The sample size will have to be expanded across demography to check safety and efficacy
The results of the Phase-1 trials of a novel coronavirus disease (COVID-19) vaccine being made by Oxford University were ‘encouraging’, a recent study has said.
The vaccine, tentatively named ‘ChAdOx1 nCoV-19’ and developed by researchers at Jenner Institute, Oxford University, had succeeded in generating an immune response against the novel coronavirus disease during its Phase-1 trial conducted between April 23 and May 21, 2020, the paper said.
The paper was published in the medical journal The Lancet on July 20, 2020.
ChAdOx1 nCoV-19 is made from a virus (ChAdOx1), that is a weakened version of a common cold virus (adenovirus) which causes infections in chimpanzees. The virus has been genetically changed so that it is impossible for it to replicate in humans.
An agreement was signed between the Oxford University and pharmaceuticals maker AstraZeneca PLC on April 30, 2020, for the trial of the COVID-19 vaccine.
SARS-CoV-2, the virus that causes COVID-19, has spread globally and was declared a pandemic on March 11, 2020 by the World Health Organization (WHO). More than 14 million people globally have been infected as of July 19, 2020, with more than 597,000 deaths.
ChAdOx1 nCoV-19 vaccine, when given as a single dose, was safe and tolerated, the paper said. No serious adverse reactions to ChAdOx1 nCoV-19 occurred, the paper claimed.
The paper was authored by Pedro M Folegatti, Katie J Ewer and others on behalf of researchers of the Oxford COVID Vaccine Trial Group led by Andrew Pollard.
One among 137 vaccines
No vaccines have been approved for prevention of COVID-19 till now. There are currently more than 137 candidates undergoing preclinical development and 23 in early clinical development, according to WHO.
The UK vaccine has been tested on volunteers aged 18-55 years and has stimulated the body to produce both antibodies and ‘killer T-cells’, the paper said.
T-cell responses play an important role in COVID-19 mitigation, the paper noted, citing several studies. Hence, this ‘vaccine trial’ was very significant because while antibodies were likely to become ineffective within months, T-cells might stay in circulation for years.
Trial mostly on white males and females
The findings of the study could not be easily generalised, since this was a first-in-human study of fairly young and healthy volunteers, the majority of whom were white, the paper said.
Of the total participants, 49.8 per cent participants were female and 50.2 per cent were male.
Another limitation of the study was the short follow-up reported to date. Hence, the participants will be followed up for at least one year and further results on the safety and effectiveness of the vaccine will be reported when data is available, the paper said.
Volunteers from older age groups with comorbidities, health-care workers and those with higher risk for SARS-CoV-2 exposure are being recruited and assessed for efficacy and safety of the vaccine, the paper said.
‘ChAdOx1 nCoV-19’ will be given as a single-dose or in two-doses in further trials to be conducted in the UK and overseas.
The research team will also evaluate the vaccine in children, once sufficient safety data have been accumulated in adult studies. The next study will enroll up to 10,260 adults and children and will involve a number of partner institutions across the UK, the Oxford University had stated in May.
Phase-3 trials are now underway in Brazil, South Africa and the UK and will evaluate vaccine efficacy in diverse populations.