UK's Oxford vaccine phase-2 trial indicates strong results in older adults, says Lancet study

New Delhi [India], November 19 : In a major development, UK's Covid-19 vaccine has shown similar strong immune response in healthy older adults -aged 56 years and above- to those seen in people between 18 to 55 years, according to findings from a phase-2 trial.
The Oxford Covid-19 vaccine has collaborated with Indian drug maker--Serum Institute of India (SII) for which phase 2 clinical trials are being conducted in India also.
The findings of the study have been published in the leading medical journal--Lancet in which authors have noted that their findings could be encouraging if the immune responses found in their study are associated with protection against infection with SARS-CoV-2, but this study did not assess the efficacy, which will be confirmed only after completion of the ongoing Phase-3 trials.
The study is the fifth published clinical trial of a vaccine against SARS-CoV-2 tested in an older adult population (aged 18-55 years, 56-69 years, and those 70 years and older).
"The vaccine was safe and well-tolerated, with reduced reactogenicity in older adults. Antibody responses against the SARS-CoV-2 spike protein were induced in all age groups and were boosted and maintained at 28 days after booster vaccination, including in the 70 years and older group. Cellular immune responses were also induced in all age and dose groups, peaking at day 14 after vaccination," noted the research paper.
The research paper highlighted that the population at the greatest risk of serious Covid-19 includes people with co-existing health conditions and older adults.
"The immune correlates of protection against SARS-CoV-2 have not yet been determined, but neutralising antibodies are thought to be associated with protection, and in a Covid-19 non-human primate challenge model, neutralising antibody responses correlated with protection," it mentions.
"These findings have led to the use of neutralisation assays to assess immune responses in recent human COVID-19 vaccine trials," it said.
"Immunisation with ChAdOx1 nCoV-19 results in the development of neutralising antibodies against SARS-CoV-2 in almost 100 per cent of participants including older adults without severe co-morbidities, with higher levels in boosted compared with non-boosted groups. Further assessment of the efficacy of this vaccine is warranted in all age groups and individuals with co-morbidities," noted the study.
The vaccine is being developed by Oxford Universitywith AstraZeneca Plc.
During this week three vaccines - the Pfizer-BioNTech, as well as Moderna and Sputnik have reported good preliminary data from phase three trials, with the one by Pfizer suggesting that 94 per cent of those above the age of 65 could be protected from Covid-19.