Top scientists have reacted positively to early results from drug firms Pfizer and BioNTech that suggest their coronavirus vaccine is more than 90 per cent effective.
The findings – yet to be peer-reviewed – appear to exceed expectations, with reports suggesting that experts thought vaccines would be nearer to 60 or 70 per cent effective.
The data comes from Phase-3 clinical trials that are continuing and further results expected are later this month.
Prof David Taylor, professor emeritus of pharmaceutical and public health policy at University College London, described the results as “a big step towards controlling the pandemic”.
He cautioned, however, that the results were preliminary and did not mean that people should abandon social distancing and other measures to prevent spread of the virus.
Should the vaccine be given approval for widespread use, a maximum of about 50m doses would be available this year, with capacity for 1.3bn more to be manufactured in 2021, according to Pfizer and BioNTech, its German pharmaceutical company trial partner.
While reports indicate the vaccine does cause side effects, such as aches and fever, these are not thought to be worse than what is often seen with vaccines.
Professor David Salisbury, an associate fellow at the London think tank Chatham House and former director of immunisation at the UK Department of Health, said “90 per cent is a great result”. He said it remained to be seen how safe the vaccine was and how long the protection it offered lasted.
"Everybody is excited about a vaccine with 90 per cent reported efficacy," he told The National.
Pfizer and BioNTech said there have been 94 Covid-19 cases so far among participants in its Phase-3 clinical trials, in which people are given either the vaccine or a placebo.
The split of cases between those vaccinated and those given the placebo indicated “a vaccine efficacy rate above 90 per cent” seven days after the second dose of the vaccine, which is given 21 days after the first.
The key questions about the Pfizer/BioNTech vaccine candidate had been about the ability to manufacture it at scale and toxicity, according to Prof Ian Jones, a professor of virology at the University of Reading in the UK.
Toxicity was a potential concern because the vaccine consists of messenger RNA (mRNA), a type of genetic material. As yet, no mRNA vaccines have been approved for use in humans.
"The trial data show excellent results in both of those areas, really impressive protection and no reported adverse events," Prof Jones told The National.
“The only things we will not know for some time is the longevity of the response in all age groups, but assuming antibody [levels] are high that should be at least as good as any other vaccine currently in trial.
“More generally this would appear to indicate that this approach has legs and is likely to useful for other emerging diseases.”
The Pfizer and BioNTech vaccine is one of 11 around the world in phase 3 clinical trials, which involve thousands of participants and as well as testing effectiveness, look for rare and potentially harmful side effects.
Other vaccines are expected to report phase 3 data in the coming months, although even before phase 3 trials are completed, some vaccinations programmes have started in China.
Some senior UAE officials and ministers, including Sheikh Mohammed bin Rashid, Vice President and Ruler of Dubai, have already received a coronavirus vaccine developed by the Chinese company Sinopharm.
The Pfizer/BioNTech Phase-3 clinical trials began in late July and have enrolled 43,538 participants, of whom 38,955 had received a second dose of the vaccine as of Sunday.
Overall 42 per cent of participants globally and 30 per cent of those in the US “have racially and ethnically diverse backgrounds”.
“Today is a great day for science and humanity. The first set of results from our phase 3 Covid-19 vaccine trial provides the initial evidence of our vaccine’s ability to prevent Covid-19,” Dr Albert Bourla, Pfizer’s chairman and CEO, said in a statement.
“We are reaching this critical milestone in our vaccine development programme at a time when the world needs it most with infection rates setting new records, hospitals nearing over-capacity and economies struggling to reopen.”
The trial will continue until a total of 164 participants have been confirmed to have had Covid-19. They will also look at how effective the vaccine is at preventing the disease in those who have already had it, and whether the vaccine can prevent severe illness among those infected.
The companies said they hoped to have enough data to apply for an emergency use authorisation for the vaccine from the US Federal Drug Administration in the third week of November.
In total 47 vaccines are in clinical trials, according to the World Health Organisation, with a further 155 in preclinical evaluation, meaning that they have not yet been tested on people.