--- title: Measles Vaccine: Why Measles Is So Contagious description: "The measles virus uses the trachea as a trampoline" canonical: https://time.com/3693618/measles-contagious/ author: Mandy Oaklander article:opinion: false article:content_tier: free article:published_time: 2015-02-03T19:09:15.000Z article:modified_time: 2026-08-04T07:59:59.477Z article:section: Health og:title: Why Measles Is the Most Contagious Virus og:description: "The measles virus uses the trachea as a trampoline," og:url: https://time.com/3693618/measles-contagious/ og:site_name: TIME og:image: https://static.time.com/v3/assets/bltea6093859af6183b/blt84bb8f88b2994757/69869145adae441b215434d1/measles2.jpg?branch=production&width=3840&quality=75&auto=webp&crop=16:9 og:image:width: 1200 og:image:height: 675 og:image:alt: 103311832 og:type: article twitter:card: summary_large_image twitter:title: Why Measles Is the Most Contagious Virus twitter:description: "The measles virus uses the trachea as a trampoline," twitter:image: https://static.time.com/v3/assets/bltea6093859af6183b/blt84bb8f88b2994757/69869145adae441b215434d1/measles2.jpg?branch=production&width=3840&quality=75&auto=webp&crop=16:9 ---  # Why Measles Is the Most Contagious Virus ## Video: Science Cop: How Anti-Vaxxers Put Everyone at Risk [Watch (HLS stream): Science Cop: How Anti-Vaxxers Put Everyone at Risk](https://cdn.jwplayer.com/manifests/ai82XWJ8.m3u8) (2:06)  _Published 2014-09-24. TIME's Science Cop Jeffrey Kulger takes on the misinformation coming from opponents of childhood vaccinations_  by [Mandy Oaklander](https://time.com/author/mandy-oaklander/)  ## Mandy Oaklander Oaklander is a senior editor at TIME. Feb 3, 2015 7:09 PM UTC  Thin-section transmission electron micrograph, TEM, of a single measles virus particle or virion Thin-section transmission electron micrograph, TEM, of a single measles virus particle or virionKallista Images—Getty Images  by [Mandy Oaklander](https://time.com/author/mandy-oaklander/)  ## Mandy Oaklander Oaklander is a senior editor at TIME. Feb 3, 2015 7:09 PM UTC Measles is back, and it’s been tearing through the country from California to 13 other states. Already, the [number of cases has broken 100](http://time.com/3692276/measles-numbers-cdc/). But how is it spreading so fast, and why is it so contagious? Roberto Cattaneo, PhD, is the scientist credited with figuring that out. A professor of biochemistry and molecular biology at the Mayo Clinic, he’s been studying the measles virus for 30 years. “It’s the most transmissible virus we know,” he says. Measles, it turns out, has a special way of invading that makes it really, really easy to get out of the host—and into other people. Measles is a respiratory virus, in the same category as influenza. These kinds of viruses get into the lungs and replicate on the linings, called epithelia. Once measles hits the lungs, it doesn’t stay put to breed; instead, it hijacks an immune cell and gets a ride into the immune system, Cattaneo says. “It replicates there, and then it comes out in a very diabolic fashion.” Instead of emerging from the body with a starting point deep inside the lungs, it bursts out from the final few inches of your respiratory system—your trachea, or windpipe. Which means the virus is in precisely the perfect location to be aerosolized when you cough. **MORE** [Chris Christie’s Terrible Vaccination Advice](http://time.com/3692080/christie-vaccines-antivax/) “The measles virus uses the trachea as a trampoline,” Cattaneo says. A single cough or sneeze will hurtle the measles virus through the air in enormous viral quantities, while other respiratory viruses have to travel further to get out. Once out of the host, the measles virus can linger on a surface for two hours, the [CDC says](http://www.cdc.gov/measles/about/transmission.html). And if one person has it, 90% of the people nearby who aren’t immune will also become infected. That explains why it’s spreading so rapidly, and 92% of doctors [now attribute the outbreak](http://time.com/3692152/measles-doctors-poll-parent-vaccination/) to parents not vaccinating their kids. “It is just stupid,” Cattaneo says. “If too many individuals decide that they are above nature or above viruses, the viruses fight back.” In principle, it’s such a simple problem to solve, he says, and raising scientific awareness about how measles transmits will help give vaccination numbers a boost, he hopes. “When more and more people realize what measles virus does, then vaccination will go up again.” _Read next:_ [_More Than 100 Countries Have a Higher Measles Immunization Rate Than the U.S._](http://time.com/3694896/more-than-100-countries-have-a-higher-measles-immunization-rate-than-the-u-s/?xid=time%5Freadnext) [_Listen to the most important stories of the day._](http://time.com/newsletter/the-brief/?sl%5Fautoplay=true&xid=spl-fullbrief-article) ```json [{"@context":"https://schema.org","@type":"NewsArticle","@id":"https://time.com/3693618/measles-contagious/","mainEntityOfPage":{"@type":"WebPage","@id":"https://time.com/3693618/measles-contagious/"},"headline":"Why Measles Is the Most Contagious Virus","datePublished":"2015-02-03T19:09:15.000Z","dateModified":"2026-08-04T07:59:59.477Z","description":"\"The measles virus uses the trachea as a trampoline\"","url":"https://time.com/3693618/measles-contagious/","keywords":["Public Health","measles","vaccination"],"thumbnailUrl":"https://static.time.com/v3/assets/bltea6093859af6183b/blt84bb8f88b2994757/69869145adae441b215434d1/measles2.jpg?branch=production&width=1200&quality=75&auto=webp&crop=1200:675&height=675","author":[{"@type":"Person","name":"Mandy Oaklander","jobTitle":"Oaklander is a senior editor at TIME.","url":"https://time.com/author/mandy-oaklander/"}],"articleSection":"Health","image":[{"@type":"ImageObject","url":"https://static.time.com/v3/assets/bltea6093859af6183b/blt84bb8f88b2994757/69869145adae441b215434d1/measles2.jpg?branch=production&width=1200&quality=75&auto=webp&crop=1200:675&height=675","width":1200,"height":675,"headline":"103311832","caption":"103311832","creditText":"Kallista Images—Getty Images","representativeOfPage":true}],"publisher":{"@type":"Organization","name":"Time","url":"https://time.com/","logo":{"@type":"ImageObject","url":"https://time.com/images/logo.png","width":528,"height":156},"foundingDate":"March 3, 1923","sameAs":["https://www.facebook.com/time","https://www.instagram.com/time/?hl=en","https://twitter.com/time","https://www.pinterest.com/timemagazine"]}},{"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"item":{"@id":"/section/health/","name":"Health"}},{"@type":"ListItem","position":2,"item":{"@id":"/tag/public-health/","name":"Public Health"}},{"@type":"ListItem","position":3,"item":{"@id":"https://time.com/3693618/measles-contagious/","name":"Why Measles Is the Most Contagious Virus"}}]},{"@context":"https://schema.org","@type":"VideoObject","name":"Science Cop: How Anti-Vaxxers Put Everyone at Risk","description":"TIME's Science Cop Jeffrey Kulger takes on the misinformation coming from opponents of childhood vaccinations","thumbnailUrl":"https://cdn.jwplayer.com/v2/media/ai82XWJ8/poster.jpg?width=720","uploadDate":"2014-09-24T20:18:23.000Z","contentUrl":"https://cdn.jwplayer.com/manifests/ai82XWJ8.m3u8","embedUrl":"https://time.com/3693618/measles-contagious/","duration":"PT2M6S","potentialAction":{"@type":"SeekToAction","target":"https://time.com/3693618/measles-contagious/?jw_start={seek_to_second_number}","startOffset-input":"required name=seek_to_second_number"}}] ```