HOUSTON – As COVID-19 cases and concerns about the Delta variant rise, so do questions about breakthrough cases or cases where people test positive after being fully vaccinated.
“They are actually not uncommon,” said Dr. Linda Yancey, infectious disease specialist at Memorial Hermann. “No vaccine is 100 percent effective and our COVID vaccines are about 95 percent effective.”
The Texas Department of State Health Services said it has tracked 233 “clinically severe” breakthrough cases since February, or cases that resulted in hospitalization or death. Of that total, 43 were deaths.
But the overall number of breakthrough cases is likely higher since the state said it stopped tracking the others in May when the Centers for Disease Control and Prevention switched gears.
Yancey said the numbers are only a fraction of the millions who have already received the shots.
“Vaccines are not impenetrability barriers. They’re more like seatbelts,” she said. “Seatbelts don’t prevent you from getting in traffic accidents but they will absolutely protect you if you do get in one.”
On Friday, the Houston Health Department posted a graphic on Twitter that said less than one percent of fully vaccinated Houstonians who got tested as of last week were positive for COVID-19.
Six COVID-related deaths of Houstonians are vaccine breakthrough cases and each had pre-existing conditions or was severely immunocompromised, the city’s health department said.
“If you have a breakthrough infection, in general, the breakthrough infection is much milder than those who are being infected for the first time,” said Dr. Pedro Piedra, a pediatric infectious disease specialist at Baylor College of Medicine.
Can vaccinated people who get sick give the virus to someone else?
“They have the potential to spread it to others but for a much shorter time period,” said Piedra.
Piedra’s main concern is unvaccinated, who he said make up most of the people now hospitalized or dying from the virus.
Yancey said most of the people she’s now seeing in her hospital are between their 20′s and 40′s and are not vaccinated.