Assessment of the humoral response to the homologous Gam-COVID-Vac (Sputnik V) or heterologous Sputnik V/mRNA-1273 (Moderna) vaccination against SARS-CoV-2 in dialysis patients

Neutralizing antibody levels detected early after mRNA-based vaccination do not predict by themselves subsequent breakthrough infections of SARS-CoV-2

The development of mRNA vaccines represented a significant achievement in response to the global health crisis during the SARS-CoV-2 pandemic. Evaluating vaccine efficacy entails identifying different anti-SARS-CoV-2 antibodies, such as total antibodies against the Receptor Binding Domain (RBD) of the S-protein, or neutralizing antibodies (NAbs). This study utilized an innovative PETIA-based kit to measure NAb, and the investigation aimed to assess whether levels of anti-RBD IgG and NAb uniformly measured 30 days after vaccination could predict individuals at a higher risk of subsequent infection in the months following vaccination. Among a cohort of healthy vaccinated healthcare workers larger than 6,000, 12 mRNA-1273- and 115 BNT162b2-vaccinated individuals contracted infections after the first two doses. The main finding is that neither anti-RBD IgG nor NAb levels measured at day 30 post-vaccination can be used as predictors of breakthrough infections (BI). Therefore, the levels of anti-SARS-CoV-2 antibodies detected shortly after vaccination are not the pivotal factors involved in antiviral protection, and other characteristics must be considered in understanding protection against infection. Furthermore, the levels of anti-RBD and NAbs followed a very similar pattern, with a correlation coefficient of r = 0.96. This robust correlation would justify ceasing the quantification of NAbs, as the information provided by both determinations is highly similar. This optimization would help allocate resources more efficiently and speed up the determination of individuals' humoral immunity status.

Humoral and T Cell Response to SARS-CoV-2 Vaccination in Patients With Rheumatoid Arthritis

OBJECTIVE

The objective of this study was to assess the SARS-CoV-2-specific humoral and T cell response after a two-dose regimen of SARS-CoV-2 vaccine in patients with rheumatoid arthritis (RA).

METHODS

In this observational study, patients with RA who are ≥18 years of age and vaccinated for SARS-CoV-2 according to the Argentine National Health Ministry's vaccination strategy were included. Anti-SARS-CoV-2 immunoglobulin G (IgG) antibodies (ELISA-COVIDAR test), neutralizing activity (cytotoxicity in VERO cells), and specific T cell response (IFN-γ ELISpot Assay) were assessed after the first and second dose.

RESULTS

A total of 120 patients with RA were included. Mostly, homologous regimens were used, including Gam-COVID-Vac (27.5%), ChAdOx1 (24.2%), and BBIBP-CorV (22.5%). The most frequent combination was Gam-COVID-Vac/mRNA-1273 (21.7%). After the second dose, 81.7% presented with anti-SARS-CoV-2 antibodies, 70.0% presented with neutralizing activity, and 65.3% presented with specific T cell response. The use of BBIBP-CorV and treatment with abatacept (ABA) and rituximab (RTX) were associated with undetectable antibodies and no neutralizing activity after two doses. BBIBP-CorV was also associated with the absence of T cell response. The total incidence of adverse events was 357.1 events per 1,000 doses, significantly lower with BBIBP-CorV (166.7 events per 1,000 doses, P < 0.02).

CONCLUSION

In this RA cohort vaccinated with homologous and heterologous regimens against COVID-19, 2 out of 10 patients did not develop anti-SARS-CoV-2 IgG, 70% presented with neutralizing activity, and 65% presented with specific T cell response. The use of BBIBP-CorV was associated with deficient humoral and cellular response, whereas treatment with ABA and RTX resulted in an impaired anti-SARS-CoV-2 IgG formation and neutralizing activity.