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Phase 3 Clinical Trial Of Pfizer Covid-19 Vaccine Remains Highly Effective After Six Months

MIAMI (CBSMiami) - Pfizer confirmed this week that an ongoing Phase 3 clinical trial of its coronavirus vaccine remains highly effective for at least six months after the second dose.

Many interpreted this to mean the vaccine protection only lasts for six months and that is not the case.

Dr. Aileen Marty, an infectious disease expert with FIU, says "We can't know how long it is going to last, at least until a year has passed. At six months, we are at 91.3 percent protection, and that absolutely outstanding."

The vaccine also appeared to work against a variant first detected in South Africa, the companies said.

The vaccines are based on memory cells that trigger immunity.

'We have to see how long the memory cells last, if they last a long time, we may not need annual boosters. But we won't know till time has passed," said Marty.

"Important to know is that vaccines are continuously tested, evaluated, studied, research is ongoing."

"Remember the vaccines are under emergency use authorization, so even if they were licensed, we would be doing what we call phase four trials, where we continue to monitor what is going on with a new product both safety and efficacy," she adds.

And how about the other vaccines that are going into the arms of Americans?

"I wouldn't be surprised at all if Moderna or J&J did a study if they'd get similar results," said Dr. Anthony Fauci.

Reaction on the street has been mixed.

"I hope they find it last longer than six months. I don't want to go through this every six months," said Carlos Irvin.

"It is great comfort that for six months, we are probably well protected, extremely well protected," said Lissette Alvarez.

"I see a study where it could be longer for now. It is better than not getting it," said Jose Alcala.

This week, the companies said the vaccine is safe and strongly protective in kids as young as 12, based on a study of 2,260 U.S. volunteers.

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