Category Archives: Vaccines

CDC: Measles “eliminated” in U.S. despite most reported cases since ’96…?

Measles

Measles: Gone, but not gone

Yes, that headline does look a bit confusing. There have been 214 cases of measles in the United States as of mid-October, the most since 1996, and yet the Centers for Disease Control and Prevention has listed the U.S. as a country in which measles has been “eliminated” since 2000. How is that possible? It’s all in the definition:

For measles to be considered no longer eliminated from the United States, person-to-person transmission of the virus would need to persist in the country for a year, said Dr. McLean, an epidemiologist in the National Center for Immunization and Respiratory Diseases of the CDC in Atlanta.

“We’ve been getting a lot of imported cases, but the spread has been very limited,” she said in an interview. “As long as there is measles elsewhere in the world, [the United States] is going to get importations.”

In other words, since the outbreaks have been due to someone entering the country with measles, and have been limited in size and relatively easily contained, we’re still technically measles-free. Thank the relatively high rate of measles vaccination nationwide for that.

Surprisingly (at least to me) most of the imported cases came from the European Union, which has had 28,000 cases so far this year, half of those in France. The outbreak has been attributed to low vaccination rates resulting from the now-discredited link between measles vaccine and autism.

Here’s some info about vaccination status for those 214 U.S. cases:

Among the 214 U.S. cases, 187 were in U.S. residents, and 180 cases (84%) occurred in people who had either been previously unvaccinated for measles or had an unknown vaccine status. The total also included 19 people (9%) who had previously received just one measles vaccine dose (the CDC recommends that people receive two doses to better insure immune coverage), and 15 (7%) with evidence of having received two doses, Dr. McLean said.

The 7% failure rate for the two-dose vaccine series is in keeping with its overall 95% effectiveness.

But…the news from Canada is more worrisome. 757 measles cases have been reported in rural Quebec this year, 13% of which occurred in fully vaccinated individuals. This higher-than-expected infection rate among vaccinated individuals suggests there may be something more than just a failure to vaccinate going on. Problems with the vaccine itself? We’ll see…the investigation is ongoing.

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Mumps in Berkeley

"Sorry about your testicles, Greg."

There are now close to 30 confirmed or probable cases of mumps on the campus of the University of California at Berkeley (henceforth “Cal” – Go Bears!), and that number will no doubt increase.

Most people are a bit mystified about mumps. It’s that chipmunk cheek infection that little kids get, right? is a typical response I hear from parents in my practice when I ask them about it. Well, yes, mumps is fairly chipmunk-cheeky, but it can do a lot more than make a child look like an extra in a Chip-n’-Dale cartoon.

Here’s a science-heavy description from the American Academy of Pediatrics’ Red Book.

Mumps is a systemic disease characterized by swelling of one or more of the salivary glands, usually the parotid glands. Approximately one third of infections do not cause clinically apparent salivary gland swelling and may manifest primarily as respiratory tract infection. More than 50% of people with mumps have cerebrospinal fluid pleocytosis, but fewer than 10% have symptoms of central nervous system infection. Orchitis is a common complication after puberty, but sterility rarely occurs. Other rare complications include arthritis, thyroiditis,mastitis, glomerulonephritis, myocarditis, endocardial fibroelastosis, thrombocytopenia, cerebellar ataxia, transverse myelitis, ascending polyradiculitis, pancreatitis, oophoritis, and hearing impairment.In the absence of an immunization program, mumps typically occurs during childhood. Infection occurring among adults is more likely to be severe, and death resulting from mumps and its complications,although rare, occurs most often in adults. Mumps during the first trimester of pregnancy is associated with an increased rate of spontaneous abortion. Although mumps virus can cross the placenta, no evidence exists that this results in congenital malformation.

Chip-n'-Dale, pre-mumps

In layman’s terms, mumps virus:

  • attacks the salivary glands (swollen parotid glands = chipmunk cheeks), though that’s not always present
  • will cause central nervous system infection in about 1 out of 10 victims (anything from hellish headaches to encephalitis–serious inflammation of the lining of the brain)
  • increases the chances of a first trimester miscarriage
  • commonly causes swelling and inflammation of the testicles in adolescents and adults (just as bad as it sounds, fellas), and a few men will become sterile as a result
  • can cause a boatload of rare complications, including arthritis, loss of balance, heart and thyroid problems, inflammation of the ovaries, and hearing loss
  • every now and then kills someone

And in case you think mumps was a no-big-deal infection for our hardy ancestors, there’s this from the 1914 edition of Household Discoveries and Mrs. Curtis’s Cookbook (my Grandma Nell Sloan’s childcare bible; regular readers will be hearing a lot from Mrs. C in future posts). I’ve condensed it a bit:

Mumps is a glandular swelling in the angle between the jaw and the ear. It is a highly contagious but wholly unnecessary and preventable disease. The early symptoms are fever with pain below the ear on one or both sides. Within two days there is great and painful enlargement of the neck and side of the cheek. The swelling persists from seven to ten days, then gradually subsides. A second or third attack may occur and troublesome complications are common. It is always advisable to consult a physician.

Note: Mrs. Curtis does not call for the doctor very often.

I’ll talk about the reasons behind this outbreak and recent recurrences of other vaccine-preventable diseases in a future post.

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Flu shots and preschoolers

Making the world safe for older brothers.

Interesting study in today’s Science Times on flu shots and preschoolers. (Science Times is one of my favorite sites – new edition every Tuesday at NYTimes.com – click on ‘Science’ and it takes you there). Researchers at Boston Children’s Hospital compared preschooler emergency room visits for flu-like symptoms in Boston and Montreal, from 2000-2008 (big study: 114,657 ER visits). Reason for the study: the U.S. started recommending flu shots for 2-4 year-olds in 2006, and Canada didn’t require them until 2010. How big an impact did the U.S recommendation make?

Results? From 2006 on, ER visits for flu-like symptoms in 2- to 4 year-olds were 34% lower in Boston than Montreal. ER visits for 5- to 18 year-olds were 18% lower than in Montreal, too, probably because the older kids were protected by the younger kids’ flu shots. The Science Times blurb doesn’t mention hospitalization and complications (like pneumonia) but I assume those were lower, too.

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