A hidden immune feature may have spared unvaccinated people from COVID-19 infections - Interesting Engineering

According to the results of the study published in the European Journal of Immunology, a third of the care workers developed antibodies to COVID-19, and they fell into two distinct groups based on antibody patterns and COVID-19 incidence.

The patterns of humoral and cellular responses to SARS-CoV-2 were studied in Swedish primary health care workers (n = 156) for 6 months during the Covid-19 pandemic.

Serum IgA and IgG to SARS-CoV-2, T-cell proliferation and cytokine secretion, demographic and clinical data, PCR-verified infection, and self-reported symptoms were monitored.

The multivariate method OPLS-DA was used to identify immune response patterns coupled to protection from Covid-19.

Contracting Covid-19 was associated with SARS-CoV-2-specific neutralizing serum IgG, T cell, IFN-γ, and granzyme B responses to SARS-CoV-2, self-reported typical Covid-19 symptoms, male sex, higher BMI, and hypertension.

Not contracting Covid-19 was associated with female sex, IgA-dominated, or no antibody responses to SARS-CoV-2, airborne allergy, and smoking.

To conclude, serum IgG-dominated responses correlated with T-cell responses to SARS-CoV-2 and PCR-confirmed Covid-19, whereas IgA-dominated responses correlated with not contracting the infection