Oxford vaccine offers hope, Serum to seek clinical trials in India
The first set of results from early-stage clinical trials of the Oxford University Covid-19 vaccine candidate show the vaccine is safe and induces an immune reaction, according to results published in the Lancet, a medical journal, on Monday.
The results from Oxford were followed by Indian vaccine manufacturer Serum Institute announcing it would seek regulatory approvals for clinical trials in India and “soon start manufacturing the vaccine in large volumes”. Serum Institute has a manufacturing arrangement with British pharma giant AstraZeneca to produce a billion doses if the Oxford University vaccine candidate was successful.
“The trials have shown promising results… We will be applying for the licensure trials to the Indian regulator in a week’s time,” Serum Institute of India chief executive Adar Poonawalla said, adding that trials in would begin as soon as the approvals were in place.
The results show that vaccine candidate against Sars-CoV-2, the virus that caused Covid-19, produces strong antibody and T cell responses, has few side effects and there have been no serious adverse events.
“If our vaccine is effective, it is a promising option as these types of vaccine can be manufactured at large scale,” said the co-author of the study, Professor Sarah Gilbert, University of Oxford. “A successful vaccine against Sars-CoV-2 could be used to prevent infection, disease and death in the whole population, with high-risk populations such as hospital workers and older adults prioritised to receive vaccination,” Gilbert added. Following assessments of the participants who took part in phase 1 and 2 clinical trials in the UK, T cell responses targeting the Sars-CoV-2 spike protein were markedly increased, peaking 14 days after vaccination, declining slightly by day 56. The T cell response did not increase with a second dose of the vaccine, which is consistent with other vaccines of this kind.
Antibody responses peaked by day 28 and remained high until the measurement at day 56 in the trial. This response was boosted by a second dose. “The immune system has two ways of finding and attacking pathogens — antibody and T cell responses,” said study lead author Professor Andrew Pollard of Oxford University. “This vaccine is intended to induce both, so it can attack the virus when it’s circulating in the body, as well as attacking infected cells. We hope this means the immune system will remember the virus, so that our vaccine will protect people for an extended period. However, we need more research before we can confirm the vaccine effectively protects against Sars-CoV-2 infection, and for how long any protection lasts.”
Assistant Professor Naor Bar-Zeev at the Johns Hopkins Bloomberg School of Public Health in the US said the results augured well for phase 3 trials, but he warned: “Much remains unknown about the longevity of response and immunogenicity in older adults or other specific groups, such as those with co-morbidities, or ethnic or racial groups more severely affected by Covid-19.”
Of the 1,077 participants in the phase 1 trial, 91% were white and the average age of participants was 35 years. Older age groups, those with other health conditions, and ethnically and geographically diverse populations are being recruited for the ongoing phase 2 and 3 trials in the UK, Brazil and South Africa.
“There is still much work to be done before we can confirm if our vaccine will help manage the Covid-19 pandemic, but these early results hold promise,” said Gilbert. “For example, we still do not know how strong an immune response we need to provoke to effectively protect against Sars-CoV-2 infection.”
