The threat of Zika affecting blood banks is a concern is southern states like Texas and Florida, with some supplies dipping because of people who cannot donate; earlier this year, the FDA issued an advisory that people should refrain from donating for four weeks if they come back from a country with a Zika outbreak or have sex with someone who did.
The good news in Southern California is that the threat of Zika entering the blood stream is having little effect on supplies.
"We've seen some reduction," says Dr. Ross Herron with the Red Cross. "Of our ability to track it, it looks like it's led to about 1/10 of one percent in reduction [of blood supplies]."
The bad news is that Red Cross says there are other reasons that the blood supply in the region is in need of more donations.
"It's summer and the July 4th holiday – people take a lot of vacations around July 4th," he says. "Students are not in colleges and they're not in high schools. That's a significant portion of who donates blood – about 25 percent of our blood comes from high school and college drives."
Dr. Herron is confident that Zika is not an immediate threat to the area, however.
"Before the end of the summer, we may see Zika locally transmitted," he says, "but I don't think it will affect a major percentage of donors."
"If we have local transmission of Zika, then we're going to have to have new measures to be able to protect the safety of the blood supply."