Scientists hope to discover whether a potential coronavirus vaccine has worked by the end of August, a pharmaceutical giant has said, as it begins production ahead of the results being announced.

Pascal Soriot, chief executive of AstraZeneca, said the company had already started to manufacture the Oxford University Covid-19 vaccine to ensure, if it does pass human trials, it can be made available in the autumn.

It comes as trials of the potential vaccine have started in Brazil, a new epicentre of the pandemic, to ensure the study can be properly tested as transmission rates fall in the UK.

Mr Soriot told BBC Radio 4’s Today programme: “We are starting to manufacture this vaccine right now.

“And we have to have it ready to be used by the time we have the results.

“And of course, with this decision comes a risk but it is a financial risk and that financial risk is that if the vaccine doesn’t work, and we will find this out at the end of August, then all the materials, all the vaccines we have manufactured will be wasted.”

He said AstraZeneca would make no profit from the supply of the vaccine, adding: “We felt that there are times in life that corporations need to step up and contribute to resolving a big problem like this one, so decided to do it at no profit.”

On Thursday, AstraZeneca signed a deal with the Coalition for Epidemic Preparedness Innovations (Cepi) to help manufacture 300 million globally accessible doses of the coronavirus vaccine candidate being developed by the Jenner Institute at the University of Oxford.

Last month, Mr Soriot said AstraZeneca received an order from the British Government to supply 100 million doses of the vaccine, and that the company will start delivering these in September subject to successful human trials.

The Jenner Institute and the Oxford Vaccine Group began development on a vaccine in January, using a virus taken from chimpanzees.

An initial phase of testing began on 160 healthy volunteers between 18 and 55, with the study now set to progress to phases two and three, which involve increasing the testing to up to 10,260 people and expanding the age range of volunteers to include children and the elderly.

But Professor Adrian Hill, director of the Jenner Institute, said there were concerns that the low transmission rate of the virus in the community could leave the trial with only a 50% chance of success.

Meanwhile, UK-based vaccine manufacturer Seqirus announced it is working in partnership with parent company CSL, CEPI and the University of Queensland to help develop a candidate Covid-19 vaccine in Australia.

Its manufacturing base in Liverpool is producing an adjuvant, an agent which improves the immune response of a vaccine.