Results from the interim analysis have confirmed that the Oxford Covid-19 vaccine has shown a satisfactory safety profile and is effective against symptomatic Coronavirus caused disease, with only three out of 23,745 participants experiencing serious adverse events.
The results from the first full studied efficacy result published for a covid vaccine in Lancet found that the vaccine protects against symptomatic disease in 70 per cent of cases -- with vaccine efficacy of 62 per cent for those given two full doses, and of 90 per cent in those given a half than a full dose.
The results were based on a combined analysis from the phase III trials in the UK and Brazil involving 11,636 people, alongside safety data from a total of 23,745 participants in 4 trials in the UK, Brazil and South Africa.
Volunteers are recovering and have remained in the trial.
Study author and doctor Merryn Voysey from the University of Oxford, “The results presented in this report provide the key findings from our first interim analysis.”
"In future analyses, with more data included as it becomes available, we will investigate differences in key subgroups such as older adults, various ethnicities, doses, timing of booster vaccines, and we will determine which immune responses equate to protection from infection or disease," the author added.
The Oxford Covid-19 vaccine uses a chimpanzee adenovirus viral vector that cannot cause disease in humans and expresses the SARS-CoV-2 spike protein, meaning the vaccine passes the spike protein genetic code into vaccinated people's cells. This then produces the protein and prepares the immune system to identify the virus and attack it.
The past trials results have observed that the vaccine produces antibody and T cell immune responses and is safe for adults.
Study lead author Professor Andrew Pollard said, "Our findings indicate that our vaccine's efficacy exceeds the thresholds set by health authorities and may have a potential public health impact.”
All 23,745 participants were observed to have suffered from a severe health condition and were hospitalized. After the first dose for 21 days duration, there were 10 cases of hospitalisation for Covid-19, all in the control arm, and two were classified as severe, including one death.
"We have shown for the first time that an adenoviral vectored vaccine - a type of vaccine technology which has been in use since 2009 - is efficacious and could contribute to disease control in the Covid-19 pandemic," said Professor Sarah Gilbert from University of Oxford.
Also Read: Covid-19 vaccine update: Covaxin expected to be available for public use by February 2021
The authors noted that they are not yet able to assess the duration of protection, as the first trials were initiated in April 2020 and all disease episodes have accrued within six months of the first dose is administered.
Further evidence will be required to determine the duration of protection and the need for additional booster doses of vaccine, the authors said.
Source: IANS