Mixing Covid jab doses boosted animals' immune response

Animal studies suggest that combining doses of different coronavirus vaccines can produce a better immune response, according to one expert.

The investigation into whether different coronavirus vaccines can be safely mixed for the first and second dose aims to give “flexibility” and “resilience” to the UK vaccination program, the study’s lead investigator said.

The study, which is looking at whether the Oxford / AstraZeneca and Pfizer vaccine doses can be combined, is expected to add two additional bursts – Moderna and Novavax.

Commenting on the so-called mix-and-match trials, Professor Anthony Harnden, vice-chairman of the Joint Committee on Vaccination and Immunization (JCVI), said: “If we can mix and match we will be much more flexible – we may have different vaccine boosters in the fall -Campaigns can be used.

“And indeed, mixed schedules – and this is a big May – can offer better protection in the long run, and that will be very interesting to see.”

Matthew Snape, Associate Professor of Pediatrics and Vaccine at Oxford University, is a lead investigator on the study. He was asked on Times Radio why mixing vaccines could be a good thing or a bad thing.

He replied, “Ultimately, they all actually create an immune response against the spike protein and it is delivered by different platforms.

“So we think it’s likely that you’ll see a good reaction with these different combinations, but we don’t know until we look at it.

Prof. Snape added, “The main aim of this study is to increase the flexibility of the UK schedule and resilience to problems with the delivery or availability of any of the vaccines.”

“We want to know if the immune responses are as good as if you were giving the same vaccines if you were giving different vaccines for the first and second dose.”

“We know that we get very good protection against Covid-19 if you give the same vaccine for the first and second dose.

“And we’re going to see if the immune response, as well as the profile and post-vaccine responses, are as good when you mix the vaccines, which would greatly increase flexibility.”

“We need the evidence before we can make these decisions about whether or not it is the right thing to do.

“There are some suggestions from animal studies in mice that if you combine the AstraZeneca-type vaccines with an RNA-type vaccine, for example, that you may get a better immune response, and in some ways this actually seems to produce a better immune response.

“So it will be interesting to see if we can see that in humans too.”

Prof. Snape also said a pause in the launch of the Johnson & Johnson vaccine in Europe underscores the need for research.

When asked about the Johnson & Johnson vaccine, which has not yet been approved by the UK Medicines Agency, he told Times Radio, “We knew there was a high likelihood that unforeseen things would happen, whether it was a problem with ( a) manufacturer. or different deliveries to different countries or things like these safety signals. “

He added, “So it underscores the need for this type of study that looks at how to add great flexibility and resilience to the vaccination schedule by looking at all possible combinations.”


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