Dramatic drop of new SARS-CoV-2 infections among health care workers after the first dose of the BNT162b2 mRNA Covid-19 Vaccine (preprint)

Objectives. To evaluate the effect of mRNA SARS-Cov-2 vaccination on the incidence of new SARS-CoV-2 infections in health care workers (HCW). Methods. The evolution of the incident rate of SARS-CoV-2 infection in a cohort of 2590 HCW after a mRNA SARS-CoV-2 vaccination, as compared to the rate in the community (n=170513). SARS-CoV-2 infections were microbiologically confirmed by an antigen, a CRP positive test, or both. Results. A total of 1820 HCW (70,3% of total) received the first dose of the vaccine between January 10-16, 2021), and 296 (11,4%) the following week. All of them completed vaccination 3 weeks later. New SARS-COV-2 infections in HCW declined by 62% at 2-4 weeks after the first dose of mRNA SARS-CoV-2 vaccination and virtually disappeared after the second dose of the vaccine. Vaccination rate was negligible for this time period in the community (<5%). The decline in the incident rate of SARS-COoV-2 new infection in HCW shortly after the administration of the first dose of the vaccine was strikingly higher than the reduction observed in the general population (p<0.001and became even more pronounced after the second dose of the vaccine (p<0.001). Conclusions. mRNA SARS-CoV-2 vaccination is associated with a dramatic decline in new SARS-CoV-2 infection among HCW, even before the administration of the second dose of the vaccine.

Impact of previous COVID-19 on immune response after a single dose of BNT162b2 SARS-CoV-2 vaccine (preprint)

Immune response after a single-dose of BNT162b2 vaccine is markedly increased in health care workers with previous SARS-CoV2 exposure, as assessed by positive SARS-CoV2 IgG, particularly after moderate-severe COVID-19. These data may inform the priority of the boosting mRNA second dose in times of vaccine shortage.

Does Biological Therapy Protect against Severe COVID-19? (preprint)

Objective. To estimate COVID-19 infection incidence rate with severe affectation (requiring hospitalization) in patients with biological treatment due to rheumatoid arthritis (RA), psoriatic arthritis (PsA), spondyloarthritis (SpA), psoriasis (Ps), and inflammatory bowel disease (IBD) and compare it with incidence rate in the general population. Methods: Retrospective observational study based on information provided by two administrative databases. One of these two databases contains information on all patients seen in our hospital and diagnosed with COVID-19 infection between March 4th 2020 and April 26th 2020. The other database contains data from patients seen at Rheumatology, Dermatology and Digestive Departments in our hospital who are currently receiving biological therapy. We calculated the crude and age and sex adjusted incidence in both groups. To compare both groups we calculated the Incidence Rate Ratio. Results: There was a total of 2,182 patients with COVID-19 requiring hospitalization. Four patients out of a total of 797 patients receiving biological therapy had contracted COVID-19 and required hospital care. Crude incidence rate of COVID-19 requiring hospital care among the general population was 1.41%, and it was 0.50% among the group receiving biological therapy. Rates adjusted by age and sex in the biological group was 0.45% (CI95% 0.11-4.13). The IRR of the group receiving biological therapy compared to the general population was 0.39 (CI95% 0.14-1, p=0.049). Conclusion: Findings suggest that prior use of biological therapy does not associate with severe manifestations of COVID-19, and it is likely to have a protective effect against them when compared to the general population.

Increased risk for COVID-19 among Migrants from Latin-America, Caribbean, and Sub-Saharan Africa living in Spain (preprint)

Little is known regarding the relevance of racial / ethnic background on the risk of COVID-IO infection, particularly in Europe. We evaluated the risk for COVID-19 among migrants from different areas of the world within a context of universal free access to medical care. We conducted a population-based cohort analysis of the cumulative incidence of PCR-confirmed COVID-19 among adult residents at Alcorcon (Spain) in the first wave of the disease. The crude cumulative incidence among migrants (n=20419) was higher than among Spaniards (n=131599): 8.81 and 6.51 and per 1000 inhabitants respectively (p<0.001) but differed by world region of origin. By negative binomial regression, adjusted for age and sex, relative risks (RR) for COVID-19 were not significantly different from Spaniards for individuals from Europe, Asia or Northern Africa. In contrast, there was a marked increased risk for Sub-Saharan Africa (RR 3.66, 95% confidence interval (Cl) 42-9.41, p=0.007), Caribbean (RR6.35, 95% Cl 3.83-10.55, p<0.001) and Latin-America (RR6.92, 95% Cl 4.49-10.67, p <0.001). Migrants from these areas of the world may deserve a closer attention both for clinical and epidemiological reasons.