A Brazilian doctor voluntarily received an injection as part of a phase 3 vaccine developed by Oxford University and the British pharmaceutical company AstraZeneca in July 2020.
Nelson Almeida AFP | Getty Images
LONDON – The coronavirus vaccine, developed by the University of Oxford and AstraZeneca, is safe and elicits a similar immune response in all adults, according to preliminary findings from a peer-reviewed phase two study.
Promising early-stage results were published in The Lancet, one of the world̵
A study of 560 healthy adults, including 240 over the age of 70, found the vaccine to be safe and produced a similar immune response in people over the age of 56 and those between the ages of 18 and 55.
Older people face a “significant risk” of developing severe disease when infected with Covid-19, the WHO said, citing reduced immune function and potential underlying health conditions. However, people of all ages are at risk of contracting the virus.
The British pharmaceutical giant AstraZeneca, which works in collaboration with the University of Oxford, said earlier that interim data showed that their experimental vaccine had elicited an immune response in adults and younger people.
Many believe that a safe and effective vaccine is a game-changing battle against the coronavirus pandemic that has claimed the lives of more than 1.3 million people worldwide.
Huge challenges remain before the vaccine is released. The global battle to secure future supplies has raised concerns about fair access, while questions remain about logistics, distribution and costs.
The Oxford vaccine candidate has been found to cause few side effects and cause immune reactions in both parts of the immune system in all age groups and at low and standard doses.
Preliminary results showed that the vaccine – ChAdOx1 nCoV-19 – elicited what is known as a “T-cell response” within 14 days after the first dose, and an antibody response within 28 days after the booster dose. Scientists expect T-cell responses to play a role in long-term immunity to the virus.
Dr Maheshi Ramasamy, co-author of the study at Oxford University, said antibody and T-cell responses in the elderly were “stable” and “encouraging”.
“The populations with the highest risk of serious COVID-19 disease include people with pre-existing health and older adults,” Ramazami said.
“We hope this means that our vaccine will help protect some of the most vulnerable people in society, but more research will be needed before we are sure.”
Limitations of the study
The authors of the Oxford study say their results could be encouraging if immune responses are found to be linked to protection against Covid-19 infection. However, the second phase trial did not evaluate the efficacy of the vaccine and the second phase trials continued to confirm this.
Results are expected later this year, depending on the extent of infection in clinical trial communities.
The authors noted some limitations in their study, including that participants in the oldest age group had a mean age of 73 to 74 years and few underlying health conditions, and almost all participants were white and non-smokers.
It is said that people from different backgrounds, countries and ethnic groups are involved in the three-phase phase.
The study comes days after two other vaccine manufacturers announced encouraging results from phase three studies. They said their experimental vaccines were highly effective in protecting against the coronavirus, raising optimism at a time when health systems in Europe and the United States were once again pushed to the brink.
Pfizer and BioNTech announced on Wednesday that the final analysis found that their vaccine candidate was 95% effective in preventing Covid-19 and seemed to repel severe disease. Earlier this week, Moderna said data from a preliminary phase III trial showed that her vaccine was 94.5% effective.