In a recent study published on the medRxiv * prepress server, researchers evaluated the effectiveness of the Pfizer – BioNTech BNT162b2 2019 coronavirus vaccine (COVID-19) in seven million adults in the United Kingdom (UK) ) who were eligible to receive booster injections. between September 16 and December 16, 2021.
Study: Efficacy of booster doses of BNT162b2 in England: an observational study in OpenSAFELY-TPP. Image Credit: Jo Panuwat D / Shutterstock
Fund
As part of its national COVID-19 vaccination program, the United Kingdom initially prioritized its high-risk population for booster injections in September 2021 before making it available to its adult population in COVID-19. general. However, after the onset of the coronavirus 2 (SARS-CoV-2) variant of the acute acute respiratory syndrome Omicron, the availability of booster was reduced to three months on December 8. 2021. Reinforcements were previously available six months after an individual received their second dose of COVID-19 vaccine.
About the study
In the present study, the researchers estimated the effectiveness of BNT162b2 vaccine booster injections in adults who had received two doses of vaccine between September 16 and December 16, 2021. The team used data from the OpenSAFELY-TPP database for study analysis. The database contained information on 40% of English primary care practices linked to national coronavirus surveillance data, hospitals and death records. The follow-up of the study continued for 10 weeks or on December 31, 2021, where the researchers compared each booster receptor with a paired non-potentiated control subject based on booster priority and previous vaccination status. .
The team assigned a matching control to each study participant based on the National Health Service (NHS) region, the date of study entry, the vaccine brand, and the date of the second. dose of vaccine. A Cox regression model adjusted for these factors to estimate hazard ratios (HR), where 1-HR expressed as a percentage indicated the effectiveness of BNT162b2 reinforcement. Human resource estimates were compared with those surveyed, in general and separately, during days 1 to 28 and from 29 to 70. In addition, the team estimated HR from days one to seven, from eight to 14, 15 to 28, 29 to 42, and 43 to 70. The study had several results: a positive test for SARS-CoV-2, COVID-19-related death, hospitalization for COVID-19, and no related to COVID-19.
Study results
The study population consisted of 6,990,219 individuals paired as controls and then re-paired in the reinforcement group. As expected, the matching factors and the proportion of people with pre-existing morbidities were similar across study groups. Although the standardized mean difference between the two groups was consistently less than 0.1, subjects in the control group had more learning difficulties, lower frequency of SARS-CoV-2 testing, and higher rates of severe mental illness and deprivation. Detection of 23,151,145 person-weeks of follow-up gave 123,378 positive tests for SARS-CoV-2, 3,672 hospitalizations for COVID-19, 588 deaths for COVID-19, and 6,990 deaths for non-COVID-19.
Potentiated individuals showed an aberrant increase in the aggregate incidence of positive SARS-CoV-2 testing approximately seven days after receiving booster injections; however, they did not show a similar pattern for other severe COVID-19 outcomes. In addition, differences in the aggregate incidence of positive SARS-CoV-2 testing between study groups were evident during the early days.
Consequently, the risk of 10 weeks of positive SARS-CoV-2 testing in the enhanced versus non-potentiated group was 47.3 and 84.0 per 1,000, respectively, corresponding to a risk difference of 36.8 per 1,000. . The difference in risk for hospitalization for COVID-19, deaths for COVID-19, and deaths for non-COVID-19 were 3.6, 1, and 8.1, respectively.
The (general) reinforcement effectiveness during days 1 to 7 was 50.7%, 80.1%, 88.5%, and 80.3% for the positive SARS-CoV-2 test, hospitalization for COVID-19, died by COVID-19 and died not by COVID-19. . In addition, the effectiveness of reinforcement against all COVID-19 results was generally lower during days 1 to 28 than between days 29 and 70. In shorter periods, the effectiveness of reinforcement against positive tests of COVID-19 was generally lower. SARS-CoV-2 appeared to decrease by about six weeks after reinforcement. vaccination, 68.2% compared to 45.3% between days 15 to 28 and days 43 to 70.
Conclusions
Overall, a booster injection of BNT162b2 reduced positive SARS-CoV-2 test rates by ~ 50% for the first 10 weeks after booster administration. In addition, booster injections reduced hospitalization rates for COVID-19, deaths for COVID-19, and deaths not for COVID-19. More importantly, the efficacy of the booster remained similar against all serious outcomes of COVID-19, regardless of the vaccine brand used for primary vaccination and previous infection.
In contrast, the estimated effectiveness of reinforcement was lower in those under 65 and in clinically vulnerable populations. Since the current study showed evidence of decreased booster efficacy against positive SARS-CoV-2 testing, the authors emphasized the need to monitor the efficacy of the booster vaccine over time.
* Important news
medRxiv publishes preliminary scientific reports that are not peer-reviewed and therefore should not be considered conclusive, guided by clinical practice or health-related behavior, or treated as established information.
Source:
- Effectiveness of BNT162b2 Booster Doses in England: An Observational Study in OpenSAFELY-TPP, William J Hulme, Elizabeth J Williamson, Elsie Horne, Amelia CA Green, Linda Nab, Ruth Keogh, Edward PK Parker, Venexia M Walker, Tom M Palmer, Helen J Curtis, Milan Wiedemann, Christine Cunningham, Alex J Walker, Louis Fisher, Brian MacKenna, Christopher T Rentsch, Anna Schultze, Krishnan Bhaskaran, John Tazare, Laurie A Tomlinson, Helen I McDonald, Caroline E Morton, Richard Croker, Colm D Andrews, Lisa EM Hopcroft, Robin Y Park, Jon Massey, Amir Mehrkar, Jessica Morley, Sebastian CJ Bacon, David Evans, Peter Inglesby, George Hickman, Simon Davy, Iaim Dillingham, Tom Ward, Viyaasan Mahalingasivam, Bang Zheng, Ian J Douglas, Stephen JW Evans, Christopher Bates, Jonathan AC Sterne, Miguel A Hernan, Ben Goldacre, medRxiv preprint 2022, DOI: https://doi.org/10.1101/2022.06.06.22276026,