Clinical Variables Correlate with Serum Neutralizing Antibody Titers after COVID-19 mRNA Vaccination in an Adult, US-based Population

Sex differences in the efficacy and safety of SARS-CoV-2 vaccination in residents of long-term care facilities: insights from the GeroCovid Vax study

Despite the reported sex-related variations in the immune response to vaccination, whether the effects of SARS-CoV-2 vaccination differ by sex is still under debate, especially considering old vulnerable individuals, such as long-term care facilities (LTCFs) residents. This study aimed to evaluate COVID-19 infections, adverse events, and humoral response after vaccination in a sample of LTCF residents. A total of 3259 LTCF residents (71% females; mean age: 83.4 ± 9.2 years) were enrolled in the Italian-based multicenter GeroCovid Vax study. We recorded the adverse effects occurring during the 7 days after vaccine doses and COVID-19 cases over 12 months post-vaccination. In a subsample of 524 residents (69% females), pre- and post-vaccination SARS-CoV-2 trimeric S immunoglobulin G (Anti-S-IgG) were measured through chemiluminescent assays at different time points. Only 12.1% of vaccinated residents got COVID-19 during the follow-up, without any sex differences. Female residents were more likely to have local adverse effects after the first dose (13.3% vs. 10.2%, p = 0.018). No other sex differences in systemic adverse effects and for the following doses were recorded, as well as in anti-S-IgG titer over time. Among the factors modifying the 12-month anti-S-IgG titers, mobility limitations and depressive disorder were more likely to be associated with higher and lower levels in the antibody response, respectively; a significantly lower antibody titer was observed in males with cardiovascular diseases and in females with diabetes or cognitive disorders. The study suggests that, among LTCF residents, SARS-CoV-2 vaccination was effective regardless of sex, yet sex-specific comorbidities influenced the antibody response. Local adverse reactions were more common in females.

Anti-SARS-CoV-2 IgG Antibody Response in Individuals Infected Post Complete Vaccination: A 6-Month Longitudinal Study in Healthcare Professionals

Serological assays have been used to evaluate the magnitude of naturally acquired and BNT162b2 vaccine-induced immunity. In order to assess the extent to which the antibody response correlates with infection-mediated protection after vaccination, we investigated the kinetics of anti-SARS-CoV-2-S1 IgG in fully vaccinated healthy individuals who did or did not develop COVID-19 within 8 months after the booster dose. The anti-SARS-CoV-2-S1 receptor-binding, domain-specific IgG titer was assessed in serum samples collected at various intervals from 4 months after the second and 6 months after the third dose. The IgG level decreased 33% within 6 months after the second dose and, one month after the third dose, increased dramatically (>300%) compared with the pre-booster time point. COVID-19 infection within two months after the third dose did not cause significant IgG variation, but later viral infections elicited an IgG response similar to the initial response to the booster. The probability of developing COVID-19 and the severity of symptoms were not related to the antibody titer. Our data indicate that repeated exposure to viral antigens by either vaccination or infection at short-term intervals elicits limited boosting effects and that an IgG titer alone is not associated with the prediction of future infections and their symptomatology.

Reduced early response to SARS-CoV2 vaccination in people with type 1 and type 2 diabetes, a 6 months follow-up study: The CoVaDiab study I

INTRODUCTION

Diabetes mellitus worsens the prognosis of SARS-CoV-2 infection, and vaccination has been the major tool for reducing the risk of hospitalisation, and mortality. The primary aim of this study was to evaluate the response to the SARS-CoV-2 vaccine in subjects with diabetes and controls. Differences between type 1 (T1D) and type 2 (T2D) diabetes and clinical determinants of vaccination response were also evaluated.

METHODS

128 subjects with diabetes (60 with T1D and 62 with T2D) and 202 subjects acting as controls who completed a full vaccination cycle with two doses of mRNA vaccine were enroled. People with previous SARS-CoV-2 infection were excluded. Antibodies (Ab) directed against the spike protein of the SARS-CoV-2 were evaluated at one and 6 months after vaccination.

RESULTS

In the whole cohort, the Ab level was higher among women than in men (p = 0.011) and negatively correlated with age (rho = -0.155, p = 0.005). Subjects with diabetes showed decreased levels of Ab after one month compared to controls (1217[747-1887]BAU/mL vs. 1477[942-2556]BAU/mL, p = 0.002), even after correction for age and gender (p = 0.002). No difference was found between subjects with T1D and T2D. After 6 months, antibody levels significantly decreased in people with and without diabetes, with no differences between groups, although some subjects were lost at follow-up. In subjects with diabetes, only a significant correlation was found between Ab level and renal function (rho 0.190, p = 0.042).

CONCLUSIONS

Both T1D and T2D are associated with a reduced early response to vaccination. The serum concentration of Ab significantly reduced over time in both groups, highlighting the relevance of vaccination boosters independently of the presence of diabetes.