Measles Facts and Fiction

Fact: the news media is not trained in epidemiology.

Another fact: TV shows (like, say, Law and Order) are not scholarly sources of information on anything.

There are a lot of misconceptions circulating about measles and the state of measles here in the United States. Personally, I feel like the media bears some responsibility as journalists and TV shows present a series of half-truths or outright wrong information to the public under the guise of telling the public the facts. So I’d like to take a moment and clarify a few things on measles with information from the CDC, WHO and some medical and science journals…

Measles is coming back at rates never seen since the introduction of the measles vaccineFalseMeasles has always been cyclical in nature with more cases in some years than others. If you look at the CDC’s data on reported cases of measles and deaths from measles from 1950 to 2013, you’ll see that some years have been higher and others lower for measles, but reported cases of measles have been on a continual decline since 1967. (1968 was when the Edmonsten-Enders strain vaccine that is currently in use was introduced. An earlier version was developed in 1963, but not as widely adopted.)

Between 1950 and 1963, reported cases of measles ranged from a low of 319,124 in 1950 to a high of 763,094 in 1958. The death rate usually averaged about 1 in 1,000, but fluctuated some. For example in 1958, there were 763,094 measles cases reported with 552 deaths, a rate of 7 deaths per every 10,000 cases or .7 deaths for every 1,000 cases.

The most dramatic drop-off happened between 1966-1967 (204,136 to 62,705). The next big drop occurred between 1992 and 1993 (2,237 to 312). But even after the MMR vaccine was widely adopted, there were still ups and downs. For example in 1970 there were 47,351 reported cases of measles and there were 75,290 reported cases of measles in 1971. In 1993 there were 312 reported cases of measles and 963 reported cases of measles in 1994. In 1995, it dropped back down to 309 reported cases of measles.

Rates of reported measles cases between 2007 to 2013 are as follows: 2007-43, 2008-140, 2009-71, 2010- 63, 2011- 220, 2012-55, 2013-187, For 2014 through 2016: 2014- 667, 2015-188 (that includes the Disneyland measles outbreak), 2016- 70. (Note- the 2016 data is as of December 31, 2016. This number could be subject to change if new information comes in, though it hasn’t changed yet.)

I freely acknowledge that I am not a doctor, and the highest level of math I have taken is only Trigonometry, but it’s pretty clear that there is a big difference between 763,094 and 70 (or even 667). Reported rates of measles are nowhere near what they were in the pre-vaccine era.

People are dying of measles for the first time since the pre-vaccine era.- False. Again, refer to the chart from the CDC’s Pink Book on reported cases of measles. Measles deaths, though much rarer, continued through the 20th century with a few into the 21st century. According to the CDC’s numbers reported, the last measles death occurred in 2003.

Vaccine refusal is on the rise.- True and False. Yes, this is kind of a trick question. The all time high for vaccination coverage for school age children (ages 5-6 years) appears to be 95% as a national average between the years of 1980 and 1998, based on the CDC’s Weekly Morbidity and Mortality Report dated April 2, 1999.  In 2016, the national average for MMR coverage for children ages 5-6 years was 94.6% according to the October 7, 2016 Morbidity and Mortality Weekly Report. In 1997, the coverage rate of MMR for children ages 19-35 months was 90%. In 2015, the rate of coverage for MMR was 91.9% for one or more doses. So yes, coverage is on the decline by a small amount for school age children, but it’s actually slightly on the rise for younger children. Now if the charts posted by Harvard and PBS are accurate, the threshold for herd immunity for measles is between 83% and 94%, so based on current numbers for school age children at least, we haven’t fallen below the level of herd immunity. At these levels, even Colorado is still within herd immunity limits. (The above cited MMWR says that Colorado has the lowest coverage in the nation for MMR at 87.1% for the 2015-2016 school year. But that’s actually up from 86.9% in the 2014-2015 school year ).  The overwhelming majority of Americans still vaccinate.

Unvaccinated people spread measles at Disneyland. False- based on the information currently available According to the CDC, no source was identified for the Disneyland measles outbreak.

You can be sure you don’t have measles if you’re vaccinatedFalse. According to the CDC, two doses of measles vaccine is 97% effective at preventing measles. Considering that the average primary school enrollment in the US is 450.8 students, there is a chance that someone could still carry measles from vaccine failure even at a fully vaccinated school. Another issue is waning immunity. A 2008 study from Finland published in the Journal of Infectious Diseases found that efficacy was still high for individuals who had received a second dose of MMR after 20 years, but that measles immunity was no longer present in 5% of the individuals in the study. There is also modified measles- a form of measles that doesn’t carry the classical rash and affects vaccinated individuals. Data is scarce on this phenomenon. A few cases have been studied, including two physicians as described in the 2011 Journal of Infectious Diseases. The tricky thing about modified measles is that it presents with very generalized symptoms like coughing and a runny nose, which is why some researchers suspect it may be very underreported.  The risk of transmission seems to be low, but again actual data is scarce. What happens if a doctor with modified measles treats a patient with HIV or who is undergoing chemotherapy? If you get modified measles, how long will the immunity last? If you are a woman and you get modified measles, can you pass the antibodies to your baby through breastfeeding for passive immunity and how long would that last, hypothetically speaking? We don’t have any data on these scenarios at the moment, though hopefully we will soon as health officials become more aware of modified measles.

Vaccinated people don’t spread measles.- False. It is possible for a vaccinated individual to be part of the chain of transmission. In 2011, the first documented case of measles transmission from a twice-vaccinated individual with documented secondary vaccine failure occurred and was subsequently published in Clinical Infectious Diseases in 2014.

Mississippi and West Virginia don’t allow religious or philosophical exemptions. They are models of public health and an example for other states.- False. This is probably one of my biggest public health pet peeves with the media these days. Yes, Mississippi has low measles rates, but that’s about it. Mississippi has some of the highest rates of diabetes, heart disease, infant mortality and tobacco use of any state in the nation. Mortality is very high there. Poverty is rampant and (plug for breastfeeding coming): breastfeeding rates are extremely low. (And mandatory health insurance hasn’t changed anything, but that’s another soapbox for another day.) Ditto for West Virginia. In Mississippi, 4,700 people die from the effects of tobacco use every year, that’s 8.5 times the deaths from measles in the entire country in 1958, which was a high year for measles deaths.

West Virginia is facing a drug problem that has literally been called an epidemic with overdoses accounting for a jaw-dropping  41.5 deaths per 100,000– the highest in the nation. Public health records from 1956 say of the death rate from measles: “The death rate for measles has been below 1 per 100,000 population in the last decade as compared with rates between 7 and 13 per 100,000 in the early part of the century.” That means if we were to take the high rates of measles deaths from the early twentieth-century and triple it, the death rate from overdoses in West Virginia would still be slightly higher; that’s how out-of-control the drug use problem has gotten in West Virginia.

Good grief, Mississippi and  West Virginia frequently swap for 49th and 50th place in health rankings. The media coverage of Mississippi’s and West Virginia’s vaccine exemption policies ignores the astounding health problems the residents of these states face. The focus on vaccine exemptions in schools is also deceptive because West Virginia has some of the lowest rates of coverage for children ages 19-35 months with only 67% receiving the full vaccination schedule in 2011. “Medical exemptions only” policies are not some sort of magic pill to make morbidity and mortality go away and people need to be aware of the bigger picture.

Breastfeeding won’t protect your baby from measles.- True and False. Maternal measles antibodies do grant protection from measles to breastfeeding babies, but that immunity does wane over a period of months. One study from Belgium found that by nine months measles antibodies were no longer at a threshold of immunity in both mothers who had immunity from vaccination and those who had natural immunity. (Though mothers with natural immunity had higher levels of antibodies that they passed to their babies for longer than those with vaccine acquired immunity.)

There were no measles cases in the US because it was eradicated and now it’s back. False. Take a look at the CDC’s data sheet on reported cases of measles and measles deaths and you’ll see that there have been cases of measles every year. Measles was declared eliminated from the United States in 2000. From the Journal of the American Medical Association: “Elimination does not imply zero cases because some cases will continue to occur owing to international importation and limited local transmission.” Measles elimination is defined by the CDC as “the absence of continuous disease transmission for 12 months or more in a specific geographic area. Measles is no longer endemic (constantly present) in the United States.” (Confused about elimination vs. eradication? This is an awesome article from NPR that explains the difference really well.)

The measles vaccine ensures that your child won’t develop encephalitis or pneumonia. –False. Pneumonia from measles was the most common cause of death from the disease. (Pneumonia can result from several different infections.) Encephalitis can also result from many different kinds of infections. In fact, a recent study from the UK found that while encephalitis from measles and mumps have decreased, encephalitis from other sources (both known and unknown) have increased. Pneumonia still accounts for 15.9 deaths per 100,000 in the United States. We still need to be vigilant about these conditions.

A rash and high fever are dead giveaways that it’s measles.- False. There are clinical cases and laboratory confirmed cases. Clinical cases meet the criteria of symptoms history of fever, rash for three or more days, and either cough, coryza (runny nose) or conjunctivitis (pink eye) and (within the US) a history of recent international travel. Laboratory confirmed cases show confirmation from laboratory cases like IgM antibodies against the disease. But clinical diagnosis has its limits. For example, a study on 105 children in Zimbabwe showed that while 91% met the clinical criteria, only 75% had antibody levels consistent with a current measles infection based on laboratory testing. This is an older study, but interesting nonetheless as it found that (at least in 1995) only 11% of measles cases in the UK were validated by laboratory testing and that when laboratory testing was used many cases of measles were actually a condition called roseola infantum- a form of human herpesvirus-6.  A little more recent study (2003) from Brazil confirmed that human herpesvirus-6 can be mistaken for measles when diagnosis focuses too much on the rash as a symptom instead of using laboratory testing.

If you get measles, there is nothing you can do to prevent complications except hope for the best.- False. The role of Vitamin A in preventing serious measles complications (especially pneumonia) has been well-documented in health literature. The World Health Organization recommends greater access to vitamin A rich foods, especially in areas with malnutrition for this reason. An outbreak in India showed that an astounding 32.76% of measles cases in an outbreak had been vaccinated for measles, but the highest rates occurred among children with vitamin A deficiency. Vitamin A deficiency could possibly be a contributing factor to the death toll in the recent Romania outbreak as malnutrition continues to plague Romania.

Measles is a deadly disease for children. True and False. Measles can cause death in children, but children under 5 and adults have a higher rate of complications. Adults are especially at risk for a condition called subacute sclerosing panencephalitis, which may be why fatality rates have increased. (For example 2 deaths out of 100 measles cases in 1999, other years had similar rates.) As rates of vaccination have increased in school age children, the disease has more opportunity to infect adults, especially since fewer people have natural immunity. Interestingly, this was a concern voiced by some during the 1960’s when the measles vaccine schedule was being discussed, but many officials felt that it would be best to vaccinate children. (This is a fascinating read. It’s from the Netherlands and used archived public health documents to understand what issues were at play as Dutch health officials were deciding on the vaccine schedule, but it discusses what was going on in the US and UK as well and how their policies influenced other countries. I highly recommend it.)





Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: