"We've taken steps to reduce the distribution of health-related misinformation on Facebook, but we know we have more to do. We're currently working with outside experts on additional changes that we'll be announcing soon," a representative for the social media giant said Friday.
In recent years, anti-vaccination groups have been vocal on Facebook, frequently sharing and posting information against vaccines and their safety. At the same time, there has been a rise in cases of measles and other infectious diseases across the United States.
He wrote to Zuckerberg, "Facebook and Instagram are surfacing and recommending messages that discourage parents from vaccinating their children, a direct threat to public health, and reversing progress made in tackling vaccine-preventable diseases."
"There is no evidence to suggest that vaccines cause life-threatening or disabling diseases, and the dissemination of unfounded and debunked theories about the dangers of vaccinations pose a great risk to public health," Schiff wrote.
Now, it seems, Facebook has entered the vaccine battle as it mulls the distribution of anti-vaccination messaging on its platform.
Arthur Caplan, a professor and founding head of the Division of Medical Ethics at NYU Langone Health in New York, said that he is "very supportive" of Facebook's new efforts to police anti-vaccine messaging.
"I'm not trying to say that somebody can't take positions against vaccines on Facebook," he said. "I know people are going to say this is an intrusion into free speech -- many anti-vaxxers will say that -- but no one is saying you can't be anti-vaccination. What we're saying is, you can't lie. You can't fearmonger."
"It is exquisitely contagious," said Dr. Alan Melnick, director of the county health department. "You can be in a room where somebody with measles had left two hours earlier and still get the disease."
Measles kills about 2 of every 1,000 children infected, he said. "The thing that keeps me up at night is having a death, you know, a child die from this."
Vaccination rates in Clark County are low partly because Washington allows parents to opt out of vaccinating their children, not only for medical and religious reasons but for "philosophical" and "personal" ones. Lawmakers are debating removing those provisions for the measles, mumps and rubella vaccine.
"Hundreds of thousands of people in my community have been involved in this issue and have lent support to this bill," Rep. Paul Harris told the State Assembly last week. He represents Clark County and is sponsoring the legislation.
"They're concerned about our community, its immunity and the community safety."
Anti-vaccination activists protested outside the State Assembly during a hearing on the bill last week.