On a Friday afternoon in early October, 8-year-old Maricia Redondo came home from her third grade class in San Pablo with puffy eyes, a runny nose and a cough.
“On Saturday morning we both got tested,” said Vanessa Quintero, Maricia’s 31-year-old mother. “Our results came back Monday that we were both positive.”
Vanessa stared at her phone in shock and called the Kaiser result hotline again, in disbelief.
“This is wrong,” she thought. “I hung up and dialed again. It’s positive. This is wrong. I hung up again. And then I did it again!”
She was freaking out for two reasons. First, her large, extended family fought a harrowing battle against COVID-19 last fall. Four generations live next door to each other in three different houses in San Pablo, all connected by a backyard. The virus traveled fast and furious through their homes this time last year.
Second, Vanessa couldn’t fathom another round of treatment against a more dangerous variant. Delta is currently the predominant variant in the U.S., according to the U.S. Centers for Disease Control and Prevention. It’s twice as contagious and can potentially cause more severe illnesses than previous variants in unvaccinated people.

The family’s bad luck was uncanny. Research suggests immunity against a natural infection lasts about a year. And here it was almost exactly the same time of year and the family was fighting COVID again.
“Reinfection is a thing,” said UCSF infectious disease expert Dr. Peter Chin-Hong. “It probably manifests itself more when the variant in town looks different enough from the previous variants. Or enough time has elapsed since you first got it where immunity has waned.”

