• Video
  • Shop
  • Culture
  • Family
  • Wellness
  • Food
  • Living
  • Style
  • Travel
  • News
  • Book Club
  • Newsletter
  • Privacy Policy
  • Your US State Privacy Rights
  • Children's Online Privacy Policy
  • Interest-Based Ads
  • Terms of Use
  • Do Not Sell My Info
  • Contact Us
  • © 2026 ABC News
  • Wellness

Unvaccinated Clusters Leave Communities Vulnerable to Illness, Research Shows

1:57
Parents Who Don't Vaccinate Appear to Live in Same Areas
Jordan Siemens/Getty Images
BySYDNEY LUPKIN
January 20, 2015, 4:21 PM

— -- A study of vaccination rates among children in northern California showed that there are "clusters" where parents aren't vaccinating their children -- and they're at risk for catching preventable diseases.

Researchers at Kaiser Permanente studied records of more than 150,000 children in the Bay Area from birth to age 3, and identified five clusters where children were under-immunized, meaning their parents either refused to vaccinate them or they missed one or more vaccines. The percentage of under-immunized children in these often well-educated clusters was between 18 percent and 23 percent. Outside them, only 11 percent of the children were under-immunized.

Related Articles

Why Some Schools Have 'Cupcake Amnesty' and Others Have Cupcake Bans

Related Articles

3-Year-Old Cancer Patient Tells Friend She's Going to Disneyland

Related Articles

Man Allegedly Keeps Crowdsourced Funds Raised in Sick Baby's Name

ABC News Chief Health and Medical Editor Dr. Richard Besser said not only does this put the unvaccinated children at risk for getting illnesses such as whooping cough, but it puts those around them at risk because vaccines aren't "100 percent protective." The measles vaccine, for instance, is 95 percent protective.

"The more child you're around who didn't get vaccinated, the more likely you are to be exposed to that and get the disease even if you were vaccinated," he said today on ABC News' "Good Morning America."

Host Lara Spencer asked him what he would say to parents who think there are "just too many vaccines."

"As a pediatrician, I've seen so many of these diseases cause suffering in children," Besser said. "And every time we get a new vaccine, I think it's a wonderful thing."

He stressed the importance of getting vaccines on time and using online tools to find out vaccination rates in their schools. If they can send their child to a school with higher vaccination rates, they should, he said.

Up Next in Wellness—

Adolescent and young adult cancers increase risk of developing future cancers

April 13, 2026

Teen with kidney disease finds donor living minutes away

April 10, 2026

Her battle with cancer went viral. After her death, the impact of her advocacy is still felt

April 8, 2026

Gabrielle Union shares emotional tribute after dad dies following dementia battle

April 6, 2026

Shop GMA Favorites

ABC will receive a commission for purchases made through these links.

Sponsored Content by Taboola

The latest lifestyle and entertainment news and inspiration for how to live your best life - all from Good Morning America.
  • Contests
  • Terms of Use
  • Privacy Policy
  • Do Not Sell My Info
  • Children’s Online Privacy Policy
  • Advertise with us
  • Your US State Privacy Rights
  • Interest-Based Ads
  • About Nielsen Measurement
  • Press
  • Feedback
  • Shop FAQs
  • ABC News
  • ABC
  • All Videos
  • All Topics
  • Sitemap

© 2026 ABC News
  • Privacy Policy— 
  • Your US State Privacy Rights— 
  • Children's Online Privacy Policy— 
  • Interest-Based Ads— 
  • Terms of Use— 
  • Do Not Sell My Info— 
  • Contact Us— 

© 2026 ABC News