The UK is making plans to roll out a coronavirus vaccine as soon as one is approved.
Earlier this week Pfizer and BioNtech announced a major breakthrough in the race for a Covid-19 vaccine, with early results suggesting their jab is 90% effective.
But experts say more than one vaccine will be needed to combat the pandemic, and researchers across the world are working to develop jabs that protect against the virus.
– What progress is being made with Covid-19 vaccines?
There are more than 200 candidates being tested around the world.
About 12 are in in the final stages of testing, but the one from German firm BioNTech and US pharmaceutical company Pfizer is the first to report any results.
There are two frontrunners in the vaccine race – the one from Pfizer, called BNT162b2, and another being developed by the University of Oxford and AstraZeneca, which is also in phase three clinical trials.
It is thought results of the Oxford-AstraZeneca trials will be released before Christmas.
Other potential vaccines in phase three trials have been developed by US drugs firm Moderna and biotech company Novavax.
And on Wednesday Russia announced that early data for its Sputnik V vaccine suggest it is 92% effective.
– How promising are the results from the Pfizer/BioNTech vaccine?
They findings are interim, and studies are to continue, but analysis shows the vaccine can prevent more than 90% of people from getting Covid-19.
It has been tested on 43,500 people in six countries and no safety concerns have been raised.
The analysis was carried out after 94 confirmed cases of Covid-19 were found among those taking part in the trial.
The jab is known as a messenger RNA (mRNA) vaccine, which uses the virus’s genetic code rather than any part of the virus itself, and is injected into the body where it enters cells and tells them to create antigens.
– When can we expect results from the Oxford vaccine?
More than 20,000 volunteers are participating in trials for the Oxford vaccine, in countries including the UK, South Africa, Brazil and Kenya.
Professor Andrew Pollard, the head of Oxford’s vaccine trial team, said he is optimistic that data on its safety and efficacy will be available by the end of the year.
The Oxford vaccine, called ChAdOx1 nCoV-19, uses a weakened version of a common cold virus (adenovirus) which causes infections in chimpanzees.
– What other trials are ongoing in the UK?
Another jab is being developed by Imperial College London.
It is in phase one of clinical testing, where doses are given to a small group of people to determine whether it is safe and to learn more about the immune response.
Professor Robin Shattock, who is leading Imperial’s vaccine effort, said data on its efficacy will be available in the middle of next year.
Pharmaceutical companies Sanofi and GlaxoSmithKline have also teamed up with the hope of making a vaccine available by the middle of next year.
The Sanofi/GSK candidate is in the phase two stage, where the vaccine is given to hundreds of people so scientists can learn more about its safety and correct dosage, and phase three is planned by the end of the year.
– What potential vaccines does the UK have access to?
The UK has secured 40 million doses of the Pfizer/BioNTech vaccine, the first agreement the firms signed with any government.
Downing Street has said the UK will have procured 10 million doses to be distributed by the end of this year.
In August, the Government announced the UK has secured access to six Covid-19 vaccine candidates in development, representing 340 million doses.
The deals cover four types of vaccine – adenoviral, mRNA, inactivated whole virus, and protein adjuvant.
Adenoviral vaccines are weakened versions of adenoviruses, while mRNA candidates use the virus’s genetic code, as with the Pfizer/BioNTech jab.
Inactivated whole virus vaccines contain whole bacteria or viruses which have been killed, while protein adjuvant jabs are those where an adjuvant is added to enhance the immune response.
– When could a vaccine become available in the UK?
A vaccine usually takes years, often decades, to develop, but scientists working on potential coronavirus jabs are hoping to achieve the same amount of work in a few months.
Pfizer and BioNTech plan to apply to the US Food and Drug Administration by the end of this month for emergency approval to use the vaccine.
It is hoped that the first phase of the vaccination programme in the UK will protect 99% of those at risk of death from Covid-19, before moving on to younger age groups.
The military and NHS staff are on standby to roll out a vaccine across the UK from the start of December, Health Secretary Matt Hancock has said, with GPs, new vaccination centres and pharmacists all playing a role.