Since the World Health Organisation (WHO) classified COVID-19 as a pandemic on March 11, scientists around the world have been racing to develop a vaccine that will allow life to return to normal. While experts had previously predicted a vaccine would become widely available by mid-2021, there have been promising results in the Pfizer and BioNTech trials that indicate that access to a coronavirus vaccine in the UK could be earlier. Here’s what we know so far…On Nov. 9, the vaccine developed by U.S. pharmaceutical firms Pfizer and BioNTech was reported to offer 90% protection against COVID-19. This statistic was based on early analysis; the trial reportedly included 43,538 people across six different countries. The results are being hailed as a "much-needed breakthrough" by Pfizer’s chairman and chief executive Dr Albert Bourla, and scientists have highlighted the results as a positive step in the right direction, though there’s still work to be done before the vaccine becomes widely available. It's one of 11 vaccines worldwide that are reportedly in the final stages of testing.Per the BBC, Boris Johnson has said that we should not "rely on this news as a solution" as it is still "very, very early days". The vaccine will not be released for use in the UK until it passes final safety tests and gets the go-ahead from the government's Medicines and Healthcare products Regulatory Agency.On Nov. 10, the BBC reported that the vaccine could be available for a limited number of people by Christmas, but Health Secretary Matt Hancock expected the mass-roll out to be "in the first part of next year". Speaking on BBC Breakfast, Hancock said: "The NHS is ready, we're prepared, I've put in the extra £150m today, the GPs are ready, we're working with the pharmacists, the hospitals are going to play a very important role." The BBC reports that the UK has already ordered 40 million doses, which would be enough to vaccinate up to 20 million people (each person will need two doses for it to work effectively).When asked how many people would need to be vaccinated Hancock said: "So the trials can tell you if a vaccine is clinically safe and if it's effective at protecting an individual from the disease. What we can't know, until we've vaccinated a significant proportion of the population, is how much it stops the transmission of the disease."Older groups are at the top of the government's priority list for the first to receive the vaccine and Hancock said it would not be given to children. However, per the BBC, Sir John Bell a professor from Oxford University said: "I would worry about not giving this to as wide a percentage of the population as we can. I'm more of the view that we need to vaccinate further into the population and vaccinate younger people as well, partly because we don't really know what the long term effects of this disease are."There’s also the possibility that any potential new vaccine will have to be rolled out twice a year, as findings in a study conducted by Imperial “suggested a ‘rapid’ decline in immunity” in just three months, per The Telegraph.A vaccine in the normal sense of the word works by training the immune system to recognise and combat pathogens, from either viruses or bacteria. To do this, certain molecules from the pathogen are introduced into the body via the vaccine to trigger an immune response.The vaccine that currently appears to be the closest to being widely available, by Pfizer BioNtech, is known as an RNA vaccine. Per University of Cambridge think tank PHG Foundation, "Unlike a normal vaccine, RNA vaccines work by introducing an mRNA sequence (the molecule which tells cells what to build) which is coded for a disease specific antigen, once produced within the body, the antigen is recognised by the immune system, preparing it to fight the real thing." In August the government reported that over 100,000 people had volunteered to take part in the UK’s COVID-19 vaccine trials, and continue to encourage people to sign up to the National Institute for Health Research’s (NIHR) COVID-19 Vaccine Research Registry to volunteer for one of the “large-scale vaccine studies” taking place across the country.Scientists are trialling on volunteers from “all parts of society,” and especially those who are “more likely” to benefit from a vaccine; including the over 65s, frontline health and social care workers, and those from Black, Asian, and minority ethnic backgrounds.On Monday 9 Nov. the Novavax vaccine (by a U.S. biotech firm) was granted a fast-track designation by the U.S. Food and Drug administration, which should accelerate its development. Phase 3 trials of the Novavax vaccine have been underway in the UK since October, involving up to 10,000 participants aged 18 to 84 years old.Vaccine trials on humans began in the UK at the end of April at the University of Oxford in partnership with British-Swedish company AstraZeneca. This vaccine moved to Phase 3 testing on Sept. 3, which involved some 30,000 participants in the U.S. as well as in the UK, Brazil, South Africa, and Kenya. Despite being brought to a halt on Sept. 8 after a volunteer from the UK trial was diagnosed with transverse myelitis, the trial has restarted in Britain, Brazil, India and South Africa, but remain paused in the U.S. “where the legal and historical context means regulators tend to take a tougher stance,” per theTelegraph.The BBC reported in July that the government has already signed a deal for 100 million doses of the vaccine being developed by AstraZeneca and Oxford University. While trials are going well, it was reported on Nov. 4 by the Guardian that the research team at Oxford told MPs there’s only a “small chance” this vaccine will be ready in time for Christmas.On Nov. 7 the Independent reported that participants in the Oxford trials had been sharing their swabs with family and friends. Some of the positive test results were traced back to people not involved in the study. However, Oxford University confirmed this would not affect overall results.A round of human trials began in early July at Imperial College London, with 300 people being screened for the trial and first doses being administered to 15 trial volunteers. On July 17, it was announced that Imperial would be moving into their next round of trials.In October, Imperial agreed to collaborate with Indonesia on vaccine research and education, as well as the development “of a self-amplifying RNA vaccine platform.” This future platform would enable Imperial “to create novel vaccines against future pandemics within eight weeks — a step that currently takes months to years,” professor Robin Shattock said in a statement published by Imperial.If the trials “continue to show promising results”, Imperial plans on commencing international trials of their vaccine later this year “with potential improvement for the vaccine by mid-2021,” Shattock added.In September, the Guardian reported that the world’s largest vaccine makers GlaxoSmithKline (GSK) and Sanofi were to start testing their protein-based Covid-19 vaccine on humans for the first time. GSK are also developing a potential antibody treatment, which entered its third phase on Oct. 6. The pharmaceutical giants joined forces back in April to combine their existing technology to create a flu vaccine. On July 30, the government announced that an agreement with the two drugs companies would result in 60 million doses of their vaccine being supplied to the UK.In addition to this national supply, GSK and Sanofi announced on Oct. 29 that they will provide 200 million doses of their vaccine to the Covax scheme, a global inoculation plan backed by the World Health Organisation (WHO).On Nov. 10, BBC reports said Russia is hoping to combat a second wave with one of several COVID-19 vaccines that has been developed there, Sputnik V. When the Pfizer BioNtech vaccine pledged to be 90% effective, Russia's health ministry claimed the same was true of Sputnik V and suggested a mass-vaccination scheme was imminent, despite the fact it is still mid-trials. China approved early-stage human tests for two experimental coronavirus vaccines back in April 14. One vaccine, developed by biotech firm CanSino Biologics and the Beijing Institute of Biotechnology, is now firmly in its phase two trial. Meanwhile the development of another vaccine in China by Sinovac Biotech reportedly entered phase 3 of trials in July, per Reuters.More testing is also being conducted in South Africa, Japan and Australia. In October Pfizer and BioNTech started a roll out of Phase 3 testing in South Africa. Further information about the U.S. progress on finding a coronavirus vaccine can be found here.Contributions from Orla Pentelow, Sophie McEvoy, and Alice Broster.