Exposure to COVID-19 among unvaccinated healthcare personnel and risk for infection: a single-center retrospective study.

INTRODUCTION: Characteristics of exposure and infection risk, are important in strategy development for infection control among healthcare workers (HCWs). Our objective was to investigate the characteristics of exposure of HCWs to SARS-CoV-2 and determine the risk of COVID-19 development. METHODOLOGY: This is a retrospective single-center cohort study, conducted between March and December 2020. Unvaccinated and exposed HCWs were asked to complete a standard form, including demographic data and characteristics of exposure(s). Exposures were stratified according to national guidelines. STROBE checklist was used. RESULTS: Among a total of 4,385 healthcare workers, 1,483 HCWs (33.8%) with a total of 1,903 exposures to SARS-CoV-2 were identified. Median age was 31 (IQR: 26-40) years and 45.4% were male (N = 673). Following exposure, 78 HCWs became SARS-CoV-2-positive (attack rate: 3.9%) and secondary attack rate was 4/16. In terms of infection, exposure to SARS-CoV-2-positive HCWs posed a greater risk compared to contact with patients (8.9%, [n = 66] vs. 3.8% [n = 12], respectively, p = 0.003). PCR positivity rates were 11.5%, 6.3%, and 8.4% for low, medium, and high-risk contacts (p = 0.152). Median time to infection post-exposure was 7 (IQR: 4-13) days. CONCLUSIONS: Given the attack rates, there was no correlation between risk levels and PCR test positivity rates. There was no difference between HCWs with or without work restrictions, in terms of PCR positivity. Due to feasibility issues, prioritizing universally applied symptom screening and resource control strategies and suspending contact tracing and work restrictions, appear to be safe during high prevalence period.

Rickettsia sibirica mongolitimonae Infection, Turkey, 2016.

In 2016, Rickettsia sibirica mongolitimonae was diagnosed for a man in Turkey. He had been bitten by a Hyalomma marginatum tick, from which PCR detected rickettsial DNA. Sequence analysis of the DNA identified R. sibirica mongolitimonae. Immunofluorescence assay of patient serum indicated R. conorii, which cross-reacts. PCR is recommended for rickettsiosis diagnoses.

Comparison of the accelerated and classic vaccination schedules against Hepatitis B: three-week Hepatitis B vaccination schedule provides immediate and protective immunity.

BACKGROUND: Hepatitis B virus infection although preventable by vaccination remains an important health issue throughout the world due to its morbidity, mortality and economical losses. Early seroprotection is desirable for people at high risk of exposure. The aim of this study was to determine whether three-week hepatitis B vaccination (on days 0, 10 and 21) provide seroprotection or not. METHODS: The 120 subjects enrolled into the study were divided into two groups and vaccinated by the classic (months 0, 1, and 2) or the accelerated (days 0, 10, and 21) schedules and antibody response determined on days 30, 60, and 90 and, if below 10 mIU/ml(-1), again on day 180. For each individual in the classic group (B) three subjects were enrolled in the accelerated group (A). Recombinant hepatitis B vaccine (Gen-Hevac B, Pasteur) was given as 20 micrograms intramuscular injections via the deltoid muscle. A booster dose on day 365 was administered for each group. Family members of hepatitis B carriers and volunteer health personnel were enrolled into group A. To the B group only volunteers who wanted vaccination against hepatitis B were included. RESULTS: After three doses of vaccine, Anti-HBs titers reached protective levels in both groups. The number of vaccinees with seroprotective levels of Anti-HBs (> or =10 mIU/ml(-1)) on day 30 was 53 (58.9%) in group A and 9 (30.0%) in group B (p < 0.05). On day 60, there was no difference between group A and B, with response rates of 84.4% (n = 76) and 80.0% (n = 24) respectively (p > 0.05). On day 90 there was no difference between group B and group A; with 26 (86.7%) and 79 (87.7%) responders respectively. In both groups those with Anti-HBs levels <10 mIU/ml(-1) attained protective levels by day 180. CONCLUSION: In this study, the three-week vaccination provided protective antibody titers within a shorter time compared to the classic schedule. Therefore, in order to provide rapid antibody production against hepatitis B virus, the accelerated vaccination schedule seems to be a good preference.