A team of Oxford scientists led by Trinity alum Professor Adrian Hill have made a significant breakthrough with ongoing work on a Covid-19 vaccine as a first round of human trials indicate that the vaccine is safe and produces a response.
Hill, a Ranelagh native medicine graduate from Trinity, is the director of Oxford’s Jenner Unit, which includes four other researchers.
The results of initial clinical trials of the vaccine have been released, with largely positive results. The trials involved over 1,000 participants, who were injected with a variation of the adenovirus (a common cold virus). This particular virus causes infections in chimpanzees but has been altered genetically so as to not affect humans.
Injection of this weakened adenovirus during trials resulted in the formation of Covid-19-fighting antibodies and white blood cells. In addition to this, participants did not experience any serious side effects as a result of the vaccine.
The production of virus-combatting antibodies does not guarantee that a vaccine will be completely effective. However, the existing results indicate that further testing of the vaccine should go ahead. Larger trials with participant numbers of around 30,000 are currently underway to give further clarity.
In March, the research group gave doses of the vaccine to six rhesus monkeys, with similar genetic make-up to human beings. At this stage, the results were promising as all six monkeys remained healthy after being consistently exposed to large numbers of affected monkeys for over 28 days. Though the new test results from human participants give a much clearer picture of the efficacy of the vaccine, these earlier results were also crucial.
Currently, the team from Oxford, which is partnered with Astra Zeneca pharmaceutical company for production, believes in providing the vaccine in two separate inoculations. According to Professor Hill, this is due to this method giving higher antibody titres (levels of antibodies in the blood) than a one-shot regimen.
The journey towards a vaccine for Covid-19 has been eagerly followed worldwide, as research teams across the globe have been working around the clock to develop a treatment for the virus. Early on, the Oxford-based research group gained attention.
There have been challenges along the way for the team, however. Firstly, there is the question of medical ethics in vaccine testing. Medical ethics generally prevent researchers from infecting human participants with diseases with serious or deadly consequences. Covid-19 fills those criteria, so researchers had to involve participants from Covid-19 hotspots who would likely come in contact with the virus during day to day life.
Then, as in all clinical trials, some participants were administered the actual vaccine and others were administered a placebo vaccine. Initially, the UK based group expressed concern that by the time they had reached the human trial phase of the vaccine testing, there would be insufficient hot spots in the UK and that trials would have to be carried out abroad.
Speaking to the Irish Times, Hill said: “We’re the only people in the country who want the number of new infections to stay up for another few weeks, so we can test our vaccine… We’ll have to chase the epidemic.”
However, due to fairly consistent levels of the virus in the country, this has not turned out to be an issue for the group thus far.
Another challenge that the team is currently facing is predicting the duration of antibody response shown in the human trials. This is different for all vaccines and cannot be estimated from other commonly-used vaccines. Ultimately, the researchers must play the waiting game and see when participants experience a decrease in immunity to know how long the vaccine offers protection.
The Oxford team is not alone in the race to a vaccine. Moderna, an American based biotech company, has released results within the last week showing raised antibody levels for their own vaccine. This vaccine, however, seems to be taking two doses to elicit the type of immune response the Oxford vaccine causes in just one shot.
Prior to the pandemic, Hill had been researching a vaccine for malaria in the Jenner Unit for over 20 years. During this time, the lab focused on the approach of altering the genetic code of a familiar virus to protect against another. This is the method they are currently implementing to find a Covid-19 vaccine in his lab.
With emergency approval from the UK government due to these unprecedented circumstances, the distribution of the vaccine could be accelerated with a few million doses potentially ready for use by September.
