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The story so far: On April 23, the University of Oxford launched a phase 1 human clinical trial of its vaccine, ChAdOx1 nCoV-19, against the new coronavirus, SARS-CoV-2. A single dose of the candidate vaccine will be administered to 1,112 healthy volunteers to study the safety, the ability to elicit an immune response, and the efficacy of the vaccine. The University of Oxford is optimistic about a positive result of the candidate vaccine and has planned to receive millions of doses of the vaccine before the end of the year, even while awaiting the results of the final phase of the trial (phase 3). The candidate vaccine was developed by the University Jenner Institute, which began human trials on April 23 in conjunction with the University’s Oxford Vaccine Group.
How was the vaccine being tested built?
The vaccine, ChAdOx1 nCoV-19, uses the common cold virus (adenovirus) that causes infections in chimpanzees. The adenovirus has been genetically altered so that it does not grow once injected. The construct carries the genetic material of the new coronavirus that produces the spike protein. The spike protein is found on the surface of the virus and plays a crucial role in binding to specific human receptors found on cell surfaces and entering cells.
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By introducing the genetic material of the spike protein, the candidate vaccine will help the body recognize it and produce antibodies against the spike protein. The antibodies produced will help generate an immune response and prevent the virus from entering human cells and causing an infection.
The University of Oxford has used vaccines made with the adenovirus construct for more than 320 people and has found it to be safe and well tolerated. It causes transient side effects, such as fever, headache, or arm pain, but is otherwise safe.
Has it been tested on animals?
The adenovirus construct has been used by researchers at the University of Oxford to assess the safety of both the 2002 Severe Acute Respiratory Syndrome (SARS) and the Middle East Respiratory Syndrome (MERS). Once the safety of the vaccine was demonstrated MERS In a UK trial, a trial was started in December last year in Saudi Arabia, where MERS outbreaks occur frequently.
The safety of the candidate vaccine was previously tested on six rhesus macaque monkeys.
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A single dose protected all six animals for almost a month, even when exposed to high levels of the virus, increasing the researchers’ confidence.
What is the clinical trial process?
As many as 1,112 healthy volunteers from Oxford, Southampton, London and Bristol have been recruited for the Phase 1 trial. Volunteers, male and female, ages 18-55, are being recruited for the trial. A single dose of the candidate vaccine will be administered to the volunteers. Participants will be randomly assigned to receive the candidate vaccine (ChAdOx1 nCoV-19) or a “control”, the MenACWY vaccine, for comparison.
The University of Oxford is using the MenACWY vaccine, which protects against four strains of meningococcal bacteria, instead of a saline control. Participants will not know if they received a candidate vaccine or not. The university researchers will also test two doses of the candidate vaccine four weeks apart in a small group of 10 volunteers to assess the dose and the immune response.
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For the control group, why is a vaccine for meningococcal bacteria used and not saline?
The MenACWY vaccine is a licensed vaccine that has been routinely administered to adolescents in the UK since 2015. The MenACWY vaccine is being used as an “active control” vaccine to help understand participants’ response to ChAdOx1 nCoV-19. The reason for using this vaccine, rather than a saline control, is because the researchers hope to see some minor side effects of the ChAdOx1 nCoV-19 vaccine, such as arm pain, headache, and fever. Saline does not cause any of these side effects. If participants received only this vaccine or a saline control and developed side effects, they would know that they had received the new vaccine. It is critical to the study, says the University of Oxford, that participants remain blinded to whether or not they have received the vaccine, “because, if they knew, this could affect their health behavior in the community after vaccination and can lead to bias in the study results. “
While all participants will be told how to reduce the risk of infection, participants who receive both vaccines do need to be exposed to the virus and some to become infected. Only then will it be possible to understand whether or not the vaccinated group remained protected compared to the control arm. For this purpose, keeping participants in the dark about the vaccine received makes the trial robust.
What is the timeline for the trial?
The Phase 1 trial is expected to complete in late May if transmission remains high in the community. The phase 2 trial can be completed in August-September. According to Suresh Jadhav, Executive Director of the India Whey Institute Pvt. Ltd., phase 2 and phase 3 trials can be combined if the results of the phase 1 trial are encouraging.
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When will the Pune Whey Institute start manufacturing the vaccine?
According to Mr. Jadhav, the company will start manufacturing the vaccine as soon as the Phase 3 trial or the Phase 2 / Phase 3 combination trial begins. If the last two stages of the trial are combined, it would begin manufacturing the vaccine. Vaccine in late June and would be ready with millions of doses by the end of the year The company hopes to manufacture between 60 and 70 million doses of vaccines by the end of the year. He says, “Since we will start manufacturing when the last phase of the trial begins, we will have millions of doses of vaccines ready by the time the trial ends.”
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How much will it cost?
In a tweet on April 30, the University of Oxford said it is partnering with AstraZeneca to manufacture and distribute the vaccine as quickly as possible. He said the vaccine will be available “non-profit for the duration of the coronavirus pandemic.”
