SARS-CoV-2 IgG antibody responses in New York City

Abstract

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is a strain of coronavirus that causes coronavirus disease 2019 (Covid-19) and has been declared a global pandemic by the World Health Organization. Total cases of SARS-CoV-2 worldwide exceed 10.2 million, with over 503,000 deaths recorded. Little is known about the body's immune response to SARS-CoV-2 infection. In this paper, we describe SARS-CoV-2 IgG antibody responses in 28,523 patients from the New York City metropolitan area and report a SARS-CoV-2 IgG positivity rate of 44%, indicating the widespread nature of the pandemic in the city and state of New York. Additionally, for a subset of patients, we report on the correlation between SARS-CoV-2 patient symptom severity and level of SARS-CoV-2 IgG antibody found in the patient sample.

Fig. 1

Age versus Symptom Severity Index. (A) Patient age is plotted versus symptom severity index (SSI) for all 240 patients given an SSI. Blue line represents the regression line and gray shading represents the 95% confidence interval of the regression. The correlation between age and SSI is statistically significant at P < 0.01 (B) Patient age is plotted versus symptom severity index (SSI) for all 240 patients given an SSI and broken down by patient sex. The linear regression line for males (blue line) and females (red line) along with 95% confidence intervals of the regressions (gray shading) are shown. The correlation between age and SSI is statistically significant for both male and female patients at P < 0.01.

Fig. 2

SARS-CoV-2 IgG Index Level versus Symptom Severity Index. (A) SARS-CoV-2 IgG index level (AU/mL) is plotted versus symptom severity index (SSI) for all 240 patients given an SSI. Blue line represents the regression line and gray shading represents the 95% confidence interval of the regression. The correlation between SARS-CoV-2 IgG level and SSI is statistically significant at P < 0.01 (B) SARS-CoV-2 IgG index level (AU/mL) is plotted versus symptom severity index (SSI) for all 240 patients given an SSI and broken down by patient sex. The linear regression line for males (blue line) and females (red line) along with 95% confidence intervals of the regressions (gray shading) are shown. The correlation between SARS-CoV-2 IgG level and SSI is statistically significant for both male and female patients at P < 0.01.

Fig. 3

Patient SARS-CoV-2 IgG positivity rates. Histogram of SARS-CoV-2 IgG positivity rate by patient age for 28,523 patients from the New York City metropolitan area. Patients were binned into 5-year age groups and the positivity rate for each age group is plotted. SARS-CoV-2 IgG positivity rates ranged from 24.5% in patients aged 86–90 to 57.3% in patients aged 16–20 years. The blue dotted line represents a fitted regression line intended to show trends.

Fig. 4

SARS-CoV-2 IgG Index Values by Age. (A) The mean SARS-CoV-2 IgG index values (AU/mL) of the 12,424 SARS-CoV-2 IgG positive patients in this study for each age are plotted versus patient age. The mean values for males (orange line), females (gray line), and both sexes (blue line) are plotted. The mean index value for all positive patients was 108.4 AU/mL (black dashed line). (B) The mean SARS-CoV-2 IgG index values (AU/mL) of the 12,424 SARS-CoV-2 IgG positive patients in this study were plotted versus patient age, with age binned into 5-year groups. The SARS-CoV-2 IgG index value is lowest in patients ages 16–40. The black dotted line is a regression line fitted to the data to show trends. (C) The mean SARS-CoV-2 IgG index values (AU/mL) of male SARS-CoV-2 IgG positive patients were plotted versus patient age, with age binned into 5-year groups. The SARS-CoV-2 IgG index value is lowest in patients ages 16 to 40. The black dotted line is a regression line fitted to the data to show trends. (D) The mean SARS-CoV-2 IgG index values (AU/mL) of female SARS-CoV-2 IgG positive patients were plotted versus patient age, with age binned into 5-year groups. The SARS-CoV-2 IgG index value is lowest in patients ages 16 to 35. The black dotted line is a regression line fitted to the data to show trends.