key: cord-0724514-6ymy9dft
authors: Paris, Christophe; Perrin, Sophie; Hamonic, Stephanie; Bourget, Baptiste; Roué, Clémence; Brassard, Olivier; Tadié, Emilie; Gicquel, Vincent; Bénézit, François; Thibault, Vincent; Garlantézec, Ronan; Tattevin, Pierre
title: Effectiveness of mRNA-BNT162b2, mRNA-1273, and ChAdOx1 nCoV-19 vaccines against COVID-19 in health care workers: an observational study using surveillance data
date: 2021-07-13
journal: Clin Microbiol Infect
DOI: 10.1016/j.cmi.2021.06.043
sha: c2be4dfb4723f178a96ce520a5550499cba75cab
doc_id: 724514
cord_uid: 6ymy9dft

OBJECTIVES: Health care workers (HCWs), at increased risk of COVID-19, were among the primary targets for vaccine campaigns. We aimed to estimate the effectiveness of the 3 first COVID-19 vaccines available in Western Europe for their protection. METHODS: We merged two prospective databases that systematically recorded, in our institution: i) HCWs positive for SARS-CoV-2 by RT-PCR on nasopharyngeal sample; ii) HCWs who received at least one dose of COVID-19 vaccine. We excluded HCWs with SARS-CoV-2 infection during the 6 months prior to the study. HCWs were categorized as non-vaccinated if they received no vaccine and until first injection +13 days, partially vaccinated from first injection +14 days to second injection +13 days, and fully vaccinated thereafter. RESULTS: Of the 8,165 HCWs employed in our institution, 360 (4.4%) tested positive for SARS-CoV-2 by RT-PCR during the study period (January 4(th) to May 17(th) 2021): Incidence was 9.1% (8.2-10.0) in non-vaccinated HCWs; 1.2% (0.7-1.9) after one dose of ChAdOx1 nCoV-19; 1.4% (0.6-2.3), and 0.5% (0.1-1.0), after one, and two doses, of mRNA BNT162b2; 0.7% (0.1-1.9), and 0%, after one, and two doses, of mRNA-1273 (P<0.0001). Vaccine effectiveness (Cox Model), was estimated at, respectively, 86.2% (76.5-91.0), 38.2% (6.3-59.2), and 49.2% (19.1-68.1) 14 days after the first dose for ChAdOx1 nCoV-19, mRNA-1273, and mRNA-BNT162b2; 100% (ND), and 94.6% (61.0-99.2) 14 days after the second dose for mRNA-1273, and mRNA-BNT162b2. CONCLUSIONS: In this real-world study, the observed effectiveness of COVID-19 vaccines in HCWs was in line with the efficacy reported in pivotal randomized trials.

Objectives: Health care workers (HCWs), at increased risk of COVID-19, were among the 25 primary targets for vaccine campaigns. We aimed to estimate the effectiveness of the 3 first 26 COVID-19 vaccines available in Western Europe for their protection. 27

Methods: We merged two prospective databases that systematically recorded, in our 28 institution: i) HCWs positive for SARS-CoV-2 by RT-PCR on nasopharyngeal sample; ii) 29

HCWs who received at least one dose of COVID-19 vaccine. We excluded HCWs with 30 SARS-CoV-2 infection during the 6 months prior to the study. HCWs were categorized as 31 non-vaccinated if they received no vaccine and until first injection +13 days, partially 32 vaccinated from first injection +14 days to second injection +13 days, and fully vaccinated 33 thereafter. 34

Results: Of the 8,165 HCWs employed in our institution, 360 (4.4%) tested positive for 35 SARS-CoV-2 by RT-PCR during the study period (January 4 th to May 17 th 2021): Incidence 36 was 9.1% (8.2-10.0) in non-vaccinated HCWs; 1.2% (0.7-1.9) after one dose of ChAdOx1 37 nCoV-19; 1.4% (0.6-2.3), and 0.5% (0.1-1.0), after one, and two doses, of mRNA BNT162b2; 38 0.7% (0.1-1.9), and 0%, after one, and two doses, of mRNA-1273 (P<0.0001 Rennes University Hospital is a 1500-bed hospital which serves as a referral centre for 62

Western France (population catchment area, 1.5 million inhabitants). All HCWs are registered 63 and followed-up by the department of occupational medicine, with two main objectives: i) to 64 protect them from occupational hazards; ii) to protect their patients. Since March 2020, a 65 database has been implemented to collect data on HCWs who test positive for SARS-CoV-2 66 by RT-PCR on nasopharyngeal samples, from any laboratory which performs these tests, 67 through the national system of health insurance. HCWs were tested in case of any symptom 68 suggestive of COVID-19, or for the purpose of contact tracing, when they were identified as 69 close contact of someone with SARS-CoV-2 infection. All HCWs with positive RT-PCR 70 standardized questionnaire. 72

In January 4 th 2021, we opened a COVID-19 vaccine centre in our hospital, to provide 73 free vaccine to HCWs, initially restricted to those aged 50 years and older (January-February), 74 then open to any HCWs willing to be vaccinated, following the national strategy. All vaccines 75 administered to HCWs were recorded in a database. Three COVID-19 vaccines have been 76 used in our hospital during the study period, according to authorizations of French drug 77 agency, and to their availability: mRNA BNT162b2 was available starting from January 4 th , 78

ChAdOx1 nCoV-19 from February 8 th , and mRNA-1273 from February, 23 rd . The second 79 injection was scheduled 3-4 weeks after the first dose for the mRNA vaccines, and 12 weeks 80 after the first dose for ChAdOx1 nCoV-19. Following reports of severe thrombotic events 81 related to the ChAdOx1 nCoV-19 vaccine, its administration was interrupted on March 15 th in 82

France, and restarted on March 20 th , thereafter restricted to people aged 55 years and older. 83

The two databases (i.e., SARS-CoV-2 infected HCWs, and those who received COVID-84 19 vaccines), were merged with the human resources database that includes all HCWs who 85 worked in the institution during the study period, from January 4 th to May 17 th 2021. HCWs 86 who tested positive for SARS-CoV-2 by RT-PCR within the 6 months before the COVID-19 87 vaccine campaign were excluded, as they were not immediately eligible to vaccination, and 88

were at low risk of COVID-19 during the survey. Data collected were anonymized before 89 analysis, and HCWs were informed of the study and its results through our institution website. 90

In accordance with French law, they did not have to provide written consent. 91

HCWs were categorized as non-vaccinated if they received no vaccine, or until the first 92 injection +13 days, partially vaccinated from the first injection +14 days to the second 93 injection +13 days, and fully vaccinated thereafter Our study has limitations. First, as it was monocentric, its findings may not be 149 generalizable to other settings, given the variability of SARS-CoV-2 variants epidemiology. 150

Second, we could only evaluate vaccine effectiveness during the first months, as the study 151 ends 5 months after the COVID-19 vaccine campaign was started. With 35,217 152

persons.months, our study was not powered to evaluate vaccine effectiveness more than 3 153 months after the first dose. Thirdly, our study was based on passive surveillance, so that we 154 probably underestimated asymptomatic SARS-CoV-2 infection. 155

In conclusion, we found that the effectiveness of the 3 first COVID vaccines available 156 All models were adjusted for age, and occupation, missing data = 15

Safety and Efficacy of the BNT162b2 mRNA Covid-19 Vaccine

Safety of the mRNA-1273 SARS-CoV-2 Vaccine

Safety and efficacy of the ChAdOx1 nCoV-19 vaccine (AZD1222) against SARS-CoV-2: an 201 interim analysis of four randomised controlled trials in Brazil, South Africa, and the UK

Interim Estimates of Vaccine Effectiveness of BNT162b2 and mRNA-1273 COVID-19

Vaccines in Preventing SARS-CoV-2 Infection Among Health Care Personnel

Covid-19 Vaccine in a Nationwide Mass Vaccination Setting

dose BNT162b2 vaccine protects against asymptomatic SARS-CoV-2 infection

Effect of vaccination on 215 transmission of COVID-19: an observationnal study in healthcare workers and their 216 households