- Recruiting for Phases II, III begins
- Team prepares to assess vaccine efficiency
- Meningitis vaccine to be used as control
Scientists at the University of Oxford began recruiting candidates on Friday for Phases II and III of human clinical trials of their coronavirus vaccine.
A statement released by the group said the first phase of human trials had seen the participation of 1,000 healthy adult individuals. For Phase II trials, the university is seeking 10,260 candidates, including senior citizens between 56-70 years of age and children of ages 5-12. In Phase III, the vaccine will be tested on a larger population.
Sarah Gilbert, professor of vaccinology at the Jenner Institute and lead researcher, said the vaccine trial team "have been working hard on assessing the safety and immunogenicity of ChAdOx1 nCoV-19 [the name of the vaccine], and are preparing to assess vaccine efficacy".
"We have had a lot of interest already from people over the age of 55 years who were not eligible to take part in the Phase I study, and we will now be able to include older age groups to continue the vaccine assessment."
Professor Andrew Pollard, head of the Oxford Vaccine Group, said, "The clinical studies are progressing very well and we are now initiating studies to evaluate how well the vaccine induces immune responses in older adults, and to test whether it can provide protection in the wider population."
Participants in both upcoming phases will be randomised to receive one or two doses of either the coronavirus vaccine or a control vaccine: MenACWY, which is usually given to teenagers for protection against meningitis.
The participants won't know if they received the coronavirus vaccine or the control vaccine unless the trials are complete.
The researchers say it is critical for this study "that participants remain blinded to whether or not they have received the vaccine, as this could affect their health behaviour in the community following vaccination, and may lead to a bias in the results of the study."
UK-based biopharmaceuticals company AstraZeneca says it has entered into an agreement with the Oxford group to manufacture 400 million doses of the vaccine by September.
THE ROAD AHEAD
The trial will assess how well people across a broad range of ages could be protected from the SARS-CoV-2 coronavirus by the new vaccine.
Scientists expect to use this vaccine to make the human body recognise and develop an immune response that will help stop the coronavirus from entering human cells and prevent infection.
Some participants get an e-diary to record symptoms after receiving the vaccine.
A weekly survey will also be done to check any household exposure to the virus.
Follow-up testing for both the coronavirus and antibodies will be done.
The researchers will then compare the results of the two groups, but it's necessary for a small number of participants to develop Covid-19, the disease caused by the virus.
"How quickly we reach the numbers required will depend on the levels of virus transmission in the community. If transmission remains high, we may get enough data in a couple of months to see if the vaccine works. But if transmission levels drop, this could take up to six months." the researchers said.
For this purpose, those with a higher chance of being exposed to the virus -- such as health workers and other essential service providers -- are given priority in these trials.
The results, once available, will be reviewed by neutral experts as well has regulatory bodies before a commercial licence is granted.
If the trial fails, the researchers say, they will review progress and examine alternative approaches -- such as using different numbers of doses -- and could potentially stop the programme.