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Coronavirus: what does suspension of Oxford-AstraZeneca trials tell us about vaccine development? | South China Morning Post
Independent committee must investigate any possible link between participant’s unexplained illness and the trial vaccine
Thousands have received test vaccine and the company plans to enroll up to 50,000 volunteers worldwide for the last stage of trials
Oxford University and pharmaceutical giant AstraZeneca have suspended clinical trials of a potential Covid-19 vaccine pending an independent investigation after “a potentially unexplained illness” was found in a volunteer, but scientists said it was too early to tell if it was linked to the vaccine.
If the illness was found to have been caused by the experimental vaccine, the investigators would then have to find out if it had to do with the adenovirus vector used in it, or the vaccine construct that was used to express the antigen, he said. The information would then be shared with other vaccine developers using similar technology, he added.
The Oxford/AstraZeneca vaccine candidate uses an adenovirus from chimpanzees as a vector to express the spike protein of the coronavirus that causes Covid-19. Johnson & Johnson, Russia’s Sputnik V vaccine candidate and Chinese pharmaceutical firm CanSino use other types of adenoviruses as vectors to express the protein.
Farrar said there had been no similar incident in trials for other adenovirus vector vaccines.
“These adenovirus vectors have been in tens of thousands of people … I am not aware of any issue like this in any of the adenovirus vector trials that have been conducted over the last few years, in Mers, previously in Sars, or in Ebola.”
“If it is related to the vaccine, then they may need more time to find the cause. They can resume as soon as they determine it is not an adverse effect of the vaccine. Of course, they have to negotiate with the regulator. They also have to determine how common such a case is in the trials,” according to the head of the public health laboratory sciences division at the University of Hong Kong.
This is the second time the Oxford University/AstraZeneca coronavirus vaccine trials have been put on hold for independent investigation since they began in April.
According to an article posted by Oxford scientists on The Conversation website on Tuesday, the team and its partners have vaccinated about 17,000 people in Britain, Brazil and South Africa in trials, with half receiving another vaccine for comparison. Phase 3 trials also started in the US in August and the company is planning to enroll up to 50,000 volunteers worldwide for the last stage of trials.
A report by The New York Times said a volunteer in Britain had suffered from transverse myelitis, a spinal inflammation
If it is found to be transverse myelitis, that could be a serious illness, said Helen Petousis-Harris, associate professor of vaccinology at the University of Auckland, but she noted the condition could be caused by other factors.
“While not yet confirmed, it is biologically possible to be related to the vaccine. It is also more likely to be caused by something else, particularly a viral infection,” she said.
“There are many infectious agents that can trigger this kind of event, such as influenza and the herpes viruses. Vaccines are a plausible trigger but less likely.”
Given that thousands of volunteers take part in large-scale clinical trials, it is possible that some might have unknown health problems.
“When you have what will ultimately be hundreds of thousands of people under observation in clinical trials, some will get sick, especially when you start recruiting older people into these studies,” Petousis-Harris said. “When this happens sometimes the trial will need to be halted while the event is investigated, and a lot of questions answered.”
===================================================
If it's the adenovirus & others work as well, there is that choice.
Independent committee must investigate any possible link between participant’s unexplained illness and the trial vaccine
Thousands have received test vaccine and the company plans to enroll up to 50,000 volunteers worldwide for the last stage of trials
Oxford University and pharmaceutical giant AstraZeneca have suspended clinical trials of a potential Covid-19 vaccine pending an independent investigation after “a potentially unexplained illness” was found in a volunteer, but scientists said it was too early to tell if it was linked to the vaccine.
If the illness was found to have been caused by the experimental vaccine, the investigators would then have to find out if it had to do with the adenovirus vector used in it, or the vaccine construct that was used to express the antigen, he said. The information would then be shared with other vaccine developers using similar technology, he added.
The Oxford/AstraZeneca vaccine candidate uses an adenovirus from chimpanzees as a vector to express the spike protein of the coronavirus that causes Covid-19. Johnson & Johnson, Russia’s Sputnik V vaccine candidate and Chinese pharmaceutical firm CanSino use other types of adenoviruses as vectors to express the protein.
Farrar said there had been no similar incident in trials for other adenovirus vector vaccines.
“These adenovirus vectors have been in tens of thousands of people … I am not aware of any issue like this in any of the adenovirus vector trials that have been conducted over the last few years, in Mers, previously in Sars, or in Ebola.”
“If it is related to the vaccine, then they may need more time to find the cause. They can resume as soon as they determine it is not an adverse effect of the vaccine. Of course, they have to negotiate with the regulator. They also have to determine how common such a case is in the trials,” according to the head of the public health laboratory sciences division at the University of Hong Kong.
This is the second time the Oxford University/AstraZeneca coronavirus vaccine trials have been put on hold for independent investigation since they began in April.
According to an article posted by Oxford scientists on The Conversation website on Tuesday, the team and its partners have vaccinated about 17,000 people in Britain, Brazil and South Africa in trials, with half receiving another vaccine for comparison. Phase 3 trials also started in the US in August and the company is planning to enroll up to 50,000 volunteers worldwide for the last stage of trials.
A report by The New York Times said a volunteer in Britain had suffered from transverse myelitis, a spinal inflammation
If it is found to be transverse myelitis, that could be a serious illness, said Helen Petousis-Harris, associate professor of vaccinology at the University of Auckland, but she noted the condition could be caused by other factors.
“While not yet confirmed, it is biologically possible to be related to the vaccine. It is also more likely to be caused by something else, particularly a viral infection,” she said.
“There are many infectious agents that can trigger this kind of event, such as influenza and the herpes viruses. Vaccines are a plausible trigger but less likely.”
Given that thousands of volunteers take part in large-scale clinical trials, it is possible that some might have unknown health problems.
“When you have what will ultimately be hundreds of thousands of people under observation in clinical trials, some will get sick, especially when you start recruiting older people into these studies,” Petousis-Harris said. “When this happens sometimes the trial will need to be halted while the event is investigated, and a lot of questions answered.”
===================================================
If it's the adenovirus & others work as well, there is that choice.
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