The effectiveness of primary series CoronaVac vaccine in preventing COVID-19 illness: A prospective cohort study among healthcare workers in Azerbaijan, May-November 2021.

Background: Healthcare workers (HCWs) have suffered considerable morbidity and mortality during the COVID-19 pandemic. Few studies have evaluated the CoronaVac vaccine effectiveness (VE), particularly in Eastern Europe, where the vaccine has been widely used. Methods: We conducted a prospective cohort study among HCWs in seven hospitals in Baku, Azerbaijan between May 17 and November 30, 2021, to evaluate primary series (two-dose) CoronaVac VE against symptomatic SARS-CoV-2 infection. Participants completed weekly symptom questionnaires, provided nasopharyngeal swabs for SARS-CoV-2 RT-PCR testing when symptomatic, and provided serology samples at enrollment that were tested for anti-spike and anti-nucleocapsid antibodies. We estimated VE as (1 - hazard ratio)*100 using a Cox proportional hazards model with vaccination status as a time-varying exposure, adjusting for hospital and previous SARS-CoV-2 infection status. Results: We enrolled 1582 HCWs. At enrollment, 1040 (66%) had received two doses of CoronaVac; 421 (27%) were unvaccinated. During the study period, 72 PCR-positive SARS-CoV-2 infections occurred; 36/39 (92%) sequenced samples were classified as Delta variants. Primary series VE against COVID-19 illness was 29% (95% CI: -51%; 67%) for the entire analysis period. For the Delta-only period (July 1-November 30, 2021), primary series VE was 19% (95% CI: -81%; 64%). For the entire analysis period, primary series VE was 39% (95% CI: -40%; 73%) for HCWs vaccinated within 14-149 days and 19% (95% CI: -81%; 63%) for those vaccinated ≥150 days. Conclusions: During a period in Azerbaijan characterized by mostly Delta circulation, VE point estimates suggested that primary series CoronaVac protected nearly 1 in 3 HCWs against COVID-19, but 95% confidence intervals were wide, with lower bounds that crossed zero, reflecting the limited precision of our VE estimates. Our findings underscore the need to consider booster doses for individuals who have received the primary series of CoronaVac.

Factors associated with early uptake of COVID-19 vaccination among healthcare workers in Azerbaijan, 2021.

INTRODUCTION: We evaluated uptake and factors associated with COVID-19 vaccination among health workers (HWs) in Azerbaijan. RESULTS: Among 1575 HWs, 73% had received at least one dose, and 67% received two doses; all received CoronaVac. Factors associated with vaccination uptake included no previous COVID-19 infection, older age, belief in the vaccine's safety, previous vaccination for influenza, having patient-facing roles and good or excellent health by self-assessment. CONCLUSION: These findings could inform strategies to increase vaccination uptake as the campaign continues.

Rotavirus gastroenteritis surveillance in Azerbaijan, 2011-2016.

INTRODUCTION: Rotavirus is a leading cause of acute gastroenteritis and mortality among children worldwide but data describing rotavirus disease in Azerbaijan are lacking. This analysis describes the rotavirus disease burden in Baku, the largest city in Azerbaijan. METHODS: We conducted active, prospective, sentinel hospital surveillance with laboratory confirmation for rotavirus among children under 5 years of age hospitalized at a large pediatric hospital in Baku during 2011-2016. Children with bloody diarrhea, or prior use of antibiotics or intravenous fluids were excluded. The guardians of enrolled children completed a questionnaire documenting clinical and demographic information. A stool specimen was collected from each enrolled child. We report the number and proportion of rotavirus positive hospitalizations during the surveillance period and a clinical description of rotavirus-positive and rotavirus-negative children. RESULTS: From July 2011 through June 2016, 3139 children <5 years of age were enrolled into the surveillance system. Of these, 523 (17%) were positive for rotavirus, varying from 13% to 21% by surveillance year, with a median of 16% over the surveillance period. Increase in rotavirus detections occurred during December-May. Most rotavirus infections (303/523; 58%) occurred in children aged 6-23 months. CONCLUSION: Rotavirus is responsible for approximately 16% of annual hospital admissions for acute gastroenteritis in children <5 years of age in Baku. This is lower than regional estimates. Exclusion of children with a history of antibiotic use or intravenous fluids may be accounting for this lower prevalence, and expansion of surveillance to include these groups could provide a more comprehensive picture of acute rotavirus gastroenteritis in Baku.