Mixing Pfizer, AstraZ COVID-19 with Moderna gives better immune response – UK study


December 6 (Reuters) – A major UK study into the COVID-19 vaccine mix found people had a better immune response when they received a first dose of AstraZeneca or Pfizer-BioNTech followed by Moderna nine weeks later , according to the results on Monday.

“We found a very good immune response at all levels…, in fact, above the threshold set by the two-dose Oxford-AstraZeneca vaccine,” Matthew Snape, the Oxford professor behind the vaccine, told Reuters. the test dubbed Com-COV2.

The results in support of a flexible dosage will offer some hope to poor and middle-income countries that may need to combine different brands between the first and second injection if supplies run out or become unstable.

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“I think the data from this study will be particularly interesting and valuable for low- and middle-income countries where they are still rolling out the first two doses of vaccine,” Snape said.

“We show … that you don’t have to stick strictly to getting the same vaccine for a second dose … and that if the program will run faster using multiple vaccines, then it is okay to do so.” . . “

If the AstraZeneca-Oxford (AZN.L) vaccine is followed by a Moderna (MRNA.O) or Novavax (NVAX.O) vaccine, higher antibodies and T cell responses were induced compared to two doses of AstraZeneca-Oxford, according to researchers at the University of Oxford.

The study of 1,070 volunteers also found that one dose of the Pfizer-BioNTech (PFE.N), (22UAy.DE) vaccine followed by an injection of Moderna (MRNA.O) was better than two doses of the Pfizer course. -BioNTech standard.

Pfizer-BioNTech followed by Novavax induced higher antibodies than the two-dose Oxford-AstraZeneca program, although this program induced lower antibody and T cell responses than the two-dose Pfizer-BioNTech program.

Vials containing labels of Pfizer-BioNTech, AstraZeneca, and Moderna coronavirus (COVID-19) vaccine can be seen in this illustrative photo taken on March 19, 2021. REUTERS / Dado Ruvic / Illustration

No safety concerns have been raised, according to the University of Oxford study published in the Lancet medical journal.

Many countries deployed a mix and match long before solid data became available, as countries faced rising infections, low supplies and slow vaccination due to some safety concerns.

The longevity of protection afforded by vaccines has come under scrutiny, with booster doses also being considered amid the increase in cases. New variants, including Delta and Omicron, have now increased the pressure to speed up vaccination campaigns.

Blood samples from the participants were tested against the wild-type, beta, and delta variants, researchers from the Com-COV2 study said, adding that the effectiveness of the vaccines against the variants had declined, but this was consistent across the board. all mixed courses.

The deployment of vaccines using technology from different platforms – such as mRNA from Pfizer and Moderna, the viral vector from AstraZeneca and the protein-based vaccine from Novavax – and in the same timeline is new.

The findings could inform new approaches to vaccination against other diseases, he said.

The study also found that a first dose of the AstraZeneca-Oxford vaccine followed by one of the other study candidates generated a particularly robust response, consistent with the June results.

The study was designed as a so-called “non-inferiority” study – the intention is to demonstrate that the mixture is not significantly worse than standard programs – and compares the responses of the immune system to the baseline responses reported in previous clinical trials of each vaccine.

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Report by Pushkala Aripaka in Bangalore; Editing by Joséphine Mason and Mark Heinrich

Our Standards: Thomson Reuters Trust Principles.


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