Photograph by Victoria Jones, AP
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Dr. Doreen Brown, 85, receives the first of two Pfizer-BioNTech COVID-19 vaccine jabs administered at Guy's Hospital in London, Tuesday, Dec. 8, 2020. U.K. health authorities rolled out the first doses of a widely tested and independently reviewed COVID-19 vaccine Tuesday, starting a global immunization program that is expected to gain momentum as more serums win approval.

Photograph by Victoria Jones, AP

Here’s the latest on COVID-19 vaccines

These are the COVID-19 vaccine prospects that have made it to phase three trials and beyond.

  • The Biden Administration announced its intention to join the COVAX Facility, a global initiative led by the World Health Organization to ensure the equitable distribution of COVID-19 vaccines.
  • The WHO is reportedly close to granting emergency use approval to the Moderna, AstraZeneca-Oxford, Sinopharm, and Sinovac vaccines. It has already approved the Pfizer-BioNTech vaccine.

COVID-19 vaccines have reached consumers in record time. Though the process can typically take 10 to 15 years, the U.S. Food and Drug Administration has granted emergency authorization to vaccines made by Pfizer and Moderna in less than a year. Before now, the fastest-ever vaccine—for mumps—took four years to develop in the 1960s.

Yet even after a vaccine is authorized or fully licensed, it faces potential roadblocks when it comes to scaling up production and distribution, which also includes deciding which populations should get it first—and at what cost. CDC director Robert Redfield, vaccine developers, and the FDA have said it’s unlikely COVID-19 vaccines will be widely available until the middle of 2021. (Here's why determining who is “first in line” for the vaccine depends on your state.)

Yet several efforts are underway to help produce and distribute the vaccines more quickly. Here’s everything you need to know—including primers on how vaccines and clinical trials work, the latest news on vaccine distribution and safety, and a detailed breakdown of each of the candidates that have reached phase three and beyond.

Vaccines and clinical trials

More than 60 vaccines are still going through a three-stage clinical trial process that’s required before they are sent to regulatory agencies for approval. Given the urgent need, some vaccine developers have compressed the clinical process for SARS-CoV-2 by running trial phases simultaneously.

The COVID-19 candidates, like all vaccines, essentially aim to instruct the immune system to mount a defense, which is sometimes stronger than what would be provided through natural infection and comes with fewer health consequences.

To do so, traditional vaccines use the whole coronavirus, but in a killed or weakened state. Others use only part of the virus—whether a protein or a fragment. Some transfer the instructions for coronavirus proteins into an unrelated virus that is unlikely or even incapable of causing disease. Finally, cutting-edge vaccines under development rely on deploying pieces of the coronavirus’s genetic material, enabling our cells to temporarily make coronavirus proteins needed to stimulate our immune systems. (Find out more about vaccines and how they work.)

Vaccine rollout and safety

On January 21, U.S. President Joe Biden released his administration’s strategy for a $1.9 trillion COVID-19 rescue plan, which includes $20 billion to mount a national vaccination program. States will still be responsible for rollout decisionmaking, which has caused confusion and uncertainty as the states differed in their vaccine priorities. But Biden is urging them to expand eligibility to frontline workers and people age 65 and older. Biden’s plan also calls for launching community vaccination centers and deploying mobile vaccination units to hard-to-reach areas, as well as free vaccines for all people in the U.S. regardless of immigration status. Pediatrician and former U.S. Food and Drug Administration head David Kessler will lead the U.S. plan to accelerate the development and rollout of vaccines for COVID-19.

The World Health Organization is also coordinating global efforts to develop a vaccine, with an eye toward delivering two billion doses by the end of 2021. On January 21, the Biden Administration said it intends to join the COVAX Facility, the WHO-led initiative to ensure that all countries have equitable access to the vaccine. Under the Trump Administration, the U.S. had been one in a handful of countries refusing to participate. The WHO has approved the Pfizer-BioNTech vaccine for emergency use and is reportedly in late stages of reviewing the candidates from Moderna, AstraZeneca-Oxford, Sinopharm, and Sinovac.

As of January 21, the U.S. had administered more than 17 million doses of the two authorized vaccines made by Pfizer-BioNTech and Moderna and had distributed nearly 38 million doses.

A CDC report released January 6 revealed that severe reactions to the Pfizer-BioNTech COVID-19 vaccine are rare, offering reassurances of safety as efforts for wide-spread vaccination continue to ramp up. However, in a January 15 press release, Norwegian officials urged caution in vaccination of people more than 80 years old or with serious underlying diseases. Out of 33,000 doses given so far in Norway, the country recorded 23 deaths with suspected ties to the COVID-19 vaccine. Autopsies of 13 of these individuals suggest that common side effects led to a severe reaction.

Vaccine prospects

Here are the vaccines that have made it to phase three and beyond:


Who: An Indian biotechnology company, in collaboration with the Indian Council of Medical Research and the National Institute of Virology.

What: An inactivated vaccine, which requires two doses that are administered 28 days apart.

Latest news: On January 21, The Lancet published interim findings from COVAXIN’s phase one study that showed the vaccine elicited an immune response in participants. The study identified only one serious adverse event, and it was unrelated to the vaccine. The biotechnology company has not yet published data from its ongoing phase three trials but said in a statement that the vaccine “has generated excellent safety data with robust immune responses.”

Approval status: Authorized for emergency use in India.

Distribution: India has the second-highest caseload in the world—only behind the U.S.—with more than 10 million people infected. As a result, the country is embarking on an ambitious plan to vaccinate 300 million frontline workers and vulnerable people by August 2021.

On January 12, Bharat Biotech announced that it had signed an agreement with Precisa Medicamentos, a Brazilian pharmaceutical company, to sell COVAXIN in Brazil.

Efficacy and safety: Results posted online in September but not yet peer reviewed show that the vaccine produced antibodies in monkeys. Bharat Biotech Executive Director Sai Prasad also told Reuters in October that preliminary results from early vaccine trials found more than 90 percent of human participants developed antibodies.

Clinical trials status: On November 16, Bharat Biotech announced it has begun phase three trials involving 26,000 participants at more than 25 centers across India.

Name: None

Who: China’s state-run pharmaceutical company, in collaboration with the Wuhan Institute of Biological Products.

What: Two inactivated SARS-CoV-2 vaccines.

Latest news: On January 21, Pakistan’s foreign minister announced that China has agreed to provide them half a million doses of the Sinopharm vaccine for free by January 31. Pakistani regulators approved the vaccine for emergency use earlier in the week.

Distribution: Authorities in China have set a goal to vaccinate 50 million people by Lunar New Year in mid-February, despite the lack of evidence that their available vaccines are safe and effective. Chinese officials have said the vaccine will be free for Chinese citizens, and that they will prioritize immunizations for high-risk groups such as the elderly and people with underlying conditions.

On January 13, Hungary’s government announced that it had reached a deal with Sinopharm to buy the company’s vaccine, following Hungary’s criticisms of the pace of the European Commission’s vaccine rollout.

Approval status: China has approved one of the company’s vaccines for general use and another for limited use. One of the Sinopharm vaccines has also been approved in Bahrain, the United Arab Emirates, and other countries.

Sinopharm filed for final regulatory approval from China in late November, two months after the New Yorker reported that hundreds of thousands of Chinese civilians have already been vaccinated under the government’s emergency-use approval. China began to innoculate medical workers and other high-risk groups with the Sinopharm trial vaccines in July, making it the first experimental vaccine available to civilians beyond clinical volunteers.

Efficacy and safety: On December 30, the company announced results of its phase three study showing one of its vaccines to be 79-percent effective in preventing COVID-19. The company did not provide any data backing up its claim. In its earlier approval of a Sinopharm vaccine, the UAE said that an interim analysis of the phase three study showed the candidate is 86-percent effective in preventing COVID-19 with no serious safety concerns. UAE officials also claimed the vaccine is 100-percent effective in preventing moderate and severe cases of the disease.

Preliminary findings from two randomized trials, published in the Journal of the American Medical Association, have shown the vaccine can trigger an antibody response with no serious adverse effects. The study did not measure T cell-mediated immune responses. These results are significant, though, as they are the first published data from human clinical trials for a COVID-19 vaccine that uses a whole, inactivated virus.

Clinical trials status: Sinopharm launched its first phase three trial in July among 15,000 volunteers—aged 18 to 60, with no serious underlying conditions—in the UAE. The company selected the UAE because it has a diverse population made up of approximately 200 nationalities, making it an ideal testing ground. Sinopharm will also undertake phase three trials in locations such as Peru and Bahrain.

Name: mRNA-1273

Who: A Massachusetts-based biotech company, in collaboration with the National Institutes of Health.

What: A nucleic-acid vaccine that requires two doses, four weeks apart.

Latest news: On January 8, the U.K. approved the use of Moderna’s vaccine, making it the third vaccine available in the country.

Approval status: On December 18, the FDA granted emergency approval to Moderna’s COVID-19 vaccine, a day after an advisory panel decided 20-0, with one abstention, that the benefits of the vaccine outweigh the risks, such as the mild side effects reported in their clinical trial. The vaccine has also been approved in the European Union, Canada and Israel.

Distribution: Moderna has begun shipping the first 5.9 million doses. It is the second vaccine to receive emergency authorization in the U.S., joining Pfizer’s candidate, which was approved a week earlier.

On December 11, the Trump Administration purchased an additional 100 million doses of Moderna’s vaccine for a total of 200 million doses before the end of June 2021. Moderna expects to have 20 million doses ready to ship in the U.S. by the end of the year. The company also says it remains on track to deliver at least 500 million doses globally per year beginning in 2021, thanks in part to a deal it has struck with Swiss manufacturer Lonza that will allow it to manufacture up to a billion doses a year. The company said its vaccine can be safely stored on ice or in a normal refrigerator for 30 days.

Efficacy and safety: The FDA has also published an analysis of the phase three study of Moderna’s vaccine. It confirms the company’s claims that its candidate is 94.1-percent effective in preventing mild cases of COVID-19 and 100-percent effective at preventing severe cases after taking two doses.

Moderna announced on December 22 that it plans to test how well its vaccine works against the new variant of the virus that’s been found in the U.K.

Clinical trials status: Moderna announced on December 17 that it is launching clinical trials to evaluate the vaccine’s safety in children and people with cancer; it will also establish a “pregnancy registry” to track the vaccine’s safety in people who are pregnant.

The company started the third phase of its clinical trials in July. Preliminary findings from its phase one trials showed that healthy subjects—including elderly patients—produced coronavirus antibodies and a reaction from T cells, another part of the human immune response. Phase three is testing the vaccine in 30,000 U.S. participants. The company also announced plans to test the safety and efficacy of a booster shot that would be delivered a year after the first pair of vaccine doses, according to CNBC. The trial will likely begin in July 2021.

Name: CoronaVac

Who: A Chinese biopharmaceutical company, in collaboration with Brazilian research center Butantan.

What: An inactivated vaccine.

Latest news: On January 11, Indonesia’s food and drug agency gave emergency use authorization to Sinovac’s vaccine and began administering it two days later. News of the rollout follows the January 8 move by Indonesia’s highest Islamic body to give religious approval to CoronaVac. The country had already received a total of three million doses of the vaccine.

Approval status: Approved for limited use in China and Indonesia.

Efficacy and safety: Reports released in early January place CoronaVac’s efficacy below that of other authorized vaccines. A late-stage clinical trial in Indonesia found CoronaVac’s efficacy rate to be 65.3 percent. On January 7, Brazilian officials announced that an in-country trial of the vaccine pointed to an efficacy of 78 percent. However, results from the trial released on January 13 found that CoronaVac had an efficacy of 50.4 percent, slightly more than the 50-percent minimum recommended by the World Health Organization. The difference comes down to the earlier estimate’s exclusion of trial participants who got “very mild infections” but did not require clinical assistance.

On November 17, preliminary results from Sinovac’s early trials, published in The Lancet, reported that the vaccine was safe but produced only a moderate immune response, with lower levels of antibodies compared to those in patients who have recovered from COVID-19. Preliminary results in macaque monkeys, published in Science, revealed that the vaccine produced antibodies that neutralized 10 strains of SARS-CoV-2.

Clinical trials status: CoronaVac entered phase three trials in July, with plans to recruit nearly 9,000 healthcare professionals in Brazil, in addition to phase three trials in Indonesia. A planned trial in Bangladesh was delayed, after Bangladesh refused in October to co-finance a late-stage trial.

Name: ChAdOx1 nCoV-19

Who: The U.K. university, in collaboration with the biopharmaceutical company AstraZeneca.

What: A viral vector vaccine.

Latest news: On January 12, the European Medicines Agency announced plans to review the Oxford-AstraZeneca vaccine and could issue conditional marketing authorization by the end of the month. The announcement comes amid a particularly severe surge of cases as a new and likely more contagious variant called B.1.1.7 rampages through the region. Early data suggest that the vaccine will effectively protect against the new variant prevalent throughout the U.K., and officials say more information about effectiveness against another variant racing through South Africa should be available soon.

Approval status: Approved for use in the United Kingdom, Argentina, India, and other countries.

Efficacy and safety: On December 8, The Lancet published an interim analysis of four of Oxford’s phase three trials. It showed the vaccine is safe and 70.4-percent effective in preventing COVID-19 after two doses, and 64.1-percent effective after one standard dose. In a subgroup analysis of the vaccine’s U.K. trial, the study also confirmed Oxford’s November 23 claim that the vaccine was 90-percent effective when given as a half dose followed by a full dose one month later. While further research is needed to confirm those results, the study authors note that the use of a lower dose would allow for wider distribution of the vaccine.

On November 18, preliminary results from Oxford’s phase two trials published in The Lancet, showed that the vaccine produced strong immune responses across all adult age groups, including older adults who are more vulnerable to the disease. Early results also revealed that the vaccine had triggered a strong immune response—including increased antibodies and responses from T cells—with only minor side effects such as fatigue and headache.

Distribution: Project members say their candidate can be stored in normal refrigeration, and they plan to seek an “emergency use listing” from the World Health Organization, which would set up their candidate for distribution in lower income countries. Oxford and AstraZeneca expect to produce up to three billion doses of the vaccine in 2021.

On December 30, the U.K. announced changes to its vaccine delivery plan: With COVID-19 infections spreading rapidly, the country will now prioritize delivering the first dose of either vaccine to as many at-risk people as possible, based on data provided to and released by health regulators. It will do so by delaying administration of the second dose of the AstraZeneca-Oxford drug; originally intended to be administered a few weeks after the first dose, patients will instead receive the second dose within 12 weeks. A similar rule was issued for the Pfizer-BioNTech vaccine—its two doses were previously split over three weeks—but regulators didn’t provide similar data to back the new regimen. Overall, the U.K. still recommends that recipients receive two doses of either vaccine for maximum benefit. Rollout of the AstraZeneca-Oxford vaccine will begin on January 4. Argentina announced a similar approval the same day as the U.K.

Clinical trials status: On December 11, AstraZeneca and Russia’s Gamaleya Institute announced they will work together to study the possibility of combining Oxford’s vaccine with Gamaleya’s Sputnik vaccine. Since both use the same adenovirus, researchers will investigate whether a combination of the two will improve efficacy. Clinical trials are expected to begin by the end of the month.

The AstraZeneca-Oxford vaccine’s phase three trial aims to recruit up to 50,000 volunteers in Brazil, the U.K., the United States, and South Africa. On September 8, AstraZeneca paused the trials for a safety review due to an adverse reaction in one participant in the U.K., which the company described as a “routine action.” After an investigation by independent regulators, the trials resumed in the U.K., Brazil, South Africa, and India in September and resumed in the U.S. a month later.

Name: NVX-CoV2373

Who: A biotechnology company based in Gaithersburg, Maryland.

What: A protein vaccine that involves a nanoparticle carrier to better aid delivery and uptake by cells.The vaccine is administered in two doses, 21 days apart.

Latest news: On December 28, Novavax announced the launch of its phase three study in the U.S. and Mexico, which will evaluate the safety and efficacy of its vaccine in up to 30,000 adults. The announcement comes a month after Novavax said it had completed enrollment in its phase three trial in the U.K., and that it expects to have interim data available in the first quarter of 2021.

Approval status: Not approved for use.

Efficacy and safety: On September 2, a study of the company’s phase one trial published in the New England Journal of Medicine found that the vaccine was safe and produced coronavirus antibodies at a higher level than is seen among those who have recovered from COVID-19. It also stimulated T cells, another arm of the human immune response.

Clinical trials status: On September 24, Novavax announced the launch of its phase three trial in the United Kingdom, which will evaluate the vaccine in up to 10,000 people, both with and without underlying conditions. Up to 400 participants will also be vaccinated against the seasonal flu as part of a sub-study that will help determine whether it is safe to give patients both vaccines at the same time. Trials in the U.S. and Mexico are now underway after several delays because of difficulties scaling up manufacturing, Reuters reports.

Name: BNT162b2

Who: One of the world’s largest pharmaceutical companies, based in New York, in collaboration with German biotech company BioNTech.

What: A nucleic-acid vaccine that requires two doses taken 21 days apart.

Latest news: On January 15, Pfizer announced that it will temporarily scale back the number of vaccine doses being delivered to Europe. The company says the disruption is the result of modifications being made to increase production capacity, according to CNBC. The disruption is expected to impact dose delivery through early February.

Approval status: On December 2, the U.K. became the first Western country to approve any COVID-19 vaccine when it authorized the Pfizer-BioNTech candidate—making the drug the first mRNA vaccine in history allowed for human use. The FDA granted emergency approval to this vaccine on December 11, a day after an advisory panel decided 17-4 that the benefits of the candidate outweigh the risks for anyone over the age of 16. The vaccine has also been granted emergency approval in Canada and conditional approval in the European Union.

Distribution: The first vaccinations in the U.S. were administered to health-care workers at a medical center in Queens, New York. The CDC has recommended that health-care personnel and long-term care residents receive the first doses, but the ultimate rollout will depend on state decision-making. The New York Times surveyed all 50 states to find out how many doses they expected by the end of the year; most Americans will likely have to wait until spring at the earliest to receive the shot. Pfizer and BioNTech have signed two nearly $2-billion contracts with the U.S. government to provide 200 million doses for free by July 31, 2021.

On December 17, the FDA said that extra doses found in vials of Pfizer’s COVID-19 vaccine can be used. Vials normally hold enough liquid for five shots, but after the company rolled out 6.4 million doses, pharmacists discovered that some vials contained enough for two extra shots. Being able to use them rather than discard them potentially expands the U.S. supply of the drug by 40 percent, Politico reports.

The British government said it would prioritize vaccinations for the most vulnerable populations, including nursing home residents, health-care workers, older adults, and those with underlying health conditions. For now, Pfizer and BioNTech have agreed to provide 40 million doses of the vaccine to the U.K. It will be delivered in stages throughout 2020 and 2021. The country expects to make several hundred thousand doses available by the end of this year.

Globally, Pfizer expects to be able to produce up to 50 million vaccine doses in 2020 and 1.3 billion doses by the end of 2021. However, questions have been raised over the vaccine’s storage, which requires ultra-cold freezers set at minus 70 degrees Celsius (minus 94 degrees Fahrenheit).

Efficacy and safety: The New England Journal of Medicine published the results of Pfizer’s phase three study, showing the vaccine was safe and 95-percent effective in protecting against COVID-19 in people 16 and older. The FDA has also published an analysis saying that the Pfizer vaccine is safe and offers strong protection against COVID-19 within 10 days of the first dose, regardless of the recipient’s race, weight, or age.

On December 15, a day after the U.S. launched its immunization campaign, a health-care worker in Alaska was hospitalized for a severe allergic reaction. According to the New York Times, the worker had no history of allergies, and the reaction subsided after she was treated with epinephrine. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, told CNBC that some adverse reactions are expected when a vaccine is distributed to a wider population.

Regulators in the United Kingdom are also investigating two allergic reactions that occurred as the country began its mass inoculation campaign earlier this month to people over the age of 16. Both people had a history of serious allergies, and both have since recovered, the AP reports. As a precautionary measure, U.K. officials have warned people with a history of serious allergic reactions to wait to get Pfizer’s COVID-19 vaccine.

The company is also testing how well its vaccine works against the new variant of the virus that’s been found in the U.K.

Clinical trials status: On November 18, Pfizer and BioNTech announced the conclusion of their phase three trials. The companies stated that they’ve met their primary goals: The analysis found the candidate to be 95 percent effective in preventing mild cases of COVID-19—and 94 percent effective in adults over 65 years old—with no serious safety concerns. The trials launched in July, enrolling a diverse population in areas with significant SARS-CoV-2 transmission. Pfizer has expanded the trial to include 44,000 people across multiple countries. Preliminary results of phase one/two data showed the vaccine produces antibodies and T-cell responses specific to the SARS-CoV-2 protein.

Name: Sputnik V

Who: A Russian research institution, in partnership with the state-run Russian Direct Investment Fund.

What: A viral vector vaccine that uses two strains of adenovirus and requires a second injection after 21 days to boost the immune response.

Latest news: Paraguay’s health officials approved Gamaleya’s Sputnik V vaccine on January 15, according to Russia’s sovereign wealth fund, following Venezuela’s move to issue emergency use authorization for the vaccine on January 13.

On December 11, the Gamaleya Institute and biopharmaceutical company AstraZeneca announced they will work together to study the possibility of combining Sputnik V with the candidate that AstraZeneca has developed with the University of Oxford. Since both candidates use the same adenovirus, researchers will investigate whether combining them will improve efficacy. Clinical trials are expected to begin by the end of the month.

Approval status: In August, Russia cleared the Sputnik V vaccine for widespread use and claimed it as the first registered COVID-19 vaccine on the market—before the vaccine’s phase three trials had begun and despite the lack of published evidence at the time. It has since been approved in Belarus, Argentina, Venezuela, and other countries.

Efficacy and safety: On November 11—two days after Pfizer’s announcement of its interim results—Gamaleya reported that an interim analysis of its phase three trial found 92 percent efficacy of the Sputnik vaccine. The report was only based on 20 cases, however, which experts say is too few to be convincing. In September, a study of the institute’s phase one/two trials published in the Lancet showed the vaccine produced antibodies and a reaction from T cells.

On December 14, Gamaleya announced that final results from its phase three trials pointed to an efficacy of 91.4 percent, based on more than 22,000 trial participants. Reuters reports that Gamaleya intends to publish the results in an international medical journal.

Name: JNJ-78436735

Who: One of the world’s largest multinational corporations, based in New Jersey, specializing in healthcare and pharmaceutical products.

What: An vector vaccine.

Latest news: On January 13, the New England Journal of Medicine published the results of an 805-participant phase two trial of Johnson & Johnson’s vaccine, which found promising evidence that the vaccine is safe and effective. But production of the vaccine is lagging. While the company pledged 12 million doses by the end of February and 100 million by the end of June, the company is likely at least two months behind schedule, according to the New York Times. On November 15, Johnson & Johnson launched a second phase three trial to study the safety and efficacy of a two-dose regimen of its vaccine candidate in up to 30,000 volunteers worldwide. The study intends to assess whether a second dose of the vaccine will offer longer protection.

Approval status: Not approved for use.

Efficacy and safety: On October 12, Johnson & Johnson announced that it paused phase three trials for an independent safety review due to an unexplained illness in a participant. The company didn’t provide any details, in part to protect the patient’s privacy, but said that illnesses and accidents are expected in large clinical studies. What’s more, study pauses are routine for clinical trials and aren’t typically reported. On October 23, the company announced it would resume trials.

In July, a study published in Nature showed that the vaccine elicited neutralizing antibodies in monkeys and provided “complete or near-complete” protection with just one dose. The phase two results reported in the New England Journal of Medicine found that among participants who received a single dose, 90 percent had antibodies 29 days later, and all recipients did 57 days later. Participants who received a second dose saw increased antibody levels.

Clinical trials status: On September 23, Johnson & Johnson announced the launch of its phase three “ENSEMBLE” trial to evaluate the safety of the vaccine—and how well it works—among up to 60,000 adults from a variety of countries. The trial will include “significant representation” from older populations and those with underlying conditions that make them more susceptible to COVID-19. The company announced on December 17 that the trial is fully enrolled with 45,000 participants; it expects to have interim data available by the end of January.

Name: Bacillus Calmette-Guerin BRACE trial

Who: The largest child health research institute in Australia, in collaboration with the University of Melbourne.

What: For nearly a hundred years, the Bacillus Calmette-Guerin (BCG) vaccine has been used to prevent tuberculosis by exposing patients to a small dose of live bacteria. Evidence has emerged over the years that this vaccine may boost the immune system and help the body fight off other diseases as well.

Latest news: On November 10, a U.S. study published in the Journal of Clinical Investigation found that among 6,201 healthcare workers in Los Angeles, those who had previously received the BCG vaccine reported symptoms of COVID-19 less often than those who hadn’t, a finding that study authors say strengthens the case for further research. In October, the U.K. launched a study of the BCG vaccine that is part of the Australian-led trials. The study is seeking to recruit 1,000 frontline health-care workers to test the vaccine’s effectiveness against COVID-19.

Clinical trials status: In April, researchers from the Murdoch Children’s Research Institute began a series of randomized controlled trials that will test whether BCG might work on the coronavirus as well. They aim to recruit 10,000 healthcare workers in the study. In an April 2020 scientific brief, the World Health Organization found that there is no current evidence that the BCG vaccine protects people against infection with the coronavirus.

Approval status: Not approved for use.

Name: Ad5-nCoV

Who: A Chinese biopharmaceutical company.

What: A viral vector vaccine.

Latest news: A Russian pharmaceutical company Petrovax announced that more than 90 percent of participants in Russian trials of Ad5-nCoV had high levels of antibodies, but few additional details are currently available. Indonesia has ordered 20 million doses of CanSino’s vaccine; Mexico signed an agreement to buy 35 million doses.

Approval status: Though the company was still technically in phase two of its trial, on June 25, CanSino became the first company to receive limited approval to use its vaccine in people. The Chinese government has approved the vaccine for military use only, for a period of one year.

Efficacy and safety: Preliminary results from phase two trials, published in The Lancet, have shown that the vaccine produces “significant immune responses in the majority of recipients after a single immunisation.” There were no serious adverse reactions documented.

Clinical trials status: On December 21, CanSino announced that it has recruited more than 20,000 participants for its phase three trials in Pakistan, Russia, Mexico, and Chile. On August 15, Russian biopharmaceutical company Petrovax announced it had launched the first phase three clinical trial of Ad5-nCoV.

Name: EpiVacCorona

Who: A Russian biotechnology institute.

What: A protein vaccine, namely it uses small fragments of viral antigens called peptides to produce an immune response.

Latest news: On January 13, Russian state news agency TASS reported that of the more than 2,000 volunteers who had received both doses of EpiVacCorona’s two-dose regimen, none reported adverse reactions from the vaccine. In November, Russia launched mass trials of its EpiVacCorona vaccine; the trials will inoculate 150 people over the age of 60 and 3,000 volunteers over the age of 18.

Approval status: On October 14, Russia granted regulatory approval to EpiVacCorona even though the vaccine candidate has not published any results and has not entered phase three of its clinical trials. It is the second vaccine candidate that Russia has approved for use despite a lack of published evidence about its safety and efficacy.

Name: CVnCoV

Who: A German biopharmaceutical company in partnership with Bayer, a German multinational pharmaceutical company.

What: An mRNA vaccine that’s administered in two doses taken 28 days apart.

Latest news: On January 11, CureVac announced that preliminary results show its vaccine prompted robust antibody and T-cell responses in rhesus macaques. The data have not yet been peer-reviewed.

Approval status: Not approved for use.

Clinical trials status: On December 14, CureVac announced it had begun enrolling participants in a phase 2b/3 study to assess its vaccine’s safety and efficacy in more than 35,000 participants in Europe and Latin America. One week later, the company launched a separate phase three trial in healthcare workers in Mainz, Germany.

Name: ZyCoV-D

Who: An Indian pharmaceutical company.

What: A DNA-based vaccine that is delivered by a skin patch.

Latest news: On January 3, Zydus Cadila announced it had received approval from Indian regulators to launch a phase three trial testing the safety and efficacy of its vaccine in about 30,000 volunteers.

Approval status: Not approved for use.

Safety and efficacy: In December, Zydus Cadila said that a combined phase one/two study of its vaccine showed it was safe and prompted an immunogenic response, but the company did not share any data.

Name: ZF2001

Who: A Chinese biopharmaceutical company, in partnership with the Institute of Microbiology at the Chinese Academy of Sciences.

What: A subunit vaccine that uses pieces of protein from a pathogen to trigger an immune response.

Latest news: In November, Chinese health officials announced the launch of phase three trials for the Anhui Zhifei vaccine. The trials—which will recruit 29,000 volunteers aged 18 or older—are expected to be conducted in China, Indonesia, Pakistan, and Ecuador.

Approval status: Not approved for use.

Name: QazCovid-in

Who: A research institute in Kazakhstan.

What: An inactivated vaccine.

Latest news: On January 14, Kazakh health officials granted a nine-month temporary registration to the QazCovid-In vaccine, despite a lack of data from its ongoing phase three trials. Prime Minister Askar Mamin has previously said he expects mass vaccination to begin in March 2021.

Approval status: Granted temporary registration in Kazakhstan.

Clinical trials status: In December, the institute announced that the Kazakh Ministry of Health approved the launch of phase three trials, which will assess the vaccine’s safety and efficacy in 3,000 volunteers.

Name: Unknown

Who: A Chinese research institute.

What: An inactivated vaccine that requires two doses taken 14 days apart.

Latest news: In December, researchers launched phase three clinical trials to test the efficacy and safety of the vaccine in 34,020 participants in Malaysia and Brazil.

Safety and efficacy: Preliminary results of the vaccine’s phase one trial showed that it prompted an immune response with no serious adverse incidents.

Editor's note: This story was originally published on July 31. It is regularly updated as developments occur.