The results of the AstraZeneca/Oxford University coronavirus vaccine study have been long anticipated, and they follow researchers reporting positive preliminary trial results for other candidates.
Since the start of the pandemic, scientists around the world have been racing to develop a jab that prevents Covid-19.
And despite a number of candidates – including vaccines from Pfizer/BioNTech and Moderna – showing encouraging results, work on developing other options continues.
So what do we know about other vaccine candidates being developed?
At the start of November, Pfizer/BioNTech announced a major breakthrough in the race for a Covid-19 vaccine, with early phase three results suggesting the jab is 90% effective.
The researchers said this figure could change as the final results of the trial are analysed, but added that they would be applying for fast-track approval.
The companies hope to start distributing the vaccine – BNT162b2 – before the end of the year.
One week later, American company Moderna released interim analysis of its vaccine trial, saying the results suggest it may be 94.5% effective against Covid-19.
Moderna also released data relating to severe cases, indicating that all 11 severe cases that were observed occurred in the placebo group and none in the group which had received the vaccine, known currently as mRNA-1273.
Moderna said its available safety data does not indicate any significant safety concerns.
The phase three trial is continuing and the jab is yet to receive regulatory approval.
The UK is supporting and providing infrastructure to Novavax in running a phase three clinical trial.
The plans are to manufacture the vaccine in the UK with Fujifilm Diosynth Biotechnologies.
Clinical data for early phases of the trial suggested the vaccine triggers an immune response greater than that in patients who have recovered from the disease.
The company’s ongoing phase three clinical trial in the UK to evaluate the efficacy, safety and immunogenicity of NVX-CoV2373 is expected to be fully enrolled by the end of November.
Depending on the overall Covid-19 attack rate, interim data in the UK trial, which is also event-driven, are expected as soon as in the first quarter of next year.
Phase three trials of the Janssen vaccine started in mid-November with the aim of enrolling 6,000 people in the UK, and a total of 30,000 globally.
The jab has already undergone phase one and two trials, and interim analysis of the single-dose study suggests the Covid-19 vaccine candidate induces a robust immune response and is generally well-tolerated.
The UK researchers say the timing of results for their study will depend on global recruitment to the trial and the incidence of Covid-19.
They add that recent vaccine trials suggest it generally takes six to nine months to get an outcome, but it could be longer for trials starting out now.
The Imperial College London vaccine is in phase one of clinical testing, where doses are being given to a small group of people to determine whether it is safe and to learn more about the immune response it provokes.
Professor Robin Shattock, who is leading Imperial’s vaccine effort, said data on its efficacy will be available in the middle of next year.
Valneva’s site in Livingston, West Lothian, will manufacture the vaccine, and clinical trials are expected to start before the end of the year.
The company anticipates that it could potentially reach a first regulatory approval in the second half of 2021.
Early data for Russia’s coronavirus vaccine suggests it is 92% effective, the country’s sovereign wealth fund has said.
The announcement on the Sputnik V vaccine came days after pharmaceutical giant Pfizer/BioNTech announcement.
The phase three trials evaluated efficacy among more than 16,000 volunteers who received the vaccine or placebo 21 days after the first injection, but the analysis is based on only 20 confirmed cases of coronavirus.
Preliminary studies suggest a Chinese coronavirus vaccine candidate appears to be safe and induces an immune response in healthy volunteers.
Phase one/two trials of an inactivated Sars-CoV-2 vaccine candidate – CoronaVac – involved more than 700 healthy volunteers aged 18-59 recruited in China between April 16 and May 5.
According to preliminary results, the vaccine appeared to be safe and well tolerated at all tested doses.
Phase three trials of the vaccine are continuing.