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
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 including all the big shots like US, Russia, UK even India are participating in this race to bring a vaccine.
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, reports National Geography.
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. But even after the approval, things can go south without a plan of proper production and distribution. All the vaccine producers are in trial with their vaccines keeping one thing in mind - "urgency".
The US Centers for Disease Control and Prevention (CDC) has announced that they will start distributing the potential vaccine from November 1; on the other hand Oxford University's research lead is hoping to bring the vaccine by Christmas.
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—
University of Oxford collaboration with AstraZeneca (UK)
Name: ChAdOx1 nCoV-19
Oxford's candidate is what's known as a viral vector vaccine, essentially a "Trojan horse" presented to the immune system. Preliminary results from this candidate's first two clinical trial phases 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. It is in phase three of clinical trials, aiming to recruit up to 50,000 volunteers in Brazil, the United Kingdom, 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. The details remain unclear, though the company has described the pause 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 US a month later.
Pfizer (USA) in collaboration with BioNTech (Germany)
Pfizer and BioNTech are also developing an mRNA vaccine based on the German company's earlier efforts to use the technology in experimental cancer vaccines. Pfizer has signed a nearly $2 billion contract with the US government to provide 100 million doses by December 2020—an agreement that goes into effect when and if the drug is approved and delivered.
On July 27, Pfizer and BioNTech launched a trial that combines phase two and three by enrolling a diverse population in areas with significant SARS-CoV-2 transmission. It has expanded the trial to include 44,000 people across multiple countries. The project is aiming to seek regulatory review before the end of the year—and hopes to supply 1.3 billion doses by the end of 2021.
Moderna Therapeutics in collaboration with National Institutes of Health (USA)
On July 27, Moderna announced it had started the third phase of its clinical trials, even as it continues to monitor phase two results. Preliminary findings from phase one have shown that healthy subjects—including elderly patients—produced coronavirus antibodies and a reaction from T cells.
Phase three will test the vaccine in 30,000 US participants; Moderna says it is 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.
Sinovac (China) in collaboration with Butantan (Brazil)
CoronaVac is an inactivated vaccine that uses a non-infectious version of the coronavirus to provoke an immune response.
On July 3, Brazil's regulatory agency granted this vaccine candidate approval to move ahead to phase three, as it continues to monitor the results of the phase two clinical trials.
Preliminary results in macaque monkeys, published in Science, revealed that the vaccine produced antibodies that neutralized 10 strains of SARS-CoV-2. Sinovac has also released preprint results of its phase two human trial that likewise showed the vaccine produced antibodies with no severe adverse reactions.
Phase three will recruit nearly 9,000 healthcare professionals in Brazil. Sinovac will also conduct phase three trials in Indonesia and Bangladesh.
Bharat Biotech in collaboration with Indian Council of Medical Research and the National Institute of Virology (India)
COVAXIN uses an inactivated, or non-infectious, form of the coronavirus that can no longer cause disease but can still provoke an immune response. This vaccine 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.
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.
The Gamaleya National Center of Epidemiology and Microbiology (Russia)
Name: Sputnik V
Russia has not published any data from its clinical trials, but officials with the institute state that they have completed phases one and two. The researchers also claim the vaccine produced strong antibody and cellular immune responses.
Despite the lack of published evidence, Russia has cleared the Sputnik V vaccine for widespread use and claimed it as the first registered COVID-19 vaccine on the market. Russia reports that it will start phase three clinical trials on August 12; the World Health Organization, however, lists the Sputnik V vaccine as being in phase one of clinical trials.
Johnson & Johnson (USA)
Johnson & Johnson building the vaccine on the same technology that they 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.
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.