INTRODUCTION:Understanding COVID-19 vaccine effectiveness (VE) in healthcare workers (HCWs) is critical to inform vaccination policies. We measured COVID-19 VE against laboratory-confirmed symptomatic infection in HCWs in the country of Georgia from January - June 2022, during a period of Omicron circulation. METHODS:We conducted a cohort study of HCWs in six hospitals in Georgia. HCWs were enrolled in early 2021. Participants completed weekly symptom questionnaires. Symptomatic HCWs were tested by RT-PCR and/or rapid antigen test (RAT). Participants were also routinely tested, at varying frequencies during the study period, for SARS-CoV-2 by RT-PCR or RAT, regardless of symptoms. Serology was collected quarterly throughout the study and tested by electrochemiluminescence immunoassay for SARS-CoV-2 antibodies. We estimated absolute and relative VE of a first booster dose compared to a primary vaccine series as (1-hazard ratio)*100 using Cox proportional hazards models. RESULTS:Among 1253 HCWs, 141 (11%) received a primary vaccine series (PVS) and a first booster, 855 (68%) received PVS only, and 248 (20%) were unvaccinated. Most boosters were BNT162b2 (Comirnaty original monovalent) vaccine (90%) and BBIBP-CorV vaccine (Sinopharm) (9%). Most PVS were BNT162b2 vaccine (68%) and BBIBP-CorV vaccine (24%). Absolute VE for a first booster was 40% (95% Confidence Interval (CI) -56-77) at 7-29 days following vaccination, -9% (95% CI -104-42) at 30-59 days following vaccination, and -46% (95% CI -156-17) at ≥ 60 days following vaccination. Relative VE of first booster dose compared to PVS was 58% (95% CI 1-82) at 7-29 days following vaccination, 21% (95% CI -33-54) at 30-59 days following vaccination, and -9% (95% CI -82-34) at ≥ 60 days following vaccination. CONCLUSION:In Georgia, first booster dose VE against symptomatic SARS-CoV-2 infection among HCWs was moderately effective but waned very quickly during Omicron. Increased efforts to vaccinate priority groups in Georgia, such as healthcare workers, prior to periods of anticipated high COVID-19 incidence are essential.

Background Healthcare workers (HCWs) have suffered considerable morbidity and mortality during the COVID-19 pandemic. Few data on COVID-19 vaccine effectiveness (VE) are available from middle-income countries in Europe. We evaluated primary series COVID-19 VE against laboratory-confirmed COVID-19 among HCWs in Georgia. Methods HCWs in six hospitals in Georgia were invited to enroll in a prospective cohort study conducted during March 19–December 5, 2021. Participants completed weekly symptom questionnaires. Symptomatic HCWs were tested by RT-PCR and/or rapid antigen test (RAT), and participants were routinely tested for SARS-CoV-2 by RT-PCR or RAT, regardless of symptoms. Serology was collected at enrolment, and quarterly thereafter, and tested by electrochemiluminescence immunoassay for SARS-CoV-2 antibodies. We defined primary series vaccination as two doses of COVID-19 vaccine received ≥14 days before symptom onset. We estimated VE as (1-hazard ratio)*100 using a Cox proportional hazards model with vaccination status as a time-varying covariate. Estimates were adjusted by potential confounders that changed the VE estimate by more than 5%, according to the change-in-estimate approach. Results Overall, 1561/3849 (41%) eligible HCWs enrolled and were included in the analysis. The median age was 40 (IQR: 30-53), 1318 (84%) were female, and 1003 (64%) had laboratory evidence of prior SARS-Cov-2 infection. At enrolment, 1300 (83%) were unvaccinated; By study end, 1082 (62%) had completed a primary vaccine series (69% BNT162b2 (Pfizer-BioNTech); 22% BBIBP-CorV (Sinopharm); 9% other). During the study period, 191(12%) participants had a new PCR- or RAT-confirmed symptomatic SARS-CoV-2 infection. VEa gainst PCR- or RAT- confirmed symptomatic SARS-CoV-2 infection was 58 (95%CI: 41; 70) for all primary series vaccinations, 68% (95%CI: 51; 79) for BNT162b2, and 40% (95%CI: 1; 64) for BBIBP-CorV vaccines. Among previously infected HCWs, VE was 58% (95%CI: 11; 80). VE against medically attended COVID-19 was 52% (95%CI: 28; 68), and VE against hospitalization was 69% (95% CI: 36; 85). During the period of predominant Delta variant circulation (July-December 2021), VE against symptomatic COVID-19 was 52% (95%CI: 30; 66). Conclusions Primary series vaccination with BNT162b2 and BBIBP-CorV was effective at preventing COVID-19 among HCWs, most of whom had previous infection, during a period of mainly Delta circulation. Our results support the utility of COVID-19 primary vaccine series, and the importance of increasing coverage, even among previously infected individuals.

Among Azerbaijani healthcare workers (HCWs), compared to primary vaccine series, CoronaVac booster relative vaccine effectiveness was 60% (95% CI:25-79) and 79% (95% CI:44-92) against symptomatic and medically attended illness, respectively, during an Omicron BA.1/BA.2 period. Our results support timely CoronaVac booster uptake among Azerbaijani HCWs to reduce morbidity.

Background:Healthcare workers have experienced high rates of morbidity and mortality from coronavirus disease 2019 (COVID-19). Methods:A prospective cohort study was conducted in three Albanian hospitals between 19 February and 14 December 2021. All participants underwent polymerase chain reaction (PCR) and serological testing at enrolment, regular serology throughout, and PCR testing when symptomatic.Vaccine effectiveness (VE) against COVID-19 and against all severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infections (symptomatic or asymptomatic) was estimated. VE was estimated using a Cox regression model, with vaccination status as a time-varying variable. Findings:In total, 1504 HCWs were enrolled in this study; 70% had evidence of prior SARS-CoV-2 infection. VE was 65.1% [95% confidence interval (CI) 37.7-80.5] against COVID-19, 58.2% (95% CI 15.7-79.3) among participants without prior SARS-CoV-2 infection, and 73.6% (95% CI 24.3-90.8) among participants with prior SARS-CoV-2 infection. For BNT162b2 alone, VE was 69.5% (95% CI 44.5-83.2). During the period when the Delta variant was predominant, VE was 67.1% (95% CI 38.3-82.5). VE against SARS-CoV-2 infection for the full study period was 36.9% (95% CI 15.8-52.7). Interpretation:This study found moderate primary series VE against COVID-19 among healthcare workers in Albania. These results support the continued promotion of COVID-19 vaccination in Albania, and highlight the benefits of vaccination in populations with high levels of prior infection.

Abstract Background Healthcare workers (HCWs) have experienced high rates of coronavirus disease 2019 (COVID-19) morbidity and mortality. We estimated COVID-19 2-dose primary series and monovalent booster vaccine effectiveness (VE) against symptomatic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron (BA.1 and BA.2) infection among HCWs in 3 Albanian hospitals during January–May 2022. Methods Study participants completed weekly symptom questionnaires, underwent polymerase chain reaction (PCR) testing when symptomatic, and provided quarterly blood samples for serology. We estimated VE using Cox regression models (1 – hazard ratio), with vaccination status as the time-varying exposure and unvaccinated HCWs as the reference group, adjusting for potential confounders: age, sex, prior SARS-CoV-2 infection (detected by PCR, rapid antigen test, or serology), and household size. Results At the start of the analysis period, 76% of 1462 HCWs had received a primary series, 10% had received a booster dose, and 9% were unvaccinated; 1307 (89%) HCWs had evidence of prior infection. Overall, 86% of primary series and 98% of booster doses received were BNT162b2. The median time interval from the second dose and the booster dose to the start of the analysis period was 289 (interquartile range [IQR], 210–292) days and 30 (IQR, 22–46) days, respectively. VE against symptomatic PCR-confirmed infection was 34% (95% confidence interval [CI], −36% to 68%) for the primary series and 88% (95% CI, 39%–98%) for the booster. Conclusions Among Albanian HCWs, most of whom had been previously infected, COVID-19 booster dose offered improved VE during a period of Omicron BA.1 and BA.2 circulation. Our findings support promoting booster dose uptake among Albanian HCWs, which, as of January 2023, was only 20%. Clinical Trials Registration. NCT04811391.

Background Healthcare workers (HCWs) have suffered considerable morbidity and mortality during the COVID-19 pandemic. Few studies have evaluated 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 to December 1, 2021, to evaluate primary series (two-dose) CoronaVac VE against symptomatic SARS-CoV-2 infection. Participants completed weekly symptom questionnaires, provided nasal swabs for SARS-CoV-2 RT-PCR testing when symptomatic, and provided serology samples at enrolment 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 covariate. Results We enrolled 1582 HCWs. At enrolment, 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 variant. The adjusted primary series VE against COVID-19 illness was 29% (95% CI:-51%;67%). For the delta-predominant period, adjusted primary series VE was 19% (95% CI:-81%;64%). For the entire analysis period, adjusted primary series VE was 39% (95% CI:-40%;73%) for HCW vaccinated within 14–149 days, and 19% (95%CI:-81;63) for those vaccinated ≥150 days. Conclusions During a delta-predominant period in Azerbaijan, point estimates suggest that primary series CoronaVac protected nearly 1 in 3 HCWs against COVID-19, but this finding was not statistically significant. Our findings underscore the need to consider booster doses in individuals who have received primary series CoronaVac.

Prospective home injuries (HIs) and detailed exposure information are generally scarce to study risk factors. We assessed the associations between physical household environment, behaviours and Do-It-Yourself (DIY), gardening and domestic activities and HI’s risk in a prospective cohort study. The MAVIE observatory is an e-cohort conducted among volunteers of the French general population. Poisson mixed models were fitted and Risk Ratios estimated to assess the determinant of the number of HIs prospectively recorded during the follow-up. A total of 6146 dwelling adults aged 15 or more were followed up for 4.0 years on average and 12% reported at least one HI during follow-up. Adjusting on socio-demographics variables and self-perception of physical and mental health, no characteristic of the physical environment measured at baseline were associated with HI risk. Storing household products out of their original packaging, DIY activities and using a stool to reach high places were significantly associated with HI with attributable fractions of 12.1%, 6.4% and 6.9% respectively.

BackgroundHome injury (HI) is a significant cause of mortality and morbidity in adults of all ages. Health conditions significantly impact HI among old adults, but little is known for other adults.Study designProspective cohort study.ObjectiveWe assessed the associations between health-related factors and HI’s risk in a French study, the MAVIE (Mutualistes pour la recherche contre les Accidents de la VIE courante) cohort.MethodsPoisson mixed models were fitted using health-related data information (diseases, treatments and disabilities) at baseline and the number of injuries prospectively recorded during the follow-up, adjusting for significant sociodemographics and exposure to a range of home activities. Attributable fractions were estimated based on risk ratio (RR) estimations measured in the fully adjusted models.ResultsA total of 6146 dwelling adults aged 15 or older were followed up for 5.1 years on average. Vertigo or dizziness (RR=2.36, 95% CI 1.06 to 5.01) and sciatica or back pain (RR=1.49, 95% CI 1.08 to 2.05) were independently associated with an increased risk of HI. These two groups of conditions showed the most significant associations among people aged 15–49, whereas musculoskeletal diseases other than rachialgias and arthropathies were the most significant health-related risk factor in people aged 50 and older. Sciatica or back pain represented the highest burden of HIs in overall adults (8%) and among people aged 15–49 (12%).ConclusionOur results suggest that adults with musculoskeletal disorders and vertigo or dizziness symptoms have a higher risk of HI, regardless of age.

MAVIE is a web-based prospective cohort study of Home, Leisure, and Sports Injuries with a longitudinal follow-up of French general population volunteers. MAVIE participants are voluntary members of French households, including overseas territories. Participation in the cohort involves answering individual and household questionnaires and relevant exposures and prospectively reporting injury events during the follow-up. Recruitment and data collection have been in progress since 2014. The number of participants as of the end of the year 2019 was 12,419 from 9,483 households. A total of 8,640 participants provided data during follow-up. Respondents to follow-up were composed of 763 children aged 0-14, 655 teenagers and young adults aged 15-29, 6,845 adults, and 377 people aged 75 or more. At the end of the year 2019, 1,698 participants had reported 2,483 injury events. Children, people aged 50 and more, people with poor self-perceived physical and mental health, people who engage in sports activities, and people with a history of injury during the year before recruitment were more likely to report new injuries. An interactive mobile/web application (MAVIE-Lab) was developed to help volunteers decide on personalized measures to prevent their risks of HLIs. The available data provides an opportunity to analyse multiple exposures at both the individual and household levels that may be associated with an increased risk of trauma. The ongoing analysis includes HLI incidence estimates, the determination of health-related risk factors, a specific study on the risk of home injury, another on sports injuries, and an analysis of the role of cognitive skills and mind wandering. Volunteers form a community that constitutes a population laboratory for preventative initiatives.

Computational advances in smart-phone technology and the development of expert systems has been an opportunity to devise the MAVIE-Lab an innovative Mobile Health Application (mHealth) for primary prevention of Home, Leisure and Sport Injuries (HLIs). Here, we present MAVIE-Lab Sports, the first module of the application focused on sports injuries. MAVIE-Lab was developed in the framework of the MAVIE project. A large web-based cohort launched with the objective of prospectively collecting data related to HLIs. A sample size of 26 000 volunteers have been already enrolled in this cohort and the ultimate goal is to recruit 1 00 000 participants in France. As a first step, the MAVIE-Lab will be available for MAVIE volunteer’s only. MAVIE-Lab Sports is a decision support system (DSS) aimed to enable the self-management the potential risk of injury and to facilitate the choice of preventive measures. The App first allows participants to compare the overall injury risk between different sports. It then provides an estimation of their personal injury risk. Finally, the user is invited to experiment their potential risk change when opting for a set of proposed behavioral changes, protective devices, equipment or sport practice environments. The MAVIE-Lab algorithms were developed using detailed MAVIE cohort data related to participant’s health, demographics, training practices and the occurrence of injuries, there causes, consequences and severity. The model was constructed to predict the injury risk using probabilistic reasoning and graphical modelling through Bayesian Networks. This approach combines qualitative and quantitative modelling, allowing the combination of MAVIE data evidences and prior expert’s information about risk, protection factors and causal relations between them.

Smart-phones technology and the development of mHealth (Mobile Health) applications offer an opportunity to design intervention tools to influence health behavior changes. The MAVIE-Lab is a mHealth application including a DSS (Desicion Support System) to assist in the personalized evaluation of HLIs (Home, Leisure and Sport Injuries) risk and to promote the adoption of prevention measures. MAVIE-Lab Sports will be the first module of the mobile application. The purpose of this PhD project is to improve a particular module of MAVIE-Lab, devoted to sports (MAVIE-Lab Sports), in different aspects: statistical modeling, design and ergonomics. It also aims to evaluate system usability, acceptability, safety and efficacy. The development structure proposed and executed in this thesis will be replicated for the development of future modules for different types of HLIs. This document develops the argument, objectives and advances in the development of the MAVIE-Lab Sports and the future work.