Evaluation of the novel DiaSorin LIAISON ® Campylobacter assay for the rapid detection of Campylobacter spp

SARS-CoV-2 Infection-Blocking Immunity Post Natural Infection: The Role of Vitamin D

OBJECTIVE AND AIM

The extent of the protection against SARS-CoV-2 conferred by natural infection is unclear. Vitamin D may have a role in the interplay between SARS-CoV-2 infection and the evolving acquired immunity against it. We tested the correlation between baseline 25(OH) D content and both the reinfection rate and the anti-spike protein antibody titer following COVID-19 infection. Methods A retrospective observational survey that included a large convalescent COVID-19 population of subjects insured by the Leumit HMO was recorded between 1 February 2020 and 30 January 2022. Inclusion criteria required at least one available 25(OH)D level prior to enlistment. The association between 25(OH)D levels, the rate of breakthrough infection, and the anti-spike protein antibody titer was evaluated. Results A total of 10,132 COVID-19 convalescent subjects were included, of whom 322 (3.3%) sustained reinfection within a one-year follow-up. In the first 8 months after recovery, the reinfected patients were characterized by a higher incidence of low 25(OH)D levels (<30 ng/mL, 92% vs. 84.8%, p < 0.05), while during the following three months, the incidence of low 25(OH)D levels was non-significantly higher among PCR-negative convalescent subjects compared to those reinfected (86% vs. 81.7, p = 0.15). By multivariate analysis, age > 44 years (OR-0.39, 95% CI: 0.173-0.87, p = 0.02) and anti-spike protein antibody titer > 50 AU/mL (0.49, 95% CI: 0.25-0.96, p = 0.04) were inversely related to reinfection. No consistent correlation with vitamin D levels was observed among the 3351 available anti-spike protein antibody titers of convalescent subjects. However, the median anti-spike protein antibody titers tended to increase over time in the vitamin D-deficient group. Conclusion Higher pre-infection 25(OH)D level correlated with protective COVID-19 immunity during the first 8 months following COVID-19 infection, which could not be explained by anti-spike protein antibody titers. This effect dissipated beyond this period, demonstrating a biphasic 25(OH)D association that warrants future studies.

Low plasma 25(OH) vitamin D level is associated with increased risk of COVID-19 infection: an Israeli population-based study

Vitamin D deficiency is a worldwide pandemic. The aim of this study was to evaluate associations of plasma 25(OH)D levels with the likelihood of coronavirus disease 2019 (COVID‐19) infection and hospitalization. The study population included the 14 000 members of Leumit Health Services, who were tested for COVID‐19 infection from February 1^st to April 30^th, 2020, and who had at least one previous blood test for the plasma 25(OH)D level. ‘Suboptimal’ or ‘low’ plasma 25(OH)D level was defined as plasma 25‐hydroxyvitamin D, or 25(OH)D, concentration below the level of 30 ng/mL. Of 7807 individuals, 782 (10.02%) were COVID‐19‐positive, and 7025 (89.98%) COVID‐19‐negative. The mean plasma vitamin D level was significantly lower among those who tested positive than negative for COVID‐19 [19.00 ng/mL (95% confidence interval (CI) 18.41–19.59) vs. 20.55 (95% CI: 20.32–20.78)]. Univariate analysis demonstrated an association between the low plasma 25(OH)D level and increased likelihood of COVID‐19 infection [crude odds ratio (OR) of 1.58 (95% CI: 1.24–2.01, P < 0.001)], and of hospitalization due to the SARS‐CoV‐2 virus [crude OR of 2.09 (95% CI: 1.01–4.30, P < 0.05)]. In multivariate analyses that controlled for demographic variables, and psychiatric and somatic disorders, the adjusted OR of COVID‐19 infection [1.45 (95% CI: 1.08–1.95, P < 0.001)] and of hospitalization due to the SARS‐CoV‐2 virus [1.95 (95% CI: 0.98–4.845, P = 0.061)] were preserved. In the multivariate analyses, age over 50 years, male gender and low–medium socioeconomic status were also positively associated with the risk of COVID‐19 infection; age over 50 years was positively associated with the likelihood of hospitalization due to COVID‐19. We concluded that low plasma 25(OH)D levels appear to be an independent risk factor for COVID‐19 infection and hospitalization.