Longitudinal humoral antibody response to SARS-CoV-2 infection among healthcare workers in a New York City hospital.

OBJECTIVE: Dynamics of humoral immune responses to SARS-CoV-2 antigens following infection suggest an initial decay of antibody followed by subsequent stabilisation. We aim to understand the longitudinal humoral responses to SARS-CoV-2 nucleocapsid (N) protein and spike (S) protein and to evaluate their correlation to clinical symptoms among healthcare workers (HCWs). DESIGN: A prospective longitudinal study. SETTING: This study was conducted in a New York City public hospital in the South Bronx, New York. PARTICIPANTS: HCWs participated in phase 1 (N=500) and were followed up 4 months later in phase 2 (N=178) of the study. They underwent SARS-CoV-2 PCR and serology testing for N and S protein antibodies, in addition to completion of an online survey in both phases. Analysis was performed on the 178 participants who participated in both phases of the study. PRIMARY OUTCOME MEASURE: Evaluate longitudinal humoral responses to viral N (qualitative serology testing) and S protein (quantitative Mount Sinai Health System ELISA to detect receptor-binding domain and full-length S reactive antibodies) by measuring rate of decay. RESULTS: Anti-N antibody positivity was 27% and anti-S positivity was 28% in phase 1. In phase 1, anti-S titres were higher in symptomatic (6754 (5177-8812)) than in asymptomatic positive subjects (5803 (2825-11 920)). Marginally higher titres (2382 (1494-3797)) were seen in asymptomatic compared with the symptomatic positive subgroup (2198 (1753-2755)) in phase 2. A positive correlation was noted between age (R=0.269, p<0.01), number (R=0.310, p<0.01) and duration of symptoms (R=0.434, p<0.01), and phase 1 anti-S antibody titre. A strong correlation (R=0.898, p<0.001) was observed between phase 1 titres and decay of anti-S antibody titres between the two phases. Significant correlation with rate of decay was also noted with fever (R=0.428, p<0.001), gastrointestinal symptoms (R=0.340, p<0.05), and total number (R=0.357, p<0.01) and duration of COVID-19 symptoms (R=0.469, p<0.001). CONCLUSIONS: Higher initial anti-S antibody titres were associated with larger number and longer duration of symptoms as well as a faster decay between the two time points.

Acute Immune Thrombocytopenia (ITP) Following COVID-19 Vaccination in a Patient With Previously Stable ITP.

Immune thrombocytopenia (ITP) is an autoimmune condition associated with multiple risk factors including viral infections (hepatitis B virus/hepatitis C virus/cytomegalovirus, HIV, and recently severe acute respiratory syndrome coronavirus 2) and vaccines. Though immune mechanisms have been proposed to explain the pathogenesis of acute ITP, autoimmunity with the coronavirus disease 2019 (COVID-19) vaccine is still unclear and needs further research. We report a case of acute ITP after administration of the Pfizer-BioNTech mRNA COVID-19 vaccine in a patient with previously stable ITP.

SARS-CoV-2 seroprevalence among health care workers in a New York City hospital: A cross-sectional analysis during the COVID-19 pandemic.

BACKGROUND: New York City (NYC) has endured the greatest burden of COVID-19 infections in the US. Health inequities in South Bronx predisposed this community to a large number of infectious cases, hospitalizations, and mortality. Health care workers (HCWs) are at a high risk of exposure to the infection. This study aims to assess seroprevalence and the associated characteristics of consenting HCWs from an NYC public hospital. METHODS: This cross-sectional study includes serum samples for qualitative SARS-CoV-2 antibody testing with nasopharyngeal swabs for SARS-CoV-2; PCR and completion of an online survey capturing demographics, COVID-19 symptoms during the preceding months on duty, details of healthcare and community exposure, and travel history were collected from consenting participants in May 2020. Participants' risk of exposure to COVID-19 infection in the hospital and in the community was defined based on CDC guidelines. Travel history to high-risk areas was also considered an additional risk. The Odds Ratio with bivariable and multivariable logistic regression was used to assess characteristics associated with seroprevalence. RESULTS: A total of 500 HCW were tested, 137 (27%) tested positive for the SARS-CoV-2 antibody. Symptomatic participants had a 75% rate of seroconversion compared to those without symptoms. Subjects with anosmia and ageusia had increased odds of seroconversion in comparison to those without these symptoms. Community exposure was 34% among those who had positive antibodies. CONCLUSION: Seroprevalence among HCWs was high compared to the community at the epicenter of the pandemic. Further studies to evaluate sustained adaptive immunity in this high-risk group will guide our response to a future surge.