

A population-based analysis of the longevity of SARS-CoV-2 antibody seropositivity in the United States

Antibody Response After SARS-CoV-2 Infection and Implications for Immunity : A Rapid Living Review

Antibody Dynamics, Seroreversion, and Persistence After SARS-CoV-2: Another Answer

Virological assessment of hospitalized patients with COVID-2019

Evolution of antibody immunity to SARS-CoV-2