Coronavirus: can ‘mixing and matching’ Covid vaccines boost protection?
One dose each of the Pfizer and Oxford jabs will be given to patients in new trials
The UK’s Vaccine Task Force is planning to test whether a combination of two different coronavirus vaccinations could provide more effective protection than a double injection of just one.
“Instead of a first shot of the Pfizer vaccine followed by a booster three weeks later, the trials will look at using Pfizer for the first shot then Oxford for the second... or vice versa,” The Times reports.
Task force deputy chair Clive Dix says the trials will be “relatively small” as the two vaccines have already gone through full clinical testing.
“Since we’ll have safe vaccines available we should do that study, because then we have the ability to actually produce better immune responses,” he told a press conference.
Although the Oxford vaccine has not yet been approved by safety regulators, “it is widely expected to get the green light within days”, says The Sun.
Experimentation, deliberate or otherwise, may already have accelerated the race to protect people worldwide from Covid-19.
The most promising results in the Oxford clinical trials came from a test group who were accidentally given a half dose of the vaccine followed by a full booster, instead of two full doses as prescribed.
Now, scientists want to test the theory that combining different types of vaccine could offer even greater protection.
“Viral-based vaccines such as the Oxford jab, which is based on a chimp common cold virus, give a much greater cellular response - prompting the T-cells to kill cells infected with the coronavirus,” The Guardian explains. “The mRNA vaccines, like Pfizer’s, tend to generate a bigger antibody response.”
Giving people one shot of each is expected to generate a more powerful and long-lasting immune response to Covid-19.
“Antibodies block the uptake of viruses into cells and the cellular T-cells identify those cells that have been infected and take them out,” said Kate Bingham, chair of the Vaccine Task Force. “You ideally want to have both.”