Here is our updated timeline on the global hunt for coronavirus vaccine:
December 31: New coronavirus identified
China reports a cluster of cases of pneumonia in the city of Wuhan, leading to the identification of a new coronavirus.
January 10: Scientists reveal genome of a new coronavirus
A week and a half after China reports a new form of pneumonia, scientists map the genome sequence of what is later identified as COVID-19, a key first step on the road to finding a vaccine.
January 11: Scientists publish molecular blueprint of the new coronavirus
The coronavirus sequenced genome is published, which marks the start of international efforts to study a vaccine.
March 16: Vaccine trial begins in the US
The US National Institutes of Health begins trial of an "investigational" vaccine on 45 healthy adults, aged 18 to 55, after promising results in animal models.
The trial is funded by the US National Institutes of Health and Massachusetts-based biotechnology company, Moderna Inc, and it is set to last six weeks.
The vaccine is officially named mRNA-1273.
April 2: 'Trials to test tuberculosis vaccine against COVID-19 underway'
France's National Institute of Health and Medical Research says "clinical trials to test the BCG vaccine's efficacy against COVID-19 are underway or about to start in the Netherlands, Germany, France, Spain and Australia."
April 13: EU pledges €80 million for vaccine research
The EU funding is earmarked to support German biopharmaceutical company CureVac in developing a vaccine.
April 14: GSK and Sanofi team up to find COVID-19 vaccine
The British-French duo, GlaxoSmithKline and Sanofi announce clinical trials for the second half of 2020, hoping to make - if these trials are successful - the vaccine widely available by the second half of 2021.
April 22: Germany announces the beginning of clinical trials for coronavirus vaccine
Germany's BioNTech and American partner Pfizer are given the green light from the Paul-Ehrlich Institute, the German authority for the certification of vaccines, to begin testing a variety of experimental vaccines on 200 healthy volunteers, aged between 18 and 55.
April 24: University of Oxford begins human trials for coronavirus vaccine
Tests of the ChAdOx1 nCoV-19 drug begin on 1,112 people divided into two groups (half of them receiving a vaccine and the other half a placebo), with the aim to stimulate their immune system to attack the virus.
The drug was created by using a chimpanzee virus which was genetically engineered to carry coronavirus. The UK government is funding the trial with a €51 million contribution.
May 13: France-US political row over vaccine priority
The French pharmaceutical giant, Sanofi causes a political firestorm by saying it would give the United States priority access to a vaccine as it was the first country to fund the research.
French Secretary of State for Economy and Finance Agnes Pannier-Runacher says it is "unacceptable," while prime minister Edouard Philippe summons Sanofi's CEO for reassurance over the vaccine's distribution.
May 22: University of Oxford/AstraZeneca vaccine enters phase two of its trial
Over 10,000 adults and children take part in phase two of their clinical trial, ten times more than the first phase which began in April.
This phase will study whether different age groups react differently to the vaccine.
A third phase is set to check whether the vaccine protects people from catching coronavirus by studying a large group of over-18s.
June 13: European countries partner up to strike huge vaccine deal
Pharmaceutical giant AstraZeneca says it has struck a deal with Germany, Italy, the Netherlands and France for the supply of up to 400 million doses of the vaccine the University of Oxford is trialling.
If it proves successful, delivery will begin by the end of 2020.
The British-Swedish company had already signed similar agreements with Britain, the US, the Norway-headquartered Coalition for Epidemic Preparedness Innovations (CEPI) and the international vaccine alliance Gavi.
An agreement had also been reached with the Serum Institute of India for 1 billion doses.
June 15: London's Imperial College announces beginning of human trials of vaccine
Three hundred healthy people participate in Imperial College's study by receiving two doses of a potential vaccine.
If the test shows a promising response, larger trials will take place later in the year with around 6,000 healthy volunteers.
The study is being financed with around €46 million from the UK government plus another €5.5 million coming from philanthropic donations.
June 16: Which potential vaccine is leading the race?
By June 16, out of 13 candidates, the vaccine at the most advanced phase of trials is the University of Oxford and AstraZeneca's ChAdOx1 nCoV-19 drug, with studies underway to determine "its efficacy, safety and immunogenicity".
The country working on the highest number of vaccines in a clinical phase by this point is China, followed by US, UK and Germany.
June 27: Ursula von der Leyen hails success of vaccines fundraising campaign
The EU Commission President says more than €6 billion were raised in the campaign launched with activist organisation Global Citizen and its virtual aid concert "Global Goal: Unite For Our Future". It brings the total raised by EU institutions to more than €16 billion.
June 27: Brazil secures up to 100 million doses of vaccine hopeful tested at the University of Oxford
Brazil signs a €113 million agreement with AstraZeneca for access to a vaccine hopeful being tested at the University of Oxford. The deal gives it the right to produce an initial quantity of 30 million doses in December and January when the vaccine is still in the testing phase.
If the vaccine passes clinical trials, Brazil will then be able to produce an additional 70 million doses at an estimated cost of €2.05 each.
The agreement includes the rights to access the vaccine technology and the manufacturing process.
The vaccine, called ChAdOx1 nCoV-19, is being tested in the UK, Brazil and South Africa.
July 1: 'Positive results' from BioNTech-Pfizer vaccine tests
Pfizer and BioNTech report their experimental BNT162b1 vaccine "is able to produce neutralising antibody responses in humans at or above the levels observed in convalescent sera – and that it does so at relatively low dose levels.".
The vaccine is being tested on 45 participants aged 18 to 55 in the US.
In this phase, the test is aimed at verifying that the vaccine is not toxic and triggers an immune system response against the virus. There are three other vaccine candidates being tested as part of the BNT162 program.
July 7: Novavax receives $1.6 billion from US government for 100 million vaccines
Novavax receives $1.6 billion (€1.4 billion) from the US government for developing a vaccine including a trial, manufacturing and 100 million doses of its vaccine candidate.
It's part of the US government's Operation Warp Speed, a programme that seeks to begin delivering millions of doses of a safe, effective vaccine for COVID-19 next year.
Regeneron Pharmaceuticals has received $450 million (€397 million) to make and supply its own COVID-19 vaccine candidate. The agreement supports continued manufacturing so that the product could be made available immediately in the US if clinical trials are successful.
July 10: UK rejects chance to join EU's COVID-19 vaccine scheme
The UK officially rejects the opportunity to join the European Union's coronavirus vaccine scheme.
Discussions had been "ongoing" between London and Brussels after the bloc reached out to the UK earlier this month to establish whether it wanted to cooperate on its approach to producing and distributing an effective COVID-19 vaccine.
But the UK government confirms on July 10 that it had decided not to participate in the scheme.
July 15: 'Good news': US hails results from trial
“No matter how you slice this, this is good news," says the US government's top infectious disease expert Dr Anthony Fauci, as positive results from a vaccination trial are released.
The trial, funded by the US National Institutes of Health and Massachusetts-based biotechnology company, Moderna Inc, found that the first 45 volunteers who underwent testing have developed neutralising antibodies in their bloodstream, at levels comparable to those who have survived COVID-19.
The trial is to enter a final stage around July 27, in a 30,000-person study, to find out if the injections are strong enough to protect against coronavirus.
July 15: Russia also reports positive results from a trial
A clinical trial at the Russian Ministry of Defence and the Nikolai Gamalaya Research Centre for Epidemiology and Microbiology has produced positive results, according to the Russian government.
The tests on military personnel and civilians show the vital functions of volunteers' bodies remained normal, says the Russian Ministry of Defence.
"Their immunity is good, the antibodies are being formed and they are protected against the coronavirus," says Svetlana Voltchikhina, a medical therapist who is co-leading the tests.
July 16: UK says Russia is behind cyberattack aimed at stealing vaccine research data
UK Foreign Secretary Dominic Raab accuses Russian agencies of trying to steal information related to research into a coronavirus vaccine. On July 19, Russia's Ambassador to the UK Andrei Kelin rejects the allegations, saying they make "no sense".
July 20: UK secures 90 million coronavirus candidate vaccine doses
The UK government signs a deal to buy 90 million doses of "promising coronavirus vaccine candidates" as the hunt for a COVID-19 vaccine continues.
This is in addition to an existing agreement with AstraZeneca and the University of Oxford to research, develop and manufacture a COVID-19 vaccine for the UK public.
"The hunt to find a vaccine is a truly global endeavour and we are doing everything we can to ensure the British public get access to a safe and effective coronavirus vaccine as soon as possible," said UK business minister Alok Sharma.
July 20: University of Oxford vaccine found to produce COVID-19 antibodies
Scientists at the University of Oxford say their experimental coronavirus vaccine has been shown in an early trial to prompt a protective immune response in hundreds of people who got the shot.
Scientists said that they found their experimental COVID-19 vaccine produced a dual immune response in people aged 18 to 55.
“We are seeing good immune response in almost everybody,” said Dr Adrian Hill, director of the Jenner Institute at Oxford University. “What this vaccine does particularly well is trigger both arms of the immune system.”
July 27: Biggest test yet of an experimental COVID-19 vaccine begins in the US
Thirty thousand volunteers take part in the final testing phase of a potential vaccine developed by US biotech company Moderna Inc and the National Institutes of Health (NIH).
The results are not expected before November, NIH's infectious-diseases chief said.
July 29: UK secures access to 60 million doses of COVID-19 vaccine candidate
The UK announced that it secured access to 60 million doses of a COVID-19 vaccine candidate from GlaxoSmithKline and Sanofi Pasteur.
It's based on the same technology used to produce Sanofi's flu vaccine, the UK government said.
"It is important that we secure early access to a diverse range of promising vaccine candidates, like GSK and Sanofi, to increase our chances of finding one that works so we can protect the public and save lives," business secretary Alok Sharma said.
The UK has already secured millions of doses of three other candidate vaccines.
August 11: Russia becomes first country to register a coronavirus vaccine
Russia was the first country in the world to register a coronavirus vaccine for use.
But many scientists in Russia and abroad questioned the decision to make the vaccine available for use before Phase 3 trials, which normally last for months and involve thousands of people.
August 14: EU secures 300 million doses of AstraZeneca vaccine
The European Commission signed a contract with Swedish-British pharmaceutical group AstraZeneca for 300 million doses of a potential vaccine, with an option for another 100 million additional doses.
Brussels had already obtained 300 million doses of a potential vaccine by French pharma company Sanofi, as well as another 400 million of the one studied by Johnson & Johnson, in the US.
August 28: UK to allow emergency use of any effective COVID-19 vaccine
The UK government said it was adopting “reinforced safeguards” to allow the country's medicines regulatory agency to grant temporary authorisation of a COVID-19 vaccine, provided it meets safety and quality standards.
The changes mean that people could be vaccinated before the vaccine is fully licensed but only after it's proven to be safe and effective.
September 3: Sanofi and GlaxoSmithKline say they will begin human trials of a vaccine
Sanofi and GlaxoSmithKline will begin human trials of a potential COVID-19 vaccine.
They will test the vaccine on 440 adults in the United States and expect first results in December.
The companies announced a collaboration with the US to produce up to 100 million doses of the vaccine and the British government has agreed to buy up to 60 million doses.