Shots of AstraZeneca + Pfizer Produces better Immune Response – Oxford Study Reveals.

A new study has revealed that a mixed schedule of vaccines where a shot of Pfizer’s COVID-19 vaccine is given four weeks after an AstraZeneca shot will produce better immune responses than giving another dose of AstraZeneca.

The Oxford University study, called Com-COV, compared mixed two-dose schedules of Pfizer and AstraZeneca vaccines, and found that in any combination, they produced high concentrations of antibodies against the coronavirus spike protein.

The data provides support for the decision of some European countries that have started offering alternatives to AstraZeneca as a second shot after the vaccine was linked to rare blood clots.

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“The results show that when given at a four-week interval both mixed schedules induce an immune response that is above the threshold set by the standard schedule of the Oxford/AstraZeneca vaccine.”

An AstraZeneca shot followed by Pfizer produced the best T-cell responses, and also a higher antibody response than Pfizer followed by AstraZeneca.

The results were for combinations of vaccines given at four week intervals to 830 participants.

Com-COV is also looking at mixed schedules over a 12-week interval, and Snape noted that AstraZeneca’s shot was known to produce a better immune response with a longer interval between doses.

In the UK, officials have suggested an 8-week gap between vaccine doses for over-40s and a 12-week gap for other adults.