Coronavirus 'disappearing' so fast Oxford vaccine has 'only 50% chance of working'

Henrietta Brewer
May 25, 2020

The scientists are not planning to deliberately infect volunteers with the virus to test the vaccine, so instead, they require relatively high rates of the virus to be spreading through the community to evaluate success.

"We said earlier in the year that there was an 80% chance of developing an effective vaccine by September". "Over all, I would say this is good news". This vaccine is moving through a compressed, and somewhat unconventional, trial timeline having already dosed over 1,000 subjects as part of its first safety phase testing. Proof of its effectiveness will require trials in thousands, perhaps hundreds of thousands, more people.

The coronavirus health crisis continues to devastate countries around the world. Numerous candidates work in different ways, and are made with different technologies, increasing the odds that at least one approach might succeed.

Pollard noted that people over 70 often don't get as much protection from vaccines as younger people. And on Wednesday, Dr. Barouch and his colleagues published a study showing their prototype vaccine protected monkeys from coronavirus infection. While the data is being drawn from a short testing period (which is one of the biggest shortcomings of many vaccine trials going on right now), there is also a possibility of side-effects which was seen in some participants. Vaccines by Johnson & Johnson, Sanofi and Merck & Co are a month or two behind the frontrunners and "may get added over the course of the summer" following early-stage human trials, Collins said.

Other leading candidates - including one from the NIH and Moderna Inc., and another by Inovio Pharmaceuticals - simply inject a piece of the coronavirus genetic code that instructs the body itself to produce spike protein that primes the immune system.

Following this, the team regularly tested the volunteers" blood to assess if the vaccine activated the two parts of the body's immune system: The "humoral response' and the T-cell response.

Adrian Hill, also from the Oxford Vaccine Group, suggests the unusual irony the researchers now face is that decreasing levels of community transmission could significantly slow progress in testing the vaccine.

Presidential Spokesperson Harry Roque said the Department of Science and Technology (DOST) has been directed to lead the preparations for such clinical studies, including identifying the study sites and researchers to be involved in the vaccine trials as well as getting the approval of the ethics board. "If you're comparing vaccines, the adenovirus ones so far seem to be on the lower end of the spectrum". "We need to be urgently exploring other vaccine candidates".

Only a subset of people in the new trial produced neutralizing antibodies to the coronavirus, the kinds of molecules needed for immunity.

The antibody titer (the measure used for antibody levels) for both binding and neutralising antibodies was directly proportional to the dose of the vaccine.

As per the study, about 81% of all the participants (83% in the low-dose group, 83% in the middle-dose group and 75% in the high-dose group) showed at least one adverse reaction to the vaccine within the first seven days.

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