Oxford University has initiated a phase-1 human clinical trial of its vaccine against the novel coronavirus, SARS-CoV-2. A single dose of the candidate vaccine will be administered to 1,112 healthy volunteers to study the safety, ability to produce immune response and efficacy of the vaccine. Oxford University is optimistic of a positive outcome of the candidate vaccine and has planned to get millions of doses of the vaccine before the end of the year even as results of the final phase of the trial are awaited.
The proposed vaccine for corona virus by Oxford University 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 novel coronavirus that makes 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 the cells.
By introducing the genetic material of the spike protein, the candidate vaccine will help the body recognise it and make antibodies against the spike protein. The antibodies produced will help mount an immune response and prevent the virus from entering the human cells and causing an infection.
Oxford University has used vaccines made from the adenovirus construct to over 320 people and has found it to be safe and well tolerated. It does cause transient side effects such as fever, headache or a sore arm but is otherwise safe.
The safety of the candidate vaccine was earlier tested on six rhesus macaque monkeys. A single dose protected all the six animals for nearly a month even when exposed to high levels of the virus, boosting the confidence of the researchers.
Up to 1,112 healthy volunteers have been recruited for the phase-1 trial. Volunteers, both male and female between 18-55 years, are being recruited for the trial. A single dose of the candidate vaccine will be administered to volunteers. The university researchers will also be testing two doses of the candidate vaccine given four weeks apart on a small group of 10 volunteers to assess the dosage and immune response.
The phase-1 trial is expected to be completed by May-end if transmission remains high in the community. The phase-2 trial may be completed by August-September. In fact, phase-2 and phase-3 trials may get combined if the phase-1 trial results are encouraging.
Pune’s Serum Institute, a partner in the project, has said that the company will start manufacturing the vaccine the moment the phase-3 trial or the combined phase-2/phase-3 trial begins. If the last two stages of the trial are combined then it would start manufacturing the vaccine by June-end and be ready with millions of doses by the end of the year. The company is confident of manufacturing 60-70 million vaccine doses by the end of the year.