COVID-19 vaccine effectiveness among healthcare workers in Albania (COVE-AL): protocol for a prospective cohort study and cohort baseline data

Abstract

IntroductionCritical questions remain about COVID-19 vaccine effectiveness (VE) in real-world settings, particularly in middle-income countries. We describe a study protocol to evaluate COVID-19 VE in preventing laboratory-confirmed SARS-CoV-2 infection in health workers (HWs) in Albania, an upper-middle-income country.Methods and analysisIn this 12-month prospective cohort study, we enrolled HWs at three hospitals in Albania. HWs are vaccinated through the routine COVID-19 vaccine campaign. Participants completed a baseline survey about demographics, clinical comorbidities, and infection risk behaviours. Baseline serology samples were also collected and tested against the SARS-CoV-2 spike protein, and respiratory swabs were collected and tested for SARS-CoV-2 by RT-PCR. Participants complete weekly symptom questionnaires and symptomatic participants have a respiratory swab collected, which is tested for SARS-CoV-2. At 3, 6, 9 months and 12 months of the study, serology will be collected and tested for antibodies against the SARS-CoV-2 nucleocapsid protein and spike protein. VE will be estimated using a piecewise proportional hazards model (VE=1−HR).Baseline dataFrom February to May 2021, 1504 HWs were enrolled. The median age was 44 (range: 22–71) and 78% were female. At enrolment, 72% of participants were seropositive for SARS-CoV-2. 56% of participants were vaccinated with one dose, of whom 98% received their first shot within 4 days of enrolment. All HWs received the Pfizer BNT162b2 mRNA COVID-19 vaccine.Ethics and disseminationThe study protocol and procedures were reviewed and approved by the WHO Ethical Review Board, reference number CERC.0097A, and the Albanian Institute of Public Health Ethical Review Board, reference number 156. All participants have provided written informed consent to participate in this study. The primary results of this study will be published in a peer-reviewed journal at the time of completion.Trial registration numberNCT04811391.

Factors associated with receipt of COVID-19 vaccination and SARS-CoV-2 seropositivity among healthcare workers in Albania (February 2021–June 2022): secondary analysis of a prospective cohort study

“…In addition, study staff approached HCWs at various busy points in each of the hospitals. 17 At enrollment, participants completed a survey, which included questions on demographics, personal health information, date of prior confirmed SARS-CoV-2 infection (RT-PCR, antigen rapid diagnostic test, or serology), occupation, performance of aerosol generating procedures (APGs), influenza vaccination during the 2020/2021 season, and COVID-19 vaccine history. During the study, a weekly questionnaire was administered to all participants to reassess COVID-19 vaccination status, including date of vaccine receipt.…”

“…During the study, a weekly questionnaire was administered to all participants to reassess COVID-19 vaccination status, including date of vaccine receipt. 17 Vaccination status was verified using the national integrated immunization electronic system (IIS) and the family care physician's web-based system (E-vizita) in order to ensure completeness and validity of the vaccination data. In case of any discrepancies between the self-reported vaccination and IIS or E-vizita, such as the date of vaccination, we relied on the data from the national databases.…”

“…We used data from a prospective cohort study of COVID-19 vaccine effectiveness among HCWs in Albania 17 to evaluate factors associated with uptake of COVID-19 vaccine primary series and booster dose between February 2021 and June 2022, and factors associated with SARS-CoV-2 infection prior to vaccination.…”

Estimating the seroprevalence of SARS-CoV-2 antibodies: Understanding population-level immunity in Albania at the end of the Alpha variant wave

“…ly [4]. A recent study conducted among health care workers in Albania between February and May 2021 has found a seroprevalence of 72% [5].…”

“…These data contrast with prior seroprevalence information we have reported from one year earlier in June-July 2020, and in December 2020, before the Alpha variant surge in Albania; we found using the same methodology seroprevalence rates of 7.5% and 48.2%, respectively [ 4 ]. A recent study conducted among health care workers in Albania between February and May 2021 has found a seroprevalence of 72% [ 5 ].…”