tetano
Editor, Senior Moderator
Open Forum Infect Dis
. 2023 Oct 12;10(10)
fad479.
doi: 10.1093/ofid/ofad479. eCollection 2023 Oct. Primary Series and Booster Coronavirus Disease 2019 Vaccine Effectiveness in a Cohort of Healthcare Workers in Albania During a BA.1 and BA.2 Variant Period, January-May 2022
Iris Finci[SUP] 1 [/SUP], Madelyn Yiseth Rojas Castro[SUP] 2 [/SUP], Iris Hasibra[SUP] 3 [/SUP], Jonilda Sulo[SUP] 4 5 [/SUP], Albana Fico[SUP] 3 6 [/SUP], Rovena Daja[SUP] 3 [/SUP], Adela Vasili[SUP] 3 [/SUP], Majlinda Kota[SUP] 3 [/SUP], Iria Preza[SUP] 7 [/SUP], Barbara Mühlemann[SUP] 8 9 [/SUP], Christian Drosten[SUP] 8 9 [/SUP], Richard Pebody[SUP] 1 [/SUP], Kathryn E Lafond[SUP] 10 [/SUP], Esther Kissling[SUP] 2 [/SUP], Mark A Katz[SUP] 1 [/SUP], Silvia Bino[SUP] 3 4 [/SUP]
Affiliations
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.
Keywords: COVID-19; Omicron; booster dose; healthcare workers; vaccine effectiveness.
. 2023 Oct 12;10(10)
fad479.doi: 10.1093/ofid/ofad479. eCollection 2023 Oct. Primary Series and Booster Coronavirus Disease 2019 Vaccine Effectiveness in a Cohort of Healthcare Workers in Albania During a BA.1 and BA.2 Variant Period, January-May 2022
Iris Finci[SUP] 1 [/SUP], Madelyn Yiseth Rojas Castro[SUP] 2 [/SUP], Iris Hasibra[SUP] 3 [/SUP], Jonilda Sulo[SUP] 4 5 [/SUP], Albana Fico[SUP] 3 6 [/SUP], Rovena Daja[SUP] 3 [/SUP], Adela Vasili[SUP] 3 [/SUP], Majlinda Kota[SUP] 3 [/SUP], Iria Preza[SUP] 7 [/SUP], Barbara Mühlemann[SUP] 8 9 [/SUP], Christian Drosten[SUP] 8 9 [/SUP], Richard Pebody[SUP] 1 [/SUP], Kathryn E Lafond[SUP] 10 [/SUP], Esther Kissling[SUP] 2 [/SUP], Mark A Katz[SUP] 1 [/SUP], Silvia Bino[SUP] 3 4 [/SUP]
Affiliations
- PMID: 37885795
- PMCID: PMC10599317
- DOI: 10.1093/ofid/ofad479
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.
Keywords: COVID-19; Omicron; booster dose; healthcare workers; vaccine effectiveness.