Story at a glance
- Christopher Murray said that vaccinated individuals may be contributing to the spread of COVID-19.
- As the delta variant becomes the most dominant strain, Murray posits that not testing vaccinated individuals may overlook possible transmission points.
- New data suggests that the delta variant may also be more resilient to the Pfizer vaccine.
As some states report marked upticks in COVID-19 infections while the delta variant becomes the most common strain in the U.S., public health experts are encouraging further vaccinations to help curb transmission.
Some experts, however, warn that vaccinated individuals may still be capable of contracting and transmitting COVID-19.
Speaking to Insider, Christopher Murray, the director of the Institute for Health Metrics and Evaluation, said that not testing vaccinated people — as the U.S. Centers for Disease Control and Prevention (CDC) recommends — may be overlooking some transmission.
"We actually have states where hospitalizations are going up more than cases," Murray said, adding that "we're probably missing a bunch of transmission in vaccinated individuals."
National data notes that more than 30 states continue to see rises in the number of COVID-19 infections. Experts attribute this to gaps in vaccinations and the rise of the contagious delta variant.
While vaccines are beneficial in preventing severe infections, contracting the virus and transmitting COVID-19, vaccinated individuals are never completely protected against COVID-19. Breakthrough infections are possible, and the delta infectivity rate is still very high.
"That's the scary part," said Hugh Cassiere, director of critical care services at the Sandra Atlas Bass Heart Hospital at North Shore University Hospital, on Long Island, New York, to NBC. "Delta has such a high infectivity rate."
Other data emerging from Israel suggest that the Pfizer vaccine is less effective against infections caused by the delta variant, which may explain the uptick in U.S. infection despite widespread vaccinations.