Vaccinate Networks, Not Everyone

By vaccinating those individuals with the largest social networks, whole populations could be protected from disease outbreaks more efficiently. Karen Hopkin reports

Illustration of a Bohr atom model spinning around the words Science Quickly with various science and medicine related icons around the text

Join Our Community of Science Lovers!


On supporting science journalism

If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.


[The following is an exact transcript of this podcast.]

You’ve probably heard of the whole six degrees of separation thing. It predicts that, on average, you’re no more than six links away from any other person on the planet. Like your roommate runs into a woman whose brother is a writer for Desperate Housewives. Which means you’re only six invites away from having lunch with Marcia Cross’s nannies.

The concept stems from the fact that people have social networks, and those networks tend to intersect. But the importance of this “small world” phenomenon extends beyond whose email address you have on your Blackberry. Now scientists think they can take advantage of these networks to design more efficient vaccination programs.

According to an international team of physicists, the most effective way to protect a population from disease is to immunize people who have the largest networks. If you can keep the most highly connected people from infecting their friends, neighbors, co-workers, you can halt an epidemic. And you may only have to vaccinate half the number of people you would normally. The findings will appear in an upcoming issue of Physical Review Letters. The biggest problem with such a program—people are bound to feel left out when they’re told that they don’t need a shot.

—Karen Hopkin 

60-Second Science is a daily podcast. Subscribe to this Podcast: RSS | iTunes

It’s Time to Stand Up for Science

If you enjoyed this article, I’d like to ask for your support. Scientific American has served as an advocate for science and industry for 180 years, and right now may be the most critical moment in that two-century history.

I’ve been a Scientific American subscriber since I was 12 years old, and it helped shape the way I look at the world. SciAm always educates and delights me, and inspires a sense of awe for our vast, beautiful universe. I hope it does that for you, too.

If you subscribe to Scientific American, you help ensure that our coverage is centered on meaningful research and discovery; that we have the resources to report on the decisions that threaten labs across the U.S.; and that we support both budding and working scientists at a time when the value of science itself too often goes unrecognized.

In return, you get essential news, captivating podcasts, brilliant infographics, can't-miss newsletters, must-watch videos, challenging games, and the science world's best writing and reporting. You can even gift someone a subscription.

There has never been a more important time for us to stand up and show why science matters. I hope you’ll support us in that mission.

Thank you,

David M. Ewalt, Editor in Chief, Scientific American

Subscribe