Vitamin D-related Polymorphisms and Vitamin D Levels as Risk Biomarkers of COVID-19 Infection Severity (preprint)

Background: Vitamin D is a fundamental regulator of host defences by activating genes related to innate and adaptive immunity. Previous research shows a correlation between the levels of vitamin D in patients infected with SARS-CoV-2 and the degree of disease severity. This work investigates the impact of the genetic background related to vitamin D pathways on COVID-19 severity. For the first time, the Portuguese population was characterized regarding the prevalence of high impact variants in genes associated with the vitamin D pathways. Methods: This study enrolled 517 patients admitted to two tertiary Portuguese hospitals. The serum concentration of 25 (OH)D, was measured in the hospital at the time of patient admission. Genetic variants, 18 variants, in the genes AMDHD1, CYP2R1, CYP24A1, DHCR7, GC, SEC23A, and VDR were analysed. Results: The results show that polymorphisms in the vitamin D binding protein encoded by the GC gene are related to the infection severity (p = 0.005). There is an association between vitamin D polygenic risk score and the serum concentration of 25 (OH)D (p = 0.042). There is an association between 25 (OH)D levels and the survival and fatal outcomes (p = 1.5e-4). The Portuguese population has a higher prevalence of the DHCR7 RS12785878 variant when compared with its prevalence in the European population (19% versus 10%).Conclusion: This study shows a genetic susceptibility for vitamin D deficiency that might explain higher severity degrees in COVID-19 patients. These results reinforce the relevance of personalized strategies in the context of viral diseases.

Vitamin D-related polymorphisms and vitamin D levels as risk biomarkers of COVID-19 infection severity (preprint)

Background: Vitamin D is a fundamental regulator of host defences by activating genes related to innate and adaptive immunity. Previous research shows a correlation between the levels of vitamin D in patients infected with SARS-CoV-2 and the degree of disease severity. This work investigates the impact of the genetic background related to vitamin D pathways on COVID-19 severity. For the first time, the Portuguese population was characterized regarding the prevalence of high impact variants in genes associated with the vitamin D pathways. Methods: This study enrolled 517 patients admitted to two tertiary Portuguese hospitals. The serum concentration of 25 (OH)D, was measured in the hospital at the time of patient admission. Genetic variants, 18 variants, in the genes AMDHD1, CYP2R1, CYP24A1, DHCR7, GC, SEC23A, and VDR were analysed. Results: The results show that polymorphisms in the vitamin D binding protein encoded by the GC gene are related to the infection severity (p = 0.005). There is an association between vitamin D polygenic risk score and the serum concentration of 25 (OH)D (p = 0.042). There is an association between 25 (OH)D levels and the survival and fatal outcomes (p = 1.5e-4). The Portuguese population has a higher prevalence of the DHCR7 RS12785878 variant when compared with its prevalence in the European population (19% versus 10%). Conclusion: This study shows a genetic susceptibility for vitamin D deficiency that might explain higher severity degrees in COVID-19 patients. These results reinforce the relevance of personalized strategies in the context of viral diseases.

Prevalence of SARS-CoV-2 antibodies among workers of the public higher education institutions of Porto, Portugal (preprint)

Objectives: To assess the prevalence of SARS-CoV-2 specific immunoglobulin (Ig) M and IgG antibodies among workers of the three public higher education institutions of Porto, Portugal, from May to July 2020. Methods: A rapid point of care testing for specific IgM and IgG antibodies of SARS-CoV-2 was performed, and a questionnaire was applied to 4592 workers on a voluntary basis. We computed the apparent IgM, IgG, and combined IgM or IgG prevalence, along with the true prevalence and 95% credible intervals (95% CI) using Bayesian inference . Results: We found an apparent prevalence of 3.1% for IgM, 1.0% for IgG, and 3.9% for either antibody class. The estimated true prevalence was 2.0% (95% CI 0.1-4.3) for IgM, 0.6% (95% CI 0.0-1.3) for IgG and 2.5% (95% CI 0.1-5.3) for IgM or IgG. A SARS-CoV-2 molecular diagnosis was reported by 21 (0.5%) workers, and of these, 90.5% had a reactive IgG result. Seroprevalence was higher among those reporting known contacts with confirmed cases, having been quarantined, having a previous molecular negative test, or having had symptoms. Conclusions: We found a low seroprevalence among workers from the three public higher education institutions of Porto after the first wave of the SARS-CoV-2 infection. However, the estimated true seroprevalence was approximately five times higher than the reported SARS-CoV-2 infection using a molecular test.