Experts weigh in on timing for second covid-19 vaccine doses

WASHINGTON - Just how important is timing when it comes to the second dose of the Pfizer and Moderna vaccines?

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Walgreens is now adjusting its vaccine scheduling process after being asked to do so by the CDC. They were spacing Pfizer vaccines 28 days apart instead of recommended 21 days, because it was just easier to schedule them the same as the Moderna shot.

So what’s the big deal, why ask Walgreens to change their process?

Does the vaccine actually start to become less effective as you move beyond 21 days?

Both Dr. Mohammad Sajadi, Associate Professor with the University of Maryland School Of Medicine’s Institute of Human Virology and Dr. Amesh Adalja, a Senior Scholar with Johns Hopkins Center for Health Security tell FOX 5 no.

In fact, Dr. Sajadi believes the opposite me be true, saying, "Actually the longer the interval is between the first vaccine and the second one your body will mature more and probably respond in a better way theoretically."

They say the CDC likely asked Walgreens to stick to the 3 week timeline for Pfizer shots simply because you don’t have full efficacy until you get that second dose.

"We know people have gotten sick after the first shot," says Sajadi.

Once you are fully vaccinated, Dr. Adalja Is feeling more and more confident that your risk of being a carrier and infecting unvaccinated people in your household is actually quite low. "I think the data is becoming really clear," he says. "If you’re fully vaccinated it’s highly unlikely. Doesn’t mean it’s 100 percent but it’s extremely unlikely."