Clinical trials of vaccines against new variants of coronavirus will start in the summer to ensure updated boosters are available for the autumn if needed, Oxford’s lead vaccine researcher has told MPs.
Prof Sarah Gilbert said her team was producing initial stocks of vaccine that targeted new variants which were at least partially resistant to the current vaccines being rolled out. The stocks will be passed to AstraZeneca for large-scale manufacturing.
Updated versions of the vaccine are being developed as a precaution in case new variants of coronavirus substantially evade immunity provided by the shots being administered today.
Several new variants have already cropped up around the world with mutations that appear to make them less susceptible to vaccines. A small-scale trial in South Africa found a variant that emerged there, and which has since arrived in the UK, was partially resistant to the Oxford vaccine. Other vaccines from Novavax and Johnson & Johnson also appear less effective against the variant.
While it is still uncertain whether the vaccines will need to be changed, Gilbert said the necessary work had begun and a decision would need to be taken in the summer.
“We need to make preparations so that everything is in place, if it turns out that we do need to do it,” Gilbert told the Commons science and technology committee. “Currently, the plans are to be ready for an immunisation campaign in the autumn, so before going into the winter season we would have a new variant vaccine available if it turns out that is what’s going to be required.
“If we see the emergence of a new strain very close to that date, it is going to be difficult to go through this whole process, because we do need to conduct a clinical study and get regulatory approval, in time to be vaccinated before the winter,” she added.
“I think we need to make a decision over the summer. We will start to get data from the clinical trials on the immune responses to the variant vaccine, both against the virus variant and against the original virus, and we will then be able to monitor the situation and decide what should be happening in the autumn.”
Gilbert said her team was planning for clinical trials to take place from the early summer with batches of the new variants of the vaccine. “We have been discussing with regulators the approach that we will need to take for a strain change, and this is going to be quite similar to the approach taken for a strain change in flu. It’s not expected to require any further efficacy trials, any phase 3 trials, it will be a trial in hundreds of people rather than hundreds of thousands.”
Further trials are under way to assess whether mixing vaccines provides better protection by stimulating the immune system in different ways. Other options under development are vaccines based on nasal sprays and pills, Gilbert added.