A flurry of headlines this week flooded social media, documenting a seemingly concerning case of Covid-19 in a San Diego nurse who fell ill about a week after receiving his first injection of Pfizer’s coronavirus vaccine.
But experts said the sickness is nothing unexpected: The protective effects of vaccines are known to take at least a couple of weeks to kick in. And getting sick before completing a two-dose vaccine regimen, they said, should not undermine the potency of Pfizer’s product, which blazed through late-stage clinical trials with flying colors.
Reporting that a half-vaccinated person contracted the virus is “really the equivalent of saying someone went outside in the middle of a rainstorm without an umbrella and got wet,” said Dr. Taison Bell, a critical care physician at the University of Virginia. Dr. Bell received his first dose of Pfizer’s vaccine on Dec. 15, and will be getting his second shot soon.
The California nurse, identified as Matthew W., 45, in an ABC10 News report, received his first dose of Pfizer’s vaccine on Dec. 18. Six days later, according to the news reports, he began to feel minor symptoms, including chills, muscle aches and fatigue. He tested positive for the virus the day after Christmas.
Framing the nurse’s illness as news, said Dr. Megan Ranney, an emergency physician at Brown University, implied that it was a departure from the expected — and that there should have been protection about a week after the first vaccine dose. That’s not the case at all.
The timeline of the California nurse’s illness falls well within the window of post-vaccination vulnerability, Dr. Ranney said in an interview. It’s also very likely he caught the virus right around the time he got the shot, perhaps even before. People can start experiencing the symptoms of Covid-19 between two and 14 days after encountering the coronavirus, if they ever have symptoms at all.
A similar situation appears to have recently unfolded with Mike Harmon, the Kentucky state auditor, who this week tested positive for the virus the day after receiving his first dose of an unspecified coronavirus vaccine.