The candidates, like all vaccines, are essentially aimed at asking the immune system to mount a defense, which is sometimes stronger than what would be provided by a natural infection and has less consequences on health.
To do this, some vaccines use the whole of the coronavirus, but in the killed or weakened state. Others only use part of the virus – whether it’s a protein or a fragment. Some transfer the proteins from the coronavirus into a different virus which is unlikely or even incapable of causing disease. Finally, some vaccines in development rely on deploying pieces of genetic material from the coronavirus so that our cells can temporarily make the coronavirus proteins needed to boost our immune system. (Here’s what vaccines are and how they work.)
It can usually take 10 to 15 years to get a vaccine to market; fastest ever – the mumps vaccine – took four years in the 1960s. Vaccines go through a multi-step clinical trial process, which begins with verifying their safety and whether they trigger an immune response in a person. small group of healthy humans. The second phase expands the testing pool to include groups of people who may or may have the disease, in order to assess the effectiveness of the vaccine. The third phase expands the pool to thousands to ensure that the vaccine is safe and effective for a wider range of people, as the immune response may vary depending on age, ethnicity or underlying health problems. It is then submitted to regulatory agencies for approval – which can be a long process in itself.
Even after a vaccine is approved, it faces potential hurdles in manufacturing and distribution, from increasing production to meet demand, to choosing which populations should get it first – and At what price. Many vaccines also remain in what is called phase four, a lifelong stage of regular study. (Here’s how we’ll know when a COVID-19 vaccine is ready.) But vaccine developers are trying to compress that process for SARS-CoV-2 by simultaneously running phases of clinical trials, and the U.S. Food and Drug Administration has promised to fast – follow the approval process.
While it’s too early to say which candidates will ultimately be successful, here’s a look at the prospects for vaccines that have reached phase three and beyond, including a brief look at how they work and where they stand.
WHO: A Massachusetts-based biotechnology company in conjunction with the National Institutes of Health.
What: This vaccine candidate is based on the injection of extracts of genetic material from a virus, in this case mRNA, into human cells. They create viral proteins that mimic the coronavirus, causing the immune system to recognize its presence. This technology has never been approved for any disease. If successful, this would be the first mRNA vaccine approved for human use. (This is how mRNA vaccines work.)
Status: On July 27, Moderna announced that it had started the third phase of its clinical trials, even as it continued to monitor the results of phase two. Preliminary results from Phase 1 showed that healthy subjects produced anti-coronavirus antibodies and a T-cell response, another arm of the human immune response. The third phase will test the vaccine in 30,000 American participants. Moderna says it is on track to deliver at least 500 million doses per year from 2021, in part thanks to the deal with Swiss manufacturer Lonza that will allow it to manufacture up to one billion doses per year.
WHO: One of the largest pharmaceutical companies in the world, based in New York, in collaboration with the German biotechnology company BioNTech.
What: Pfizer and BioNTech are also developing an mRNA vaccine based on the German company’s earlier efforts to use this technology in experimental cancer vaccines. Pfizer has signed a nearly $ 2 billion contract with the U.S. government to deliver 100 million doses by December 2020 – an agreement that takes effect when and if the drug is approved and delivered.
Status: On July 27, Pfizer and BioNTech launched a trial that combines phases two and three by recruiting a diverse population in areas where the transmission of SARS-CoV-2 is high. He will examine the effect of the vaccine in 30,000 people in 39 US states and Brazil, Argentina and Germany. The project aims to seek regulatory review as early as October 2020 to meet the December deadline – and hopes to deliver 1.3 billion doses by the end of 2021. Preliminary results from phase one / two data show that the vaccine produces antibodies and T cell responses specific to the SARS-CoV-2 protein.
WHO: The British University, in collaboration with the biopharmaceutical company AstraZeneca.
What: The Oxford candidate is what is called a viral vector vaccine, essentially a “Trojan horse” presented to the immune system. The Oxford research team transferred the SARS-CoV-2 spike protein – which helps the coronavirus invade cells – into a weakened version of an adenovirus, which usually causes the common cold. When this adenovirus is injected into humans, it is hoped that the spike protein will trigger an immune response. AstraZeneca and Oxford plan to produce a billion doses of the vaccine that they have agreed to sell at cost.
Status: Preliminary results from the first two phases of this candidate’s clinical trials revealed that the vaccine elicited a strong immune response – including an increase in antibodies and T-cell responses – with only minor side effects such as fatigue and headache. of head. It has now entered phase three of the clinical trials, aiming to recruit up to 50,000 volunteers in Brazil, the United Kingdom, the United States and South Africa.
WHO: A Chinese biopharmaceutical company, in collaboration with the Brazilian research center Butantan.
What: CoronaVac is an inactivated vaccine, which means it uses a non-infectious version of the coronavirus. Although inactivated pathogens can no longer produce disease, they can still elicit an immune response, as with the annual influenza vaccine.
Status: On July 3, the Brazilian regulatory agency granted the vaccine candidate permission to move to phase three, while it continues to monitor the results of phase two clinical trials. Sinovac says early phases have so far shown that the vaccine produces an immune response without serious side effects. Preliminary results of previous tests of this candidate on macaque monkeys, published in Science, found that the vaccine produced antibodies that neutralized 10 strains of SARS-CoV-2. The third phase will recruit nearly 9,000 healthcare professionals in Brazil.
WHO: Chinese state-owned pharmaceutical company, together with the Wuhan Institute of Biologics.
What: Sinopharm is also using an inactivated SARS-CoV-2 vaccine which it hopes will reach the public by the end of 2020. Sinopharm reported that the first trials of its vaccine candidate have triggered a strong antibody response neutralizers in participants, without serious side effects.
Status: In mid-July, Sinopharm launched its phase three trial involving 15,000 volunteers – aged 18 to 60, with no serious underlying problems – in the United Arab Emirates. The company chose the UAE because it has a diverse population with around 200 different nationalities, making it an ideal testing ground.
Last name: BRACE trial by Bacillus Calmette-Guerin
WHO: Australia’s largest child health research institute, in collaboration with the University of Melbourne.
What: For nearly a hundred years, the Bacillus Calmette-Guérin (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 can boost the immune system and help the body fight off other diseases. Researchers are examining whether these benefits can extend to SARS-CoV-2 as well, and this trial has reached phase three in Australia. Although 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 at the Murdoch Children’s Research Institute launched a series of randomized controlled trials that will test whether BCG could work on the coronavirus as well. They aim to recruit 10,000 health workers in the study.
Last name: Ad5-nCoV
WHO: A Chinese biopharmaceutical company.
What: CanSino has also developed a viral vector vaccine, using a weakened version of the adenovirus as a vehicle to introduce the SARS-CoV-2 spike protein into the body. Preliminary results from phase two trials, published in The Lancet, showed that the vaccine produced “significant immune responses in the majority of recipients after a single vaccination”. No serious side effects have been documented.
Status: Although the company is 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 humans. The Chinese government has approved the vaccine for military use only, for a period of one year.