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Nurse who tested positive days after vaccine is reminder protection not instant, 2 doses needed

Posted at 9:08 AM, Dec 30, 2020
and last updated 2020-12-30 18:46:28-05

SAN DIEGO, Calif. — A California nurse tested positive for COVID-19 more than a week after receiving the first dose of the Pfizer vaccine. Health experts are saying this may not be completely unexpected given the time it takes for the vaccine to become protective and the fact that a second dose is needed for full efficacy.

In a Facebook message posted on December 18, Matthew W., an ER nurse at two different hospitals in the San Diego area, talked about receiving the Pfizer vaccine that day. He told KGTV his arm was sore for a day but he suffered no other side effects.

Six days later on Christmas Eve, after working a shift in the COVID-19 unit, Matthew, 45, became sick. He got the chills and later came down with muscle aches and fatigue.

The day after Christmas, he went to a drive-up hospital testing site and tested positive for COVID-19.

"It's not unexpected at all. If you work through the numbers, this is exactly what we’d expect to happen if someone was exposed," said Dr. Christian Ramers, an infectious disease specialist with Family Health Centers of San Diego. He serves on the clinical advisory panel for the county’s vaccine rollout.

He points out, it is possible Matthew was infected before receiving the vaccine, as the incubation period may be as much as two weeks. Dr. Ramers says if Matthew did contract it after the vaccine, it’s still in line with what we know.

"We know from the vaccine clinical trials that it’s going to take about 10 to 14 days for you to start to develop protection from the vaccine," said Dr. Ramers.

Dr. Ramers says he knows of several other local cases where health care workers became infected around the time they received the vaccine. He says all the cases illustrate the fact that results aren’t immediate. Even after you start receiving some protection, it won't be full protection.

"That first dose we think gives you somewhere around 50%, and you need that second dose to get up to 95%," said Dr. Ramers.

Dr. Ramers says Matthew’s story also shows that even with vaccines, the pandemic isn’t going to turn around instantly.

"You hear health practitioners being very optimistic about it being the beginning of the end, but it’s going to be a slow roll, weeks to months as we roll out the vaccine," said Dr. Ramers.

He adds this case is a good reminder of why masks, handwashing, and other COVID protocols are important, even after receiving the vaccine.

Matthew says he’s feeling better since his symptoms peaked on Christmas Day but still feels fatigued.

This story originally reported by Michael Chen at KGTV.

Editor's note: The headline of this article has been adjusted to better reflect the context of the story.

Johns Hopkins Center for Systems Science and Engineering