To what extent AstraZeneca ChAdOx1 nCoV-19 vaccine is safe and effective? Rapid systematic review

Abstract

Until now, there are more than two hundred million confirmed cases of COVID-19 including more than seven million deaths. Clinical trials of all three vaccines authorized for use in the UK (Pfizer–BioNTech, Oxford–AstraZeneca, and Moderna) have reported high vaccine efficacy. This rapid systematic review was initiated because no systematic review had been conducted to determine the safety and efficacy of AstraZeneca ChAdOx1 nCoV-19 vaccine. Evidence acquisition: A systematic search in the following platforms: PubMed, Google Scholar, Scopus, WOS, and MEDLINE databases for all articles in the English language regarding safety and efficacy of SARS-CoV-2 vaccine ChAdOx1 nCoV-19 was performed. Papers published up to end of June were included. Evidence synthesis: Out of 477 retrieved articles, fifteen are included. All the selected articles are concerned with evaluation of AstraZeneca ChAdOx1 nCoV-19 vaccine. Three of them discussed the effectiveness of ChAdOx1 nCoV-19 vaccine, while thirteen (one is common with the group of the effectiveness) measured the adverse effects associated with the vaccine. Because thrombosis was recorded as a serious adverse effect developed after ChAdOx1 nCoV-19 vaccination, it was emphasized in a special group to be analyzed separately. In conclusion: the main message of selected papers was that the value of ChAdOx1 nCoV-19 vaccination to provide critical protection should be considered higher compared to the significant worldwide burden of the emerging COVID-19 infection. No causal relations were found to link cases- having thrombotic adverse reactions to the vaccine.

Vaccination and COVID-19 infection among adults aged 45 years and above in a North-Eastern state of India

“…Epidemiological studies on vaccine effectiveness had been carried out in various countries as it is necessary to complement the results of pre-licensing trials to estimate the efficacy of these vaccines at the population level in real-world conditions and had offered best practice guidance on how to undertake post-introduction evaluations of the effectiveness of COVID-19 vaccines. [ 7 8 ] Observational studies conducted in different countries indicated the high effectiveness of the vaccine in preventing severe outcomes. [ 9 10 ]…”

“…[ 20 ] Another vaccine study from Chile found that, among persons who were fully immunized with CoronaVac, the adjusted vaccine effectiveness was 65.9% (95% confidence interval [CI], 65.2 to 66.6) for the prevention of COVID-19 and 87.5% (95% CI, 86.7 to 88.2) for the prevention of hospitalization, 90.3% (95% CI, 89.1 to 91.4) for the prevention of intensive care unit (ICU) admission, and 86.3% (95% CI, 84.5 to 87.9) for the prevention of COVID-19-related death. [ 8 ]…”