Serological responses to SARS-CoV-2 following non-hospitalised infection: clinical and ethnodemographic features associated with the magnitude of the antibody response

Abstract

ObjectiveTo determine clinical and ethnodemographic correlates of serological responses against the SARS-CoV-2 spike glycoprotein following mild-to-moderate COVID-19.DesignA retrospective cohort study of healthcare workers who had self-isolated due to COVID-19.SettingUniversity Hospitals Birmingham NHS Foundation Trust, UK (UHBFT).Participants956 healthcare workers were recruited by open invitation via UHBFT trust email and social media between 27 April 2020 and the 8 June 2020.InterventionParticipants volunteered a venous blood sample that was tested for the presence of anti-SARS-CoV-2 spike glycoprotein antibodies. Results were interpreted in the context of the symptoms of their original illness and ethnodemographic variables.ResultsUsing an assay that simultaneously measures the combined IgG, IgA and IgM response against the spike glycoprotein (IgGAM), the overall seroprevalence within this cohort was 46.2% (n=442/956). The seroprevalence of immunoglobulin isotypes was 36.3%, 18.7% and 8.1% for IgG, IgA and IgM, respectively. IgGAM identified serological responses in 40.6% (n=52/128) of symptomatic individuals who reported a negative SARS-CoV-2 PCR test. Increasing age, non-white ethnicity and obesity were independently associated with greater IgG antibody response against the spike glycoprotein. Self-reported fever and fatigue were associated with greater IgG and IgA responses against the spike glycoprotein. The combination of fever and/or cough and/or anosmia had a positive predictive value of 92.3% for seropositivity in self-isolating individuals a time when Wuhan strain SARS-CoV-2 was predominant.Conclusions and relevanceAssays employing combined antibody detection demonstrate enhanced seroepidemiological sensitivity and can detect prior viral exposure even when PCR swabs have been negative. We demonstrate an association between known ethnodemographic risk factors associated with mortality from COVID-19 and the magnitude of serological responses in mild-to-moderate disease.

Determinants of IgG antibodies kinetics after severe and critical COVID‐19

“…A striking finding of our analysis is the association of age and obesity with higher IgG titers. This may appear counterintuitive, as both factors are usually thought to associate with poor adaptive immune response, 18,19 but confirms similar findings for age 4,16,[20][21][22][23] and obesity 4,21,22 after COVID-19. Although absolute IgG levels have been shown to positively correlate with age, a decreased capacity of humoral response to novel antigens has been shown in elderlies, linked to a decreased naïve B cell repertoire.…”

Relationship between Acute-Phase Symptoms and Immunoglobulin G Seropositivity up to Eight Months after COVID-19

“…Since almost all symptomatic subjects experience more than one symptom, combinations of symptoms need to be evaluated too. A British seroprevalence study among 956 HCWs detected that the combination of fever and/or cough and/or anosmia had a positive predictive value of 92.3% for seropositivity [19]. The present study identified two statistically significant symptom clusters (associated with dyspnea) (Figure 2).…”

Antibody responses and correlates of protection in the general population after two doses of the ChAdOx1 or BNT162b2 vaccines

“…We also found that those reporting non-white ethnicity had higher IgG peak levels. Non-white ethnicity has also been previously associated with higher antibody levels after natural infection 16 , 35 , 36 ; these findings could be due to genetic or societal differences or differential rates of undetected prior infection. Long-term health conditions were associated with lower peak levels and shorter half-lives for both vaccines.…”