Experts have said it is “excellent news” that Pfizer’s coronavirus vaccine is 94% effective in older patients – who are among the most at-risk from Covid-19.

The jab, which is due to arrive in the UK before the end of the year, is 95% effective overall and has passed its safety checks, the pharmaceutical giant and its partner BioNTech said.

The vaccine has been tested on 43,500 people in six countries and no safety concerns have been raised, although around 2% suffered a headache and fatigue.

The UK has secured 40 million doses of the vaccine, with 10 million due by the end of the year if the jab is approved.

Professor Trudie Lang, director of the Global Health Network, Nuffield Department of Medicine, University of Oxford, said: “Today’s update from Pfizer provides further encouraging news and more detail on the protection against disease that their vaccine is showing from this definitive phase III trial.

“The detail on achieving 94% protection in the elderly participants in the trial is particularly excellent news.

“We will need to wait and learn over time how long the protection lasts, and to see whether this vaccine can also prevent transmission – meanwhile, this vaccine does look likely to have a strong role immediately once it is approved in protecting health workers and the vulnerable from disease.

“Another encouraging detail from this update was that of those cases that were considered severe, 90% of these had been vaccinated with a placebo.

“This ability to mitigate severe disease was a key question and so it is impressive that over 90% efficacy appears to be being maintained across ages and severity of disease. The safety data also looks very reassuring.

To go from identifying a new virus to having several vaccines at the point of applying for regulatory approval is an incredible milestone for science

“This is a remarkable and very reassuring situation that we find ourselves in.

“To go from identifying a new virus to having several vaccines at the point of applying for regulatory approval is an incredible milestone for science.”

Stephen Evans, professor of pharmacoepidemiology at London School of Hygiene and Tropical Medicine, said: “This announcement in a press release is very good news indeed.

“There are now rather more data accrued with, it is said, no serious side effects.”

He added that there is some evidence that in older adults there is also very good efficacy with minimal side effects.

Prof Evans said this was “very good news” for this vaccine, and it also makes it more likely that other vaccines will be reasonably effective in older adults.

He added: “While we await a full paper, the FDA (the US Food and Drug Administration) will have access to much more data and details than in a published paper.

“The head of the Biologics Centre at the FDA, responsible for vaccines, has assured us that no politically appointed people are present for the assessment of any vaccines – they are briefed but do not attend the relevant meetings.

“If the data are also submitted to the European Medicines Agency, then we can expect both agencies to conduct a very careful evaluation and we can rely on their conclusions. Relying on a press release is not enough.”