The US Is Throwing Measles a “Welcome Back” Party!

I consider America to be a very hospitable place, which is why I'm thrilled to see the US welcoming measles back into the country after 20 years of banishment. Good to have you back measles! You've been missed.

Plus, I think the red splotches all over your body make for a bold fashion statement.

Ok but seriously, let’s talk about this recent resurgence of measles. Measles is an infectious virus that usually manifests as a red, itchy rash 8-12 days after exposure [8,9]. It is highly contagious, can be spread through coughing and sneezing, and will remain alive for up to two hours outside the body [8,9]. It’s a nasty little bugger and complications can include ear infections, diarrhea, pneumonia (infection of the lungs), encephalitis (swelling of the brain), seizures, and death [7].

Measles was declared eliminated back in 2000 within US borders by the CDC [1]. By 2002, it had been eliminated in North and South America [1]. Elimination of infections is defined as “reduction to zero…the incidence of infection caused by a specific agent in a defined geographical area as a result of deliberate efforts; continued measures to prevent re-establishment of transmission are required” [2]. In the US, the overall measles incidence remained less than 1 case per 1,000,000 people from 1997 through 2013 [3]. Of the cases reported, 65% were in unvaccinated patients and 20% had an unknown vaccination status [3]. In all likelihood, the measles occurrences in the unvaccinated patients probably came from the 6 to 11 month (4.1 cases per 1,000,000) and 12 to 15 month age groups (3.6 cases per 1,000,000), as children younger than 12 cannot get the vaccination while others are delayed in their vaccination schedules [3,4]. 

Don't freak out over these unvaccinated infants getting infected from parents that refuse to give their kids the MMR vaccine. Remember, these numbers are from when measles was still classified as eliminated. The effects of vaccinophobia did not manifest via increased measles cases until 2014.

603 cases were reported from January 1st to October 31st 2014, which means there are more coming [5]. In the first 10 months of this year, we have more reported cases than in the past 20 years and more total cases than in the past 5 years combined. That is absurd! But why the sudden spike? Walter Orenstein, M.D., and Katherine Seib, M.S.P.H. suggest two possible explanations in their New England Journal of Medicine article, Mounting a Good Offense Against Measles.

1 – “Susceptible U.S. residents who travel to countries where measles is endemic or epidemic and susceptible residents of those countries who travel to the United States are bringing the virus here.”
2 – “An increasing number of parents in this country are hesitant to have their children vaccinated, and such hesitancy has resulted in an accumulation of unvaccinated populations who can become infected and maintain transmission.”

So why all the fuss over measles? What’s so bad about it anyway? Two reasons: it’s highly contagious and it can kill you dead. Between the 16th and 20thcenturies (1500 - 1999) an estimated 200 million people died of measles [6]. After the measles vaccine became available in 1963, and the combination measles-rubella vaccine in 1971, disease incidence fell quickly [6].

Measles happens to possess the title of being one of the most infectious diseases with a reproduction rate (R0) between 12 and 18 [1,10,11]. This means that once a person has measles, they are capable of passing it on to as many as 18 other people. To see how that stacks up, I've included a comparison to other communicable diseases from NPR.

To keep an outbreak from occurring, we need 92-94% of the population to be vaccinated to ensure herd immunity (see more on herd immunity here) [1]. This threshold is “higher than the thresholds for almost all other vaccine-preventable diseases.” [1].

After reading all that you may be thinking to yourself, “Measles sounds pretty lousy. How do I go about protecting myself and my family?” Well, the graphic below provides some pretty stellar information. If you click on it, you will be taken to a CDC website that can provide you with further assistance.

So if this post was a little too Debbie Downer for you, I'll leave you with a few measles factoids that may brighten your outlook [12].

  • Estimated global coverage with the first dose vaccine is 84% as of 2012
  • The number of countries providing a second dose vaccine increased from 96 (50%) in 2000 to 145 (75%) in 2012
  • 144 million children were vaccinated against measles during vaccination campaigns
  • In 2012, annual reported measles incidence was 33 per 1,000,000, a decline of 77% from 146 per 1,000,000 in 2000
  • Estimated measles deaths decreased 78%, from 562,400 to 122,000
  • An estimated 13.8 million deaths were prevented by measles vaccination during 2000–2012

Sources

1 - http://www.nejm.org/doi/full/10.1056/NEJMp1408696

2 - http://www.cdc.gov/mmwr/preview/mmwrhtml/su48a7.htm

3 - http://archpedi.jamanetwork.com/article.aspx?articleid=1787786

4 - http://www.cdc.gov/vaccines/hcp/vis/vis-statements/mmr.pdf

5 - http://www.cdc.gov/measles/cases-outbreaks.html

6 - http://archpedi.jamanetwork.com/article.aspx?articleid=1787785

7 - http://www.cdc.gov/vaccines/pubs/pinkbook/meas.html#complications

8 - http://www.nlm.nih.gov/medlineplus/ency/article/001569.htm

9 - http://www.cdc.gov/measles/about/transmission.html

10 - https://www.elsevier.com/books/vaccines/plotkin/978-1-4557-0090-5

11 - http://smm.sagepub.com/content/2/1/23.abstract

12 - http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6305a5.htm