RESUMO
SARS-CoV-2 vaccination is known to induce antibodies that recognize also variants of concerns (VoCs) of the virus. However, epidemiological and laboratory evidences indicate that these antibodies have a reduce neutralization ability against VoCs. We studied binding and neutralizing antibodies against the Spike RBD and S2 domains of the Wuhan-Hu-1 virus and its alpha and beta VoCs and of seasonal betacoronaviruses (HKU1 and OC43) in a cohort of 31 health care workers vaccinated with BNT162b2-Comirnaty and prospectively followed post-vaccination. The study of sequential samples collected up to 64 days post-vaccination showed that serological assays measuring IgG against Wuhan-Hu-1 antigens were a poor proxy for VoCs neutralization. In addition, in subjects who had asymptomatic or mild COVID-19 prior to vaccination the loss of nAbs following disease can be rapid and protection from re-infection post-vaccination is often no better than in naive subjects. Interestingly, in health care workers naive for SARS-CoV-2 infection, vaccination induced a rapid and transient reactivation of pre-existing seasonal coronaviruses IgG responses that was associated with a subsequent reduced ability to neutralize some VoCs.
RESUMO
Understanding how antibody to SARS-CoV-2 evolve during infection may provide important insight into therapeutic approaches to prevent fatal COVID-19 illness and vaccines. Here, we profile the antibody response of 162 well-characterized COVID-19 symptomatic patients followed longitudinally for up to eight months from symptom onset. Using two newly developed assays we detect SARS-CoV-2 neutralization and antibodies binding to Spike antigens and nucleoprotein as well as to Spike S2 antigen of seasonal beta-coronaviruses, and to hemagglutinin of the H1N1 flu virus. Presence of neutralizing antibodies withing the first weeks from symptom onset correlates with time to a negative swab result (p=0.002) while lack of neutralization with an increased risk of a fatal disease outcome (HR 2.918, 95%CI 1.321-6.449; p=0.008). Neutralizing antibody titers progressively drop after 5-8 weeks but are still detectable up to 8 months in the majority of recovered patients regardless of age or co-morbidities. IgG to Spike antigens are the best correlate of neutralization. Antibody responses to seasonal coronaviruses are temporary boosted and parallel those to SARS-CoV-2 without dampening the specific response or worsening disease progression. Thus, a compromised immune response to the Spike rather than an enhanced one is a major trait of patients with critical conditions. Patients should be promptly identified and immediately start therapeutic interventions aimed at restoring their immunity.
