On a Friday afternoon in early October this year, 8-year-old Maricia Redondo came home from her third grade class in the San Francisco Bay Area with puffy eyes, a runny nose and a cough.
“On Saturday morning we both got tested,” says 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 her doctor’s test-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 had already fought a harrowing battle against COVID-19 last year — in the fall of 2020. The virus had traveled fast and furious through their working class neighborhood back then, in the East Bay city of San Pablo. Four generations of Vanessa’s family live next door to each other in three different houses there, all connected by a backyard.
Vanessa was also terrified because she couldn’t fathom another round of treatment against a more dangerous variant than she’d faced before. The pandemic has disproportionately struck Latino families across the United States, and 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 may 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-19 again.
“Reinfection is a thing,” says Dr. Peter Chin-Hong, a specialist in infections diseases and professor of medicine at the University of California, San Francisco. “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, [and] immunity has waned.” He says a second infection is still not common, but doctors are starting to see more cases.
Computer models in a recent study suggest that people who have been infected by the virus can expect a reinfection within a year or two if they do not wear a mask or receive a vaccination. The findings show that the risk of a second bout rises over time. A person has a 5% chance