AstraZeneca announced that its COVID-19 vaccine is safe and effective at preventing COVID-19, with no severe cases and no hospitalizations more than 22 days after the first dose, according to a news release from the company. The findings were part of a primary analysis of the Phase III clinical trials from the United Kingdom, Brazil and South Africa and published as a preprint in The Lancet.
Results demonstrated vaccine efficacy of 76 percent after a first dose, with protection maintained to the second dose. With an inter-dose interval of 12 weeks or more, vaccine efficacy increased to 82 percent.
The analysis also showed the potential for the vaccine to reduce asymptomatic transmission of the virus, based on weekly swabs obtained from volunteers in the United Kingdom trial. The data showed that PCR positive readings were reduced by 67 percent after a single dose, and 50 percent after the two dose regimen, supporting a substantial impact on transmission of the virus.
The primary analysis for efficacy was based on 17,177 participants accruing 332 symptomatic cases from the Phase III UK (COV002), Brazil (COV003) and South Africa (COV005) trials led by Oxford University and AstraZeneca, a further 201 cases than previously reported.
Professor Andrew Pollard, Chief Investigator of the Oxford Vaccine Trial, and co-author of the paper, said: “These new data provide an important verification of the interim data that has helped regulators such as the MHRA in the UK and elsewhere around the world to grant the vaccine emergency use authorisation. It also helps to support the policy recommendation made by the Joint Committee on Vaccination and Immunisation for a 12-week prime-boost interval, as they look for the optimal approach to roll out, and reassures us that people are protected 22 days after a single dose of the vaccine.”
Data will continue to be analyzed and shared with regulators around the world to support their ongoing rolling reviews for emergency supply or conditional approval during the health crisis, the company said. AstraZeneca said itis also seeking emergency use listing from the World Health Organization (WHO) for an accelerated pathway to vaccine availability in low-income countries.
The vaccine can be stored, transported and handled at normal refrigerated conditions (two-eight degrees Celsius/36-46 degrees Fahrenheit) for at least six months and administered within existing healthcare settings.
In addition to the program led by Oxford University, AstraZeneca is conducting a large trial in the United States and globally. In total, Oxford University and AstraZeneca expect to enroll up to 60,000 participants globally.
