A Rash of Measles Cases in the United States

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February 1, 2015

Measles was thought to be virtually eliminated in the U.S., reaching an all-time low of 37 cases in 2004. However, it’s in the news again. Dr. Thu Tran’s father-in-law, Dr. Sam Katz, developed the vaccine in the 1960s and infection rates decreased steadily. Unfortunately, a later-discredited study linking vaccines to autism caused some parents to withhold these vaccines from their children.  The number of measles cases in the U.S. rose to 644 by 2014.  There have been cases in communities that have a lower vaccination rate, including in California and within an Amish community in Ohio.

In prior years, most of the cases in the U.S. involved people who had recently been in other countries and then spread within unvaccinated areas.  In 2015, however, most of the 90 or so cases reported so far were acquired during a visit to the Disney park in California, or from secondary exposure by being around the Disney visitors while they were contagious but before they were aware of their illness. The majority of those affected were not immunized or were incompletely immunized.

The measles virus is spread by respiratory droplets and can remain infectious for up to 2 hours. A person is contagious starting about 4 days prior to the rash outbreak, and therefore may be around many people before they are aware that they are ill. The common symptoms are rash starting on the face and proceeding down the body, cough, runny nose, eye symptoms, and fever. It can be very serious especially in adults, leading to ear infections, pneumonia, seizures, and rarely brain damage or death. It is highly infectious, so that 90% of people exposed who are not immune may become ill.

Immune status is achieved either through having the illness or by getting the MMR (measles, mumps and rubella [German measles]) vaccine. The approved vaccination schedule for pediatrics is one dose at 12-15 months and one between 4 and 6 years old. After two doses of the vaccine, individuals are 95-99% likely to be protected from the virus. The 2015 update reflects the increased incidence of infection, with an accelerated option for children who are traveling abroad.

According to the CDC, adults born before 1957 are generally considered to be immune to measles and mumps. Those over 18 who were born after 1956 should get a dose of MMR unless they have a contraindication (see below), have been fully vaccinated or have blood tests showing immunity (antibodies to measles).

Adults at high risk because of where they live, work, travel or attend school should get 2 doses at least 4 weeks apart unless they have similar proof of immunity.

If you are unsure whether you need the vaccine, you can check with your doctor about your immune status and relative risk. As with any vaccine, side effects are possible, including local reactions in the arm as well as fever, headache, etc. Those who have had a reaction to this vaccine, are allergic to neomycin, or have a low platelet count should also avoid it.

This is an attenuated live vaccine, meaning that those with HIV or other immune disorders, or those who have been ill recently, those receiving chemotherapy, steroids or transfusions or who are pregnant should not get the vaccine. Women who are planning to become pregnant often have their immune titers to MMR checked prior to pregnancy so they can be appropriately immunized ahead of time.

We can see that the reason measles has become rare is from broad population use of the vaccine. As vaccination rates decrease, the virus has a chance to be spread from person to person. As a public health issue, each person should be able to declare – the buck stops here!


http://www.cdc.gov/vaccines/hcp/vis/vis-statements/mmr.html – 2015 schedule just approved by the American Academy of Pediatrics.

http://www.cdc.gov/vaccines/schedules/hcp/imz/adult.html – adult immunization recommendations

http://www.cdc.gov/measles/images/measles-cases-616px.jpg – incidence of measles in US

http://www.cdph.ca.gov/Pages/NR15-008.aspx – California Dept of Public Health