AstraZeneca, on Monday, announced the interim results of the US trials of the COVID-19 vaccine. The said trial was conducted among 32,000 candidates across the US, Chile, and Peru. The positive results came as a sigh of relief for the people as well as the health workers.
AstraZeneca in collaboration with The University of Oxford has developed its vaccine against COVID-19 – AZD1222. It is considered to be a potential lifesaver in regards that it is cheaper and easy to transport. In India, it is manufactured by Serum Institute of India under the name “Covishield”.
What do the numbers mean?
In a press release on Monday the company had announced that the vaccine reduced symptomatic COVID-19 by 79%, reduced severe cases, and hospitalization by 100%. It also said that it had 80% efficacy, among people over 65.
It meant that the possibility of developing COVID-19 symptoms reduced by 79% on being vaccinated. This also meant that vaccination reduced the chances of the symptoms becoming lethal and reduced the chances of hospitalization.
ANN FALSEY, A PROFESSOR OF MEDICINE AT THE UNIVERSITY OF ROCHESTER SCHOOL OF MEDICINE STATED IN THE COMPANY’S NEWS RELEASE:
“It’s exciting to see similar efficacy results in people over 65 for the first time. This analysis validates the AstraZeneca COVID-19 vaccine as a much-needed additional vaccination option, offering confidence that adults of all ages can benefit from protection against the virus.”
Why the variance in results?
The vaccine efficacy in the UK and Brazil trials, conducted in the month of November 2020, was found to be 62% when the two doses were given four weeks apart. It was found much lower- 54.9% – in the UK, Brazil, and South Africa Trials when the two doses were given six weeks apart. The US trials showed much more encouraging results than the UK trials.
“The absolute efficacy is higher in this new study than observed in the Oxford-led studies, as efficacy is affected by the protocol case definition (higher for more severe cases) and the population in which the study is conducted. Today’s findings are in line with findings from other major vaccine developers who studied efficacy in the US,” The University of Oxford stated in the press release.
The results are also affected by the population involved. The US trial included: 79% Caucasian, 22% Hispanic, 8% African American, 4% Native American, and 4% Asian. About 20% of participants were over 65 years and 60% had other health problems.