by Amy McKeever: These are the COVID-19 vaccine prospects that have made it to phase three trials and beyond…
More than 150 coronavirus vaccines are in development across the world—and hopes are high to bring one to market in record time to ease the global crisis. Several efforts are underway to help make that possible, including the U.S. government’s Operation Warp Speed initiative, which has pledged $10 billion and aims to develop and deliver 300 million doses of a safe, effective coronavirus vaccine by January 2021. 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.
It can typically take 10 to 15 years to bring a vaccine to market; the fastest-ever—the vaccine for mumps—required four years in the 1960s. Vaccines go through a three-stage clinical trial process before they are sent to regulatory agencies for approval—which can be a lengthy process itself.
Even after a vaccine is approved, 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. Many vaccines also stay in what’s called phase four, a perpetual stage of regular study. (Here’s how we’ll know when a COVID-19 vaccine is ready.)
Given the urgent need, some vaccine developers are compressing the clinical process for SARS-CoV-2 by running trial phases simultaneously. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, has stated that independent Data and Safety Monitoring Boards can end trials early if their interim results are overwhelmingly positive or negative. Meanwhile, in response to the Trump Administration’s attempts to pressure the U.S. Food and Drug Administration to quickly approve a vaccine, several states—including California, New York, and West Virginia—have announced plans to independently review the data for any candidate the FDA approves.
On December 11, the FDA granted its first emergency use authorization for a COVID-19 vaccine—which allows the use of an unapproved medical product in a life-threatening situation—to the Pfizer-BioNTech candidate. Yet CDC director Robert Redfield, vaccine developers, and the FDA have said it’s unlikely a vaccine will be widely available until the middle of 2021.
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, some 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 coronavirus proteins into a different virus that is unlikely to cause disease or even incapable of it. Finally, some vaccines under development rely on deploying pieces of the coronavirus’s genetic material, so our cells can temporarily make the coronavirus proteins needed to stimulate our immune systems. (Find out more about vaccines and how they work.)
Though it’s too soon to say which candidates will ultimately be successful, here’s a look at the prospects that have reached phase three and beyond—including a quick primer on how they work and where they stand.
Who: One of the world’s largest pharmaceutical companies, based in New York, in collaboration with German biotech company BioNTech.
What: This vaccine candidate relies on injecting snippets of a virus’s genetic material, in this case messenger RNA (mRNA), into human cells. It spurs the production of viral proteins that mimic the coronavirus, training the immune system to recognize its presence. This vaccine requires two doses taken 21 days apart.
Status: On December 11, the FDA granted emergency approval to Pfizer’s COVID-19 vaccine, a day after an advisory panel voted 17 to 4 that the benefits of the candidate outweigh the risks for anyone over the age of 16. An initial shipment of about 2.9 million doses will be shipped across the U.S. over the next week. The decision came the morning after 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. The CDC recommended on December 3 that health-care personnel and long-term care residents receive the first doses, but the ultimate rollout will depend on state decision-making.
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). The initial 6.4 million doses of Pfizer’s vaccine are expected to leave warehouses within 24 hours of the FDA’s announcement. Pfizer has signed a nearly $2 billion contract with the U.S. government to provide 100 million doses for free, though the New York Times reports that only half its supply will go to the U.S. this year. The company has also launched a vaccine delivery pilot program with four U.S. states—Rhode Island, Texas, New Mexico, and Tennessee—to prepare for deployment of the vaccine in the United States.
The FDA’s announcement comes days after the United Kingdom began to roll out Pfizer’s vaccine to people over the age of 16. The U.K. was the first Western country to approve any COVID-19 vaccine candidate—and the drug also became the first mRNA vaccine in history allowed for human use. On December 9, however, U.K. regulators warned people with a history of serious allergic reactions to wait to get Pfizer’s COVID-19 vaccine. They are investigating two adverse reactions that occurred as the country began its mass inoculation campaign. Authorities did not specify what those reactions were but noted that the investigation is a precautionary measure.
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.
Canadian health officials have also granted emergency approval to Pfizer’s COVID-19 vaccine. The country expects to make several hundred thousand doses available by the end of this year.
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: ChAdOx1 nCoV-19
Who: The U.K. university, in collaboration with the biopharmaceutical company AstraZeneca.
What: Oxford’s candidate is what’s known as a viral vector vaccine, essentially a “Trojan horse” presented to the immune system. Oxford’s research team has transferred the SARS-CoV-2 spike protein—which helps the coronavirus invade cells—into a weakened version of an adenovirus, which typically causes the common cold. When this adenovirus is injected into humans, the hope is that the spike protein will trigger an immune response. AstraZeneca and Oxford plan to produce a billion doses of vaccine that they’ve agreed to sell at cost.
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 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.
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.
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 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.
The 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: Sputnik V
Who: A Russian research institution, in partnership with the state-run Russian Direct Investment Fund.
What: Gamaleya has developed a viral vector vaccine that also uses a weakened version of the common cold-causing adenovirus to introduce the SARS-CoV-2 spike protein to the body. This vaccine uses two strains of adenovirus, and it requires a second injection after 21 days to boost the immune response. 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.
Status: On December 11, the Gamaleya Institute and biopharmaceutical company AstraZeneca announced they will work together to study the possibility of combining Gamaleya’s Sputnik vaccine with the candidate that AstraZeneca has developed with the University of Oxford. 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 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.
Who: China’s state-run pharmaceutical company, in collaboration with the Wuhan Institute of Biological Products.
What: Sinopharm is using an inactivated SARS-CoV-2 vaccine, a non-infectious form of the coronavirus that can no longer cause disease but can still provoke an immune response. Preliminary findings from two randomized trials, published in JAMA, 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.
Status: On December 9, the United Arab Emirates approved Sinopharm’s vaccine for general use, saying 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 claimed the vaccine is 100-percent effective in preventing moderate and severe cases of the disease, however no data has been released from the study.
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. 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.
Who: A Massachusetts-based biotech company, in collaboration with the National Institutes of Health.
What: This vaccine candidate also relies on injecting snippets of mRNA into human cells to trigger an immune response. This vaccine requires two doses, four weeks apart. (Here’s how mRNA vaccines work.)
Status: On November 30, Moderna said it was filing for emergency authorization from the FDA based on data from its phase three study that shows the vaccine is 94.1-percent effective in preventing mild cases of COVID-19, the primary target for the trial. The company also claimed that its vaccine is 100-percent effective at preventing severe cases of the disease, though this secondary analysis remains ongoing. Moderna says the FDA plans to review its application on December 17. If approved, it will begin to ship the vaccine for distribution shortly after.
The announcement comes weeks after Moderna announced that an interim analysis of its phase three study shows the vaccine is 94.5-percent effective in preventing COVID-19, including severe cases of the disease. Moderna has not yet presented underlying data on how the vaccine produced these effects. In a separate announcement, the company also said its vaccine can be safely stored on ice or in a normal refrigerator for 30 days.
Moderna 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; Moderna expects to have 20 million doses ready to ship in the U.S. by the end of the year and says it remains on track to deliver at least 500 million doses per year beginning in 2021, thanks in part to the deal it has struck with Swiss manufacturer Lonza that will allow it to manufacture up to one billion doses a year. In September, however, Moderna’s chief executive Stéphane Bancel told the New York Times that it was unlikely the vaccine would be widely available in the first half of 2021.
Who: A Chinese biopharmaceutical company, in collaboration with Brazilian research center Butantan.
What: CoronaVac is an inactivated vaccine that uses a non-infectious version of the coronavirus to provoke an immune response.
Status: 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. 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 and Bangladesh. Preliminary results in macaque monkeys, published in Science, revealed that the vaccine produced antibodies that neutralized 10 strains of SARS-CoV-2.
Who: An Indian biotechnology company, in collaboration with the Indian Council of Medical Research and the National Institute of Virology.
What: COVAXIN also uses an inactivated vaccine, which requires two doses that are administered 14 days apart. 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.
Status: On October 23, Bharat Biotech announced it has received approval to start phase three trials in 26,000 participants at more than 25 centers across India.
Who: A biotechnology company based in Gaithersburg, Maryland.
What: Novavax has bioengineered the coronavirus’s spike proteins, the parts that help the virus invade cells but cannot replicate or cause COVID-19. Its vaccine candidate combines those proteins into a knucklebone-shaped nanoparticle. This can be injected along with its proprietary Matrix-M adjuvant—a compound that stimulates immune cells—to elicit an immune response. The vaccine is administered in two doses, 21 days apart. 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.
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.
Who: One of the world’s largest multinational corporations, based in New Jersey, that specializes in healthcare and pharmaceutical products.
What: Johnson & Johnson is developing an adenovector vaccine, which introduces a piece of DNA from SARS-CoV-2 into the common cold-causing adenovirus that has been genetically changed so that it can’t replicate in the body. This vaccine builds on the technology Johnson & Johnson used to develop an Ebola vaccine as well as vaccine candidates for Zika and HIV. 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.
Status: On September 23, Johnson & Johnson announced the launch of a 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. On October 12, Johnson & Johnson announced that it has paused these 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 will resume trials.
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. Researchers are investigating whether these benefits may also extend to SARS-CoV-2, and this trial has reached phase three in Australia. Though as of April 12, the World Health Organization says there is no evidence that the BCG vaccine protects people against infection with the coronavirus.
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.