When could a coronavirus vaccine be available to the public?

Coronavirus vaccine trials are taking place around the world, as governments hope a vaccine to stop the virus will be ready for distribution in the coming months.

There are more than 300 vaccine candidates, according to the World Health Organisation. Around 40 of these are being tested on humans, and nine have reached the “phase 3” trials – the last stage before possible distribution. They have all already signed purchase agreements with global governments.

AstraZeneca is developing one of those nine at Oxford University. The other advanced vaccine candidates come from companies in China, Russia, and the US, including one led by US multinational Johnson & Johnson.

Watch: UK will deliberately infect vaccine volunteers report

A UK Vaccine Taskforce is being led by chief scientific adviser Sir Patrick Vallance and Professor Jonathan Van Tam to accelerate the development of a coronavirus vaccine.

Researchers at the Oxford Vaccine Group began testing the vaccine candidate ChAdOx1 nCoV-19 in humans on April 24 to see whether it can protect healthy people from Covid-19.

Here's what we know so far about the coronavirus vaccine.

Producing a vaccine, which some have predicted could take up to 18 months, is a "colossal undertaking", Business Secretary Alok Sharma has said.

Although nine vaccine candidates are in the final stage of testing, it may be months before they are ready to implement.

The phase 3 vaccine trials will all end when a certain number of people who have received the vaccine and those in the control group have contracted the virus and displayed symptoms.

The study works by randomly allocating volunteers either a ChAdOx1 nCoV-19 vaccine, or a licensed meningitis vaccine, to be used as a control for comparison.

Statisticians will compare the number of infections in the control group, with the number of infections in the vaccinated group.

Therefore, it is necessary for a small number of study participants to develop Covid-19.

How quickly researchers reach the numbers required depends on the levels of virus transmission in the community.

If transmission remains high, enough data may be available in a couple of months but if transmission levels drop, this could take up to six months.

When will a vaccine be available to the public?

Scientists forecast that the first vaccine could have a positive phase 3 trial result by next month at the earliest, or mid-2021 at the latest.

AstraZeneca has already had to pause trials twice after participants fell seriously ill. Although the trials have resumed in the UK, they remain on hold in the US. When the trial restarted in the UK in September,

AstraZeneca said it was on track to submit its vaccine for regulatory approval before 2021. As many as 18,000 people in the UK, US, South Africa and Brazil have received its AZD1222 vaccine in trials so far.

Analysts estimate that a successful vaccine could be approved by a regulator within a month of showing positive phase 3 trial results. However, it would take another six months before the vaccine could be made available for wider public campaigns, as full data would need to be collected and analysed first.

This is 12-18 months after the coronavirus, officially known as Sars-CoV-2, first emerged - however, there are no guarantees.

The vaccine ChAdOx1 nCoV-19 is made from ChAdOx1, a weakened version of a common cold virus (adenovirus) that causes infections in chimpanzees.

It has been genetically changed so it is impossible for it to grow in humans.

Researchers hope their version will make the body recognise and develop an immune response to the spike protein – recognisable in images of the virus – that will help stop Covid-19 from entering human cells and therefore prevent infection.

Watch: Coronavirus - How worried should we be about mutations?

What has the UK government said about a coronavirus vaccine?

The UK has pre-bought six different vaccines - including AstraZeneca’s vaccine, which has been pre-ordered around the world.

Mr Sharma has said he is "proud" of the work taking place at Oxford University.

Patrick Vallance, the UK government’s chief scientific adviser said this week that a few doses of an effective coronavirus vaccine may be available for use before the end of the year.

There is good progress being made,” he said. “Many vaccines now have shown they generate an immune response of a type that ought to be protective, and several vaccines are in very late stage clinical testing, aiming to show that they are both effective and safe.

“We don’t yet know that they will work. But there is increasing evidence that it’s pointed in the right direction.

“It’s possible that some vaccine could be available before the end of the year in small amounts for certain groups, [but] much more likely that we’ll see vaccines becoming available over the first half of next year. Again not certain, but pointed in the right direction, which then of course gives the possibility of a different approach to this virus.”

The Financial Times reported this week that London is to host the world’s first Covid-19 human challenge trials. Healthy volunteers will be deliberately infected with Covid-19 to test the effectiveness of experimental vaccines in UK government-funded trials beginning in January at a secure east London location.

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