While Russia and China may have stolen a march in the race to develop a Covid-19 shot, granting regulatory approval to vaccine candidates even before Phase III human trials, all eyes are on the other leading vaccine candidates by Pfizer, Oxford University-AstraZeneca, and Moderna. All three are currently undergoing late-stage trials and it has become evident that a vaccine would be made available this year itself. On Tuesday, Russia released the first batch of its Sputnik V Covid-19 vaccine for public use.
According to the World Health Organisation, about 175 vaccine candidates are in pre-clinical or clinical trials at present. About 33 of them are in the clinical trials phase. Eight contenders are in final stages, phase-III of human trials. At least eight candidate vaccines are being developed in India of which two are in phase II trial phase.
Here is a status check of Covid-19 vaccine frontrunners
Oxford University-AstraZeneca Covid-19 vaccine
Being viewed as a front-runner in the global race to deliver an effective vaccine to combat Covid-19, the ChAdOx1 nCoV-19 vaccine is now undergoing Phase III clinical trials in Britain, Brazil, South Africa and India. The vaccine is made from a weakened version of a common cold virus, called an adenovirus, that infects chimpanzees.
💉 The United States has become the latest country where Oxford University and AstraZeneca has started phase-3 clinical trials. Trials are soon likely to start in Japan and Russia as well. In the US trials, about 30,000 participants are likely to be enrolled. Globally, the Oxford vaccine trials are expected to involve 50,000 participants.
The origins of the Oxford vaccine with Professor Adrian Hill; standing next to the legendary Edward Jenner statue, here at @UniofOxford. Proud and excited for the next few months and looking forward to the vaccine. pic.twitter.com/rRJVBWGV7N
— Adar Poonawalla (@adarpoonawalla) September 7, 2020
💉 In India, the vaccine, known as Covishield, is undergoing combined phase-2 and phase-3 trials, which will cover 1,600 participants in India across 17 sites. Trials are being handled by Serum Institute of India and will look at safety and efficacy of the vaccine.
💉 Australian Prime Minister Scott Morrison has said the country would receive the first batches of Oxford’s potential Covid-19 vaccine in January. “Australia will in January and February 2021 receive 3.8 million doses of the vaccine,” he said.
Pfizer-BioNTech Covid-19 vaccine
The BNT162b2 vaccine being developed by Pfizer, along with German biotechnology company BioNTech, is also undergoing Phase-3 trials. The vaccine uses messenger RNA to prompt the immune system to recognise the coronavirus. Pfizer has recently said that early data from its Phase-3 trials would be available by October.
💉 According to an NYT report, Pfizer has said it would seek emergency use authorisation for its vaccine as early as October from the US Food and Drug Administration, once it was established that the vaccine was indeed effective. However, CEO of Pfizer, Albert Bourla, has maintained that the firm won’t cut corners. “If we do not have results from the Phase 3 study, we will not submit for approval, nor for authorisation,” he said.
💉 Preliminary results from Phase I/II clinical trials released last month showed the vaccine elicited a robust immune response in participants, which increased with dose level and with a second dose.
💉 Pfizer has already manufactured hundreds of thousands of doses of the vaccine candidate, including at a plant in Belgium.
Moderna Covid-19 vaccine
The mRNA-1273 vaccine developed by US biotech company Moderna is undergoing Phase III trials where scientists will evaluate a 100µg dose of the vaccine candidate in around 30,000 participants in the US. Moderna Inc is planning to price its coronavirus vaccine at $50 to $60 per course.
💉 Last month, Moderna said its vaccine generated promising immune response in elderly patients in early stage clinical trials, indicating its potential efficacy across age groups. Data showed that antibody levels in older adults were two to three times higher than those found in patients who had recovered from Covid-19.
💉 At present, Phase III trials are being conducted on 13,000 participants, of which 18% are Black, Latino, Native American or Alaska Native groups, reported Reuters. The company plans to complete enrollment for its late-stage trial in September.
💉 Last month, President Donald Trump announced the US government would purchase 100 million doses of Moderna’s vaccine in a deal worth $1.53 billion. It has already received nearly $1 billion under the Operation Warp Speed program.
Gamaleya Institute, Russia Covid-19 vaccine
The Sputnik V vaccine developed by Moscow’s Gamaleya Institute is the first in the world to be authorised for general use. It was approved by the Russian government on August 11, without Phase 3 trials, triggering global criticism. The vaccine uses two adenoviruses to inject the genetic material of the novel coronavirus into humans in order to trigger an immune response.
💉 The first batch of the Sputnik V vaccine against Covid-19 has been released for public use and regional supplies were expected soon, the Russian health ministry said in a statement. “The first batch of the ‘Gam-COVID-Vac’ (Sputnik V) vaccine for the prevention of the new coronavirus infection has passed the necessary quality tests in the laboratories of Roszdravnadzor (medical device regulator) and has been released into civil circulation,” the ministry said in a statement.
💉 According to results of phase-1 and phase-2 clinical trials published in The Lancet, the Russian vaccine has been found to be safe and also triggered a “strong” immune response. Trials on 76 people show that the vaccine induced antibody responses in all participants within 21 days.
💉 Phase 3 trials will start soon in many countries, including Saudi Arabia, UAE, Brazil, and the Philippines, with the developers planning to enroll 40,000 volunteers.
💉 With India showing interest in the Sputnik V vaccine, the Gamaleya Institute has submitted “comprehensive data” on the vaccine’s safety and efficacy to the authorities. Separate Phase 3 clinical trials may also be held in India after necessary approvals from regulators.
Bharat Biotech Covaxin
India’s first indigenous Covid-19 vaccine, Bharat Biotech’s Covaxin, is set to begin Phase-II human trials. An “inactivated” vaccine, Covaxin works by injecting doses of the virus that have been killed to prompt the body to build antibodies against it without the virus posing a threat.
💉 Bharat Biotech will conduct Phase II trials on 380 participants. In the first phase of the Covaxin trial, around 375 participants were studied across 12 sites.
💉 Dr Savita Verma at Post-Graduate Institute (PGI) of Medical Sciences, Rohtak, has said that no adverse events were reported in subjects dosed with Covaxin.
The different phases of vaccine testing:
Pre-clinical tests: In this stage, scientists test the vaccine in the laboratory using cells or animals.
Phase I trials: This is the first step where the experimental vaccine is given to humans and examines the safety, dosage, and possible side effects. This stage typically takes around two months and involves small numbers of participants, usually 20 to 100 healthy volunteers.
Phase II trials: In this stage, several hundred individuals are enrolled for testing and they are split into groups age-wise such as children and elderly. This stage studies the candidate vaccine’s immunogenicity, proposed doses, schedule of immunisations and method of delivery.
Phase III trials: In this stage, the candidate vaccine is tested in hundreds to thousands of volunteers for its ability to prevent infection in humans in real-life situations (outside of laboratory conditions). During a pandemic, a vaccine may receive emergency use authorisation before a formal green signal.
Approval: After Phase III trials, the developer submits a license application to the regulatory authority in their respective country. The regulator then inspects the factory where the vaccine will be made and approves its labeling.
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