Oxford-AstraZeneca vaccine appears to reduce coronavirus spread

Data appears promising, but has not yet been peer reviewed

Oxford-Astrazeneca appears to reduce transmission of the coronavirus
Oxford-Astrazeneca appears to reduce transmission of the coronavirus

Results from the Oxford-AstraZeneca coronavirus vaccine trial show that the vaccine may actually help reduce the spread of COVID-19 in addition to effectively preventing infection.

Recent findings from the Oxford-AstraZeneca COVID vaccine trial imply that the vaccine might be effective at reducing coronavirus transmission. However, these results have not yet been peer reviewed -- meaning scientists outside of the trials have not had the opportunity to review the full dataset, which is considered an essential step for scientific integrity.

If the data does happen to be found as it was presented, the findings are encouraging: It would be the first time any vaccine has been documented as impacting transmission of a virus.

Read: Study finds COVID-19 vaccine may reduce virus transmission

Researchers in the Oxford-AstraZeneca study took swabs from volunteers weekly during the trials to see if the volunteers were able to spread the virus. Scientists found 67 percent fewer positive swabs among those who received the vaccine.

Researchers also found that the first dose of the vaccine was 76 percent effective at preventing COVID-19 for three months, with effectiveness going up even higher after the second dose. This information is reassuring, particularly to Britain and other countries that have prioritized administering first doses of the vaccine by pushing second doses until later.

“I think there’s two components to this: One is the protection between the doses; the other is that with the longer gap between the doses, the boost in the immunity and protection after the second dose is greater,” said Dr. Andrew Pollard, head of the Oxford Vaccine Group.

More: UK says new study vindicates delaying 2nd virus vaccine shot

Britain became the first country to authorize AstraZeneca’s inexpensive, easy-to-handle COVID-19 vaccine on Dec. 30.

The Oxford-AstraZeneca has not been authorized for widespread use in the United States like the Pfizer and Moderna vaccines have. The AstraZeneca manufacturer is expected to apply for emergency use authorization with the FDA as early as March -- once data from additional large-scale trials in the U.S. becomes available.

It is possible that the Pfizer and Moderna coronavirus vaccines also reduce virus transmission, but their clinical trials were not designed to measure that, so we simply do not know.

Dr. Anthony Fauci, the top infectious disease expert in the U.S., has made it clear that the nation’s priority should be administering vaccines at the same interval that they were administered during vaccine trials -- which would be 21 days apart for Pfizer vaccines and 28 days apart for Moderna vaccines. This specific spacing enabled the vaccines’ 95 percent efficacy during the trials, and that is still the goal for widespread distribution.

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About the Authors:

Dr. McGeorge can be seen on Local 4 News helping Metro Detroiters with health concerns when he isn't helping save lives in the emergency room at Henry Ford Hospital.