Antibody Duration After Infection From SARS-CoV-2 in the Texas Coronavirus Antibody Response Survey

Abstract

Understanding the duration of antibodies to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus that causes COVID-19 is important to controlling the current pandemic. Participants from the Texas Coronavirus Antibody Response Survey (Texas CARES) with at least 1 nucleocapsid protein antibody test were selected for a longitudinal analysis of antibody duration. A linear mixed model was fit to data from participants (n = 4553) with 1 to 3 antibody tests over 11 months (1 October 2020 to 16 September 2021), and models fit showed that expected antibody response after COVID-19 infection robustly increases for 100 days postinfection, and predicts individuals may remain antibody positive from natural infection beyond 500 days depending on age, body mass index, smoking or vaping use, and disease severity (hospitalized or not; symptomatic or not).

Keywords: COVID-19; SARS-CoV-2; antibodies; antibody duration.

Figure 1.

Plot of nucleocapsid antibody levels (N-test values) over time (unadjusted) with individual spaghetti plots. Time is measured in days since the self-reported coronavirus disease 2019 (COVID-19) infection. For each individual depicted, their infection date is day 0, and the date of their first and subsequent tests are chronologically arranged on the plot; later tests have longer days since infection.

Figure 2.

Predicting nucleocapsid antibody status varying demographics in the reference model. The dashed line at 1 represents when the N-test reports a positive antibody response. N-test value ≥ 1 is a positive antibody response. The solid black line represents the reference prediction curve, that is for a 50 to 64-year-old non-Hispanic white woman without chronic conditions, with healthy BMI, who has insurance coverage, was asymptomatic in their infection, was not hospitalized, and did not use tobacco or vaping. The effect of varying a covariate across its domain is shown: (A) varying age, (B) varying race\ethnicity, and (C) category of BMI status. Abbreviations: BMI, body mass index; COVID-19, coronavirus disease 2019; N-test, nucleocapsid antibody test.

Figure 3.

Predicting nucleocapsid antibody status by hospitalization and symptomatic status. The dashed line at 1 represents when the N-test reports a positive antibody response. N-test value ≥ 1 is a positive antibody response. The solid black line represents the reference prediction curve, that is for a 50 to 64-year-old non-Hispanic white woman without chronic conditions, with healthy BMI, who has insurance coverage, was asymptomatic in their infection, was not hospitalized, and did not use tobacco or vaping. The effect of varying a covariate across its domain is shown: (A) hospitalization status and (B) symptomatic/asymptomatic status. Abbreviations: BMI, body mass index; COVID-19, coronavirus disease 2019; N-test, nucleocapsid antibody test.