A potential coronavirus vaccine developed by Oxford University in the U.K. with pharmaceutical giant AstraZeneca has produced a strong immune response in a large, early-stage human trial, according to newly released data published Monday in the medical journal The Lancet.
The researchers are calling their experimental vaccine ChAdOx1 nCoV-19. It combines genetic material from the coronavirus with a modified adenovirus that is known to cause infections in chimpanzees. The phase one trial had more than 1,000 participants.
AstraZeneca’s shares fell by about 3% in morning trading.
The researchers said the vaccine produced both antibodies and killer T-cells to combat the infection. Neutralizing antibodies, which scientists believe is important to gain protection against the virus, were detected in participants after 28 days.
The vaccine was found to be well-tolerated and there were no serious adverse events, according to the researchers. Fatigue and headache were the most commonly reported, they said. Other common side effects included pain at the injection site, muscle ache, chills and a fever.
Professor Adrian Hill, director of Oxford University’s Jenner Institute, told CNBC on Monday that the strong immune response means the vaccine is more likely to provide protection against the virus, though nothing is guaranteed. He said scientists hope to begin human trials in the United States in the next few weeks.
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“We are using single-dose and two-dose of the vaccine,” he told “Worldwide Exchange.” “It looks like both give useful immune responses even though after two doses we see stronger immune responses. And to keep following these individuals and start trials elsewhere. Hopefully in the U.S. in the next few weeks.”
The potential vaccine by Oxford is one of at least 100 being developed across the world for Covid-19, which has infected more than 14 million people worldwide and killed at least 606,206, according to data compiled by Johns Hopkins University. At least 23 of them are already in human trials, according to the World Health Organization.
Last week, biotech firm Moderna released promising data on its potential coronavirus vaccine trial, saying it generated a “robust” immune response. That trial included 45 healthy participants and was run by the National Institutes of Health.
AstraZeneca is working with industry partners to manufacture and distribute 2 billion doses of the vaccine with Oxford, it said in June.
The drugmaker is ramping up manufacturing while trials are still underway so the vaccine can be publicly distributed as early as possible if it works, according to Richard Hatchett, CEO of the Coalition for Epidemic Preparedness Innovations, which is working with AstraZeneca on the drug’s production.
While Oxford’s data is promising, scientists warn that questions remain about how the human body responds once it’s been infected with the virus. The answers, they say, may have important implications for vaccine development, including how quickly it can be deployed to the public.
One critical question among scientists is whether antibodies produced in response to Covid-19 offer protection against getting infected again.
Scientists hope the antibodies provide some degree of protection against getting Covid-19, but they can’t say that definitively yet since the virus was first discovered just six months ago. It hasn’t been studied in-depth and some patients appear to have been reinfected after recovering from Covid-19.
—CNBC’s Saheli Roy Choudhury contributed to this report.
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