Session Type: 1-hour Mini Oral Flash
Session Title: 1-hour Mini Oral Flash
Authors(s): G. Noberasco (1), D. Olobardi (1), E. Marcenaro (1), A. Battistini (2), B. Bruzzone (2), L. Sticchi (1, 2), F. Copello (3), P. Durando (1, 3), G. Icardi (1, 2), A. Orsi (1, 2)
Authors Affiliations(s): (1) Department of Health Sciences, University of Genoa, Italy, (2) Hygiene Unit, Ospedale Policlinico San Martino IRCCS, Italy, (3) Occupational Medicine Unit, Ospedale Policlinico San Martino IRCCS, Italy
Background:
In Italy the COVID-19 vaccination campaign started on 27th December 2020. Ospedale Policlinico San Martino IRCCS started the administration of the Pfizer-BioNTech COVID-19 vaccine among its healthcare workers the same day. A surveillance system was activated in order to monitor real-life vaccine effectiveness.
Methods:We conducted a test-negative designed case-control study to estimate vaccine effectiveness (VE) of the Pfizer-BioNTech COVID-19 vaccine among healthcare workers. We considered real time PCR assay for the detection of SARS-CoV-2 in nasopharyngeal swab as valid test. Patients with a positive test for SARS-CoV-2 were classified as cases, while those with a negative test were classified as controls. VE was estimated by comparing positivity proportions between the vaccinated and unvaccinated patients. Patients were considered vaccinated 7 days after receiving the second dose of COVID-19 vaccine, patients were considered unvaccinated in absence of vaccination record or whether the test was collected prior to the 8th day after the completion of the vaccine schedule. Odds ratios (ORs) of having received COVID-19 vaccine for cases and controls were compared, with its 95% confidence intervals (CIs). We calculated VE as 1 minus the ORs multiplied by 100%.
Results:We used data from 5646 nasopharyngeal swabs, which yielded 2883 patients and 238.2 patient-years of data. The mean length of the observational period was 30.2 days while the median was 19 (IQ 15-55) days. The mean age of our cohort was 43.8 years (median 47, IQR 31-55), 45.7 years (median 48, IQR 35-55) for the vaccinated group and 41.4 years (median 44, IQR 27.25-54) for the unvaccinated individuals (Figure 1). From the beginning of the vaccination campaign 125 healthcare workers tested positive for SARS-CoV-2 (mean age 43.4 years, median 46, IQR 30-54), 2 were vaccinated and 123 were unvaccinated. Among 2758 workers who tested negative, 1635 were vaccinated and 1123 not vaccinated. Vaccine effectiveness resulted 98.88% with a 95% confidence interval between 95.47% and 99.72% and a p level of significance of p<0.0001. The raw vaccine effectiveness of administrating only the first dose was 91.45% (95% CI 86.46%-94.61%, p<0.0001).
Conclusions:Our preliminary data confirm that Pfizer-BioNTech COVID-19 vaccine is highly effective at preventing COVID-19 disease.
Keyword(s): COVID-19 vaccine, On-field effectiveness, Healthcare workersCOI Other: No conflict of interest
Session Type: 1-hour Mini Oral Flash
Session Title: 1-hour Mini Oral Flash
Authors(s): G. Noberasco (1), D. Olobardi (1), E. Marcenaro (1), A. Battistini (2), B. Bruzzone (2), L. Sticchi (1, 2), F. Copello (3), P. Durando (1, 3), G. Icardi (1, 2), A. Orsi (1, 2)
Authors Affiliations(s): (1) Department of Health Sciences, University of Genoa, Italy, (2) Hygiene Unit, Ospedale Policlinico San Martino IRCCS, Italy, (3) Occupational Medicine Unit, Ospedale Policlinico San Martino IRCCS, Italy
Background:
In Italy the COVID-19 vaccination campaign started on 27th December 2020. Ospedale Policlinico San Martino IRCCS started the administration of the Pfizer-BioNTech COVID-19 vaccine among its healthcare workers the same day. A surveillance system was activated in order to monitor real-life vaccine effectiveness.
Methods:We conducted a test-negative designed case-control study to estimate vaccine effectiveness (VE) of the Pfizer-BioNTech COVID-19 vaccine among healthcare workers. We considered real time PCR assay for the detection of SARS-CoV-2 in nasopharyngeal swab as valid test. Patients with a positive test for SARS-CoV-2 were classified as cases, while those with a negative test were classified as controls. VE was estimated by comparing positivity proportions between the vaccinated and unvaccinated patients. Patients were considered vaccinated 7 days after receiving the second dose of COVID-19 vaccine, patients were considered unvaccinated in absence of vaccination record or whether the test was collected prior to the 8th day after the completion of the vaccine schedule. Odds ratios (ORs) of having received COVID-19 vaccine for cases and controls were compared, with its 95% confidence intervals (CIs). We calculated VE as 1 minus the ORs multiplied by 100%.
Results:We used data from 5646 nasopharyngeal swabs, which yielded 2883 patients and 238.2 patient-years of data. The mean length of the observational period was 30.2 days while the median was 19 (IQ 15-55) days. The mean age of our cohort was 43.8 years (median 47, IQR 31-55), 45.7 years (median 48, IQR 35-55) for the vaccinated group and 41.4 years (median 44, IQR 27.25-54) for the unvaccinated individuals (Figure 1). From the beginning of the vaccination campaign 125 healthcare workers tested positive for SARS-CoV-2 (mean age 43.4 years, median 46, IQR 30-54), 2 were vaccinated and 123 were unvaccinated. Among 2758 workers who tested negative, 1635 were vaccinated and 1123 not vaccinated. Vaccine effectiveness resulted 98.88% with a 95% confidence interval between 95.47% and 99.72% and a p level of significance of p<0.0001. The raw vaccine effectiveness of administrating only the first dose was 91.45% (95% CI 86.46%-94.61%, p<0.0001).
Conclusions:Our preliminary data confirm that Pfizer-BioNTech COVID-19 vaccine is highly effective at preventing COVID-19 disease.
Keyword(s): COVID-19 vaccine, On-field effectiveness, Healthcare workersCOI Other: No conflict of interest