This live article contains regularly updated information on the experimental vaccines being developed for COVID-19.

  • COVID-19 is a respiratory disease caused by the SARS-CoV-2 virus.
  • Researchers across the globe are working to develop a vaccine.
  • Currently, there are 57 candidate vaccines on trial in 37 countries.
  • Today, there are 12 candidate vaccines in stage 3 clinical trials.
  • For general COVID-19 updates visit our live blog.

11/23/2020 09:52 GMT — AstraZeneca’s ‘Oxford’ vaccine 70% effective
According to a recent press release, the experimental COVID-19 vaccine developed by AstraZeneca and Oxford University prevents just over 70% of people from developing COVID-19. Although this is lower than the Pfizer and Moderna vaccines, using a different dosing regimen may increase the protection to 90%.
The recent announcement is based on data from 24,000 participants in three countries. Importantly, the Oxford vaccine is more cost effective to produce and easier to store and transport than the Pfizer and Moderna vaccines.
The so-called Oxford vaccine trial tested two dosing regimens:

  • two full doses, which provided 62% protection
  • one half dose followed by one full dose, which provided 90% protection

Prof. Andrew Pollard, the director of the Oxford Vaccine Group, explains:
“These findings show that we have an effective vaccine that will save many lives. Excitingly, we’ve found that one of our dosing regimens may be around 90% effective, and if this dosing [regimen] is used, more people could be vaccinated with planned vaccine supply.”
Dr. Stephen Griffin, an associate professor in the School of Medicine at the University of Leeds, U.K., says:
“This is yet more excellent news and should be considered tremendously exciting. The Oxford vaccine, as for the others we’ve heard about recently, is capable of generating 90% protection against COVID-19. Given the favorable stability seen for this vaccine, it has great potential to be delivered across the globe, achieving huge public health benefits.”
Dr. Griffin was not involved with the study.
Read more here.
11/19/2020 10:31 GMT — Pfizer and BioNTech COVID-19 candidate vaccine is 95% effective
In a recent press release, Pfizer and BioNTech announced the results from their phase 3 clinical trial. According to the results, the experimental vaccine is 95% effective. These results build on preliminary results that were announced last week.
According to the new press release, “[e]fficacy was consistent across age, gender, race, and ethnicity demographics” and in people over 65. 
The study included 43,000 participants and the scientists identified no significant safety concerns. The researchers have dubbed their mRNA vaccine candidate BNT162.
According to the press release, “[t]he companies expect to produce, globally, up to 50 million vaccine doses in 2020 and up to 1.3 billion doses by the end of 2021.”
Read more here. 
11/18/2020 09:18 GMT — Hopeful preliminary results from Chinese vaccine trials
Yesterday, The Lancet Infectious Diseases published the results of a Phase 1/2 clinical trial on a vaccine candidate designed in China. The study included more than 700 participants, aged 18–59. The vaccine, which is called CoronaVac, appears to be safe and elicit an immune response.
The researchers gave the participants two doses of the vaccine 2 weeks apart. Within 4 weeks of the initial dose, they detected a robust antibody response.
It is worth noting that this study was not designed to test how effective the vaccine is. Instead, it assessed the immune response and the vaccine’s safety. Ongoing phase 3 trials are studying CoronaVac’s efficacy.
The results leave some questions unanswered; for instance, the recent study did not assess T-cell activity. The authors are addressing this question in the phase 3 trials.
Similarly, scientists will need to carry out further research to understand whether the vaccine is effective over months and years. Additionally, the recent study only recruited healthy adults without existing health conditions.
One of the authors, Dr. Gang Zeng from Sinovac Biotech explains, “CoronaVac is one of many COVID-19 vaccine candidates that are being explored in parallel. There are a multitude of different vaccine technologies under investigation, each with their own advantages and disadvantages.”
He continues: “CoronaVac could be an attractive option because it can be stored in a standard refrigerator between 2°C and 8°C [35.6°F–46.4°F], which is typical for many existing vaccines, including [that for the] flu. The vaccine may also remain stable for up to 3 years in storage, which would offer some advantages for distribution to regions where access to refrigeration is challenging. However, data from phase 3 studies will be crucial before any recommendations about the potential uses of CoronaVac can be made.”
Read the full study here.
11/16/2020 13:15 GMT — Moderna’s experimental vaccine almost 95% effective
Today, Moderna released the latest findings from their COVE study. The research focuses on an experimental vaccine known as mRNA-1273. According to their press release, the “[p]hase 3 study met statistical criteria with a vaccine efficacy of 94.5%.” The U.S. study included more than 30,000 participants.
Explaining the results, the press release states: 
“This first interim analysis was based on 95 cases, of which 90 cases of COVID-19 were observed in the placebo group versus 5 cases observed in the mRNA-1273 group, resulting in a point estimate of vaccine efficacy of 94.5% […]. A secondary endpoint analyzed severe cases of COVID-19 and included 11 severe cases (as defined in the study protocol) in this first interim analysis. All 11 cases occurred in the placebo group and none in the mRNA-1273 vaccinated group.”
The company plan to submit the new findings to a peer-reviewed journal for further scrutiny.
Speaking about the recent results, Prof. Peter Openshaw, professor of experimental medicine at Imperial College London, says, “This news from Moderna is tremendously exciting and considerably boosts optimism that we will have a choice of good vaccines in the next few months.”
However, he remains cautious: “We need more complete details than we have in this press release, but this announcement adds to the general feeling of optimism about vaccines for Covid-19. What we still don’t know is how long any protective immunity may last. For that, we will need to wait.”
Prof. Stephen Evans, professor of pharmacoepidemiology at the London School of Hygiene & Tropical Medicine says:
“This announcement from Moderna is a further encouragement that vaccines will be found to not only have an acceptable efficacy but an efficacy that is much greater than we had anticipated. […] Although they reported efficacy being over 94%, there is statistical uncertainty in this; but based on these data, the likely efficacy will be better than 85%, which would be greater than most scientists would have expected.”
Read more about Moderna’s experimental vaccine here.
11/13/2020 15:00 GMT —Dr. Fauci: Another vaccine ‘literally on the threshold of being announced’
In a live webinar hosted by the British think tank Chatham House, Dr. Anthony Fauci explained that, in addition to the Pfizer vaccine, another one is “literally on the threshold of being announced.”
The news comes soon after Pfizer/BioNTech reported their vaccine candidate has 90% effectiveness. The additional vaccine that Dr. Fauci refers to is under development by Moderna therapeutics and is almost identical to the Pfizer one.
“The cavalry is coming, but don’t put your weapons down,” Dr. Fauci said, urging people to continue to follow and “double down” on the public health measures against COVID-19.
Watch the recording of the webinar in full here.
11/12/2020 09:30 GMT —More vaccine updates
Russia has announced that the first phase 3 trial interim analysis of their Sputnik V COVID-19 vaccine showed 92% efficiency. However, many questions remain. Meanwhile, Moderna announced that they would be submitting the first set of their phase 3 trial vaccine data for analysis soon.
This week saw announcements from three of the companies who are currently running phase 3 trials of their vaccine candidates. 
On Monday, Pfizer and BioNTech announced that their experimental mRNA vaccine was 90% effective. This was based on an interim analysis of 94 cases of COVID-19.
Yesterday, the Gamaleya National Center of Epidemiology and Microbiology announced that their interim analysis, based on 20 confirmed cases of COVID-19, showed a 92% efficiency. 
However, neither Pfizer nor the Russian team have shared their data, which leaves many questions unanswered.
Moderna have followed suit with a press release explaining that they had seen an increase of COVID-19 cases across all of their phase 3 trial study sites in the last week. The company have now collected enough data to prepare this for the first interim analysis.
Read more detail on the different types of vaccine candidates in development here.
11/10/2020 09:21 GMT — COVID-19 vaccines: What PAHO experts want you to know
With 47 COVID-19 vaccine candidates currently in testing, it is no wonder that myths and rumors are circulating. Recently, experts from the Pan American Health Organization (PAHO) addressed some of these confusions in a webinar.
Read MNT’s full coverage of the webinar here.
11/09/2020 13:06 GMT — Pfizer and BioNTech announce preliminary vaccine results
Today, Pfizer and BioNTech announced that their COVID-19 vaccine candidate appears to be effective and safe, according to preliminary data. They explain that the vaccine was “more than 90% effective” in preventing the disease in people who received two doses of the vaccine 3 weeks apart. 
They showed that protection against COVID-19 begins 1 week after the second dose is administered.
It is important to reiterate that these are preliminary findings. However, so far, they include data from 43,538 people in six countries. The press release also explains that “no serious safety concerns have been observed.”
To date, the analysis includes data from 94 people with COVID-19. The study will continue until there are 164 confirmed cases.
Once the required safety milestone is reached, toward the end of November, the companies plan to submit the vaccine for Emergency Use Authorization to the Food and Drug Administration (FDA).
“The first interim analysis of our global Phase 3 study provides evidence that a vaccine may effectively prevent COVID-19. This is a victory for innovation, science, and a global collaborative effort,” said Prof. Ugur Sahin, co-founder and CEO of BioNTech.
“With today’s news, we are a significant step closer to providing people around the world with a much-needed breakthrough to help bring an end to this global health crisis. We look forward to sharing additional efficacy and safety data generated from thousands of participants in the coming weeks.”
Read more here.
11/02/2020 10:28 GMT — Surgeon General predicts vaccine by the end of 2020
During a recent lecture, Dr. Jerome Adams, the U.S. Surgeon General, said he has “a high degree of confidence” that a vaccine will be successful because it is “the most scrutinized vaccine of all time.” He believes it will be ready by the end of 2020.
During the lecture — part of the Department of Anesthesiology and Perioperative Medicine’s Grand Rounds series — he promoted the “three Ws” — wearing masks, washing hands, and watching your distance from other people.
“We know what works to keep people safe,” he said. “When you look at New York, they were the worst in the world for COVID-19, and they were able to drive their transmission rates down to less than 1%. They didn’t have a vaccine; they did it with the three Ws.”
Read more here.
10/30/2020 09:09 GMT — Vaccine may be ready by January2021
According to Dr. Anthony Fauci, a vaccine may be available by early next year. First, it would be provided to high risk individuals. Based on projections from Moderna and Pfizer, Dr. Fauci expects that we will know “sometime in December whether or not we have a safe and effective vaccine.” 
In July, both Moderna and Pfizer began late stage trials involving tens of thousands of participants. However, Dr. Fauci also reminds us that even once a vaccine is ready, a return to “normal” will not be possible “until the end of 2021, at least.”
Read more here.
10/26/2020 10:27 GMT — AstraZeneca’s ‘Oxford vaccine’ moves forward
An experimental vaccine, developed by scientists at the University of Oxford in the United Kingdom and AstraZeneca, recently passed another milestone. In July, the team announced that the experimental drug produced “robust immune responses” in adults. Today, they report that the experimental vaccine responds similarly in older adults and young people.
The scientists are yet to publish their findings in a peer-reviewed journal, but Prof. John Ball from the University of Nottingham, U.K., who was not involved in the study, is hopeful. He told the Financial Times:
“If what they’ve got is data that show the vaccine generates good immunity, as measured in the lab, in the age group over 55, and that also includes good responses in people who are even older than that, I think that’s a promising sign.”
However, he remains realistic, explaining that, “ultimately, it’s whether the vaccine protects against serious disease that’s crucial and we will only know that from phase 3 trials.”
Read more here.
10/23/2020 09:13 GMT — What will COVID-19 vaccine trials tell us? Less than some may think
What will COVID-19 vaccine candidate trials tell us? Not whether they will prevent deaths or serious illness, according to a new article in the BMJ. The feature highlights precisely what these trials do and do not set out to answer.
Read MNT’s full write up here.
10/21/2020 08:58 GMT — UK scientists plan to infect participants with SARS-CoV-2
Scientists in the United Kingdom are planning to infect young and healthy volunteers with SARS-CoV-2. The U.K. government will spend $43.5 million on these human challenge trials. If regulators and the ethics committee approve, they will begin early in 2021.
London’s Great Ormond Street Hospital plan to manufacture the virus, while Imperial College London will run the research. The trials will also involve hVIVO, a company that provides “viral challenge studies and laboratory services;” and the Royal Free London NHS Foundation Trust.
Involving up to 90 participants, the scientists plan to work out the minimum amount of virus sufficient to induce COVID-19.
According to Imperial College scientist Chris Chiu, this work will improve our understanding of SARS-CoV-2 and accelerate the search for better treatments and vaccines.
Speaking about the ethical considerations, a spokesperson from the World Health Organization (WHO) said:
“What is critical is that if people are considering this, an ethics committee must oversee this and the volunteers must have full consent. And they must select the volunteers to minimize their risk.”
Read more about COVID-19 research here.
10/16/2020 09:25 GMT — Russia approves a second vaccine
Last month, Russia announced the approval of a COVID-19 vaccine known as Sputnik V. This week, President Vladimir Putin announced the approval of another vaccine, which is called EpiVacCorona. As with the first, scientists have not yet put the experimental vaccine through phase 3 trials.
The vaccine was developed by scientists at the State Virology and Biotechnology Center, known as Vektor, in Novosibirsk. According to The Moscow Times:
“Early trials on 100 volunteers were said to have been successful.”
In a televised news conference, Putin explained that researchers had given the vaccine to Deputy Prime Minister Tatyana Golikova and the head of Russia’s consumer safety watchdog, Anna Popova, as part of ongoing trials. During the briefing, they explained that:
“Early trials on 100 volunteers were said to have been successful.”
As with Sputnik V, experts are likely to view the new vaccine with caution. Vaccines must be rigorously investigated before they can be used widely, and it is crucial to test their efficacy and safety in a large group of people.
Sputnik V is a vector vaccine, based on a human adenovirus, while EpiVacCorona is an antigen-based vaccine.
During the briefing, Golikova also announced that a third vaccine would be approved sometime toward the end of 2020x.
Read more here.
10/13/2020 10:35 GMT — Johnson & Johnson pause vaccine trial
In a statement, Johnson & Johnson announced they had paused their experimental vaccine trial “due to an unexplained illness in a study participant.” The participant’s illness is now under review with an independent safety board and the company’s clinical and safety physicians. 
The Janssen COVID-19 vaccine is part of the Operation Warp Speed program.
In the press release, Johnson & Johnson explain that serious adverse events are “not uncommon in clinical trials,” especially when a study has recruited large numbers of participants. To date, the company has not released any further information about the participant’s illness.
Find more live updates here.
09/24/2020 09:33 GMT — Most people in the United States could be vaccinated by July next year
Despite promising candidates, there is still no vaccine for COVID-19. However, according to Robert Redfield — the head of the Centers for Disease Control and Prevention (CDC) — the “entire American public [could be] completely vaccinated” by July. He estimates that 700 million doses will be available by April.
Read more here.
9/15/2020 09:58 GMT — Chinese vaccine ready by November?
According to officials in China, a COVID-19 vaccine could be ready by the end of November. Scientists are currently testing four candidate vaccines in late-stage clinical trials, and three of these have already been offered to frontline staff.
According to Guizhen Wu, the chief biosafety expert at China’s Centers for Disease Control and Prevention (CDC), phase 3 clinical trials are going well.
Read more here.
09/10/2020 09:18 GMT — Promising results for Russian vaccine
A new paper in The Lancet outlines the findings of two early phase clinical trials of the Russian vaccine known as Sputnik V. According to the authors, the vaccine “has a good safety profile and induced strong humoral and cellular immune responses in participants.”
It is worth noting, though, that the trials were designed to assess the safety and immunogenicity of the vaccine, not whether it can prevent COVID-19. Senior author Prof. Alexander Gintsburg explains the next steps:
“The phase 3 clinical trial of our vaccine was approved on 26 August, 2020. It is planned to include 40,000 volunteers from different age and risk groups and will be undertaken with constant monitoring of volunteers through an online application.”
Read MNT’s full coverage of the vaccine trial here.
09/14/2020 10:53 GMT — AstraZeneca resume vaccine trial
Last week, AstraZeneca paused a trial investigating an experimental vaccine. The move came following an illness in one participant. Following a review, the scientists are resuming the trial. The World Health Organization (WHO) have described this vaccine as a leading candidate.
In a recent statement, AstraZeneca state, “The independent review process has concluded, and following the recommendations of both the independent safety review committee and the U.K. regulator, the [Medicines and Healthcare products Regulatory Agency], the trials will recommence in the U.K.”
Read more about the clinical trial here.
09/09/2020 08:32 GMT — AstraZeneca’s COVID-19 vaccine trials halted
According to AstraZeneca Plc., they paused a large-scale clinical trial of an experimental vaccine because one participant developed an unexplained illness. The World Health Organization (WHO) had described this vaccine, developed at the University of Oxford in the United Kingdom, as a leading candidate.
AstraZeneca has halted trials while an independent committee reviews the safety data. In a statement, the company explain: “This is a routine action, which has to happen whenever there is a potentially unexplained illness in one of our trials.”
Although AstraZeneca has not disclosed the nature of the participant’s illness, doctors expect the individual to recover. At this point, it is not clear whether the vaccine was directly responsible for the condition.
Read more here.
09/02/2020 09:59 GMT — Third US vaccine reaches final trial stages
Today, AstraZeneca announced that their experimental vaccine had entered the final stage of testing. The upcoming study will involve up to 30,000 people in Brazil, the United Kingdom, and South Africa. The vaccine was developed at the University of Oxford in the U.K.
Read more here.
For live updates on the latest developments regarding the novel coronavirus and COVID-19, click here.