COVID Cases In LA Are Rising. Why Does The Delta Variant Spread So Much Faster?

In the month and half since California officially re-opened, the Delta variant has delivered a hard reality check to Los Angeles County. New daily cases have been above 3,000 since Friday.

Dr. Dean Blumberg, professor of medicine and Chief of Pediatric Infectious Diseases at UC Davis, says the Delta variant spreads much faster than the original COVID-19 virus. Why is that?

"Well, there's two things. One is that is does bind tighter to our ACE-2 receptors and that tighter bond makes it easier for it to infect us. The other thing is that it replicates more rapidly, and that's why you get about 1,200 times higher concentration in respiratory secretions compared to previously circulating strains," Blumberg said.

On KPCC's Airtalk, he explained that the Delta variant requires less exposure time to infect someone — and it might spread over longer distances. Also, it's largely being spread by people who don't show symptoms.

Fully vaccinated people are also testing positive. That doesn't mean the vaccines aren't effective, Blumberg said.

"Just because there are breakthrough infections does not mean that the vaccine's not working. The vaccines are working very well in terms of preventing severe disease, hospitalization and death," he said.

On Monday, L.A. County reported almost 1,100 COVID-19 patients are in hospitals and there were five new deaths attributed to the virus on Sunday.