Measles is a horrible disease that contributed to the downfall that had been declared dead in the US, wiped out by immunization, but it has reappeared. A lot of the blame goes to folks who refuse to vaccinate: anti-vaxers in the popular press. The Center for Disease Control is doing its best to promote to stop the anti-vaxers, and promote vaccination for all, but in doing so, I find they present the risks of measles worse than they are. While I’m sympathetic to the goal, I’m not a fan of bending the truth. Lies hurt the people who speak them and the ones who believe them, and they can hurt the health of immune-compromized children who are pushed to vaccinate. You will see my arguments below.

The CDC’s most-used value for the mortality rate for measles is 0.3%. It appears, for example, in line two of the following table from Orenstein et al., 2004. This table also includes measles-caused complications, broken down by type and patient age; read the full article here.

Measles complications, death rates, US, 1987-2000, CDC, Orenstein et. al. 2004.

The 0.3% average mortality rate seems more in tune with the 1800s than today. Similarly, note that the risk of measles-associated encephalitis is given as 10.1%, higher than the risk of measles-diarrhea, 8.2%. Do 10.1% of measles cases today produce encephalitis, a horrible, brain-swelling disease that often causes death. Basically everyone in the 1950s and early 60s got measles (I got it twice), but there were only 1000 cases of encephalitis per year. None of my classmates got encephalitis, and none died. How is this possible; it was the era before antibiotics. Even Orenstein et. al comment that their measles mortality rates appear to be far higher today than in the 1940s and 50s. The article explains that the increase to 3 per thousand, “is most likely due to more complete reporting of measles as a cause of death, HIV infections, and a higher proportion of cases among preschool-aged children and adults.”

A far more likely explanation is that the CDC value is wrong. That the measles cases that were reported and certified as such are the ones that are the most severe. There were about 450 measles deaths per year in the 1940s and 1950s, and 408 in 1962, the last year before the MMR vaccine was developed and by Dr. Hilleman of Merck (a great man of science, forgotten). In the last two decades there were some 2000 measles cases reported US cases but only one measles death. A significant decline in cases, but the ratio does not support the CDC’s death rate. For a better estimate, I propose to divide the total number of measles deaths in 1962 by the average birth rate in the late 1950s. That is to say, I propose to divide 408 by the 4.3 million births per year. From this, I calculate a mortality rate just under 0.01% in 1962, That’s 1/30th the CDC number, and medicine has improved since 1962.

I suspect that the CDC inflates the mortality numbers, in part by cherry-picking its years. It inflates them further by treating “reported measles cases.” as if they were all measles cases. I suspect that the reported cases in these years were mainly the very severe ones. Mild case measles clears up before being reported or certified as measles. This seems the only normal explanation for why 10.1% of cases include encephalitis, and only 8.2% diarrhea. It’s why the CDC’s mortality numbers suggest that, despite antibiotics, our death rate has gone up by a factor of 30 since 1962.

Consider the experience of people who lived in the early 60s. Most children of my era went to public elementary schools with some 1000 other students, all of whom got measles. By the CDC’s mortality number, we should have seen three measles deaths per school, and 101 cases of encephalitis. In reality, if there had been one death in my school it would have been big news, and it’s impossible that 10% of my classmates got encephalitis. Instead, in those years, only 48,000 people were hospitalized per year for measles, and 1,000 of these suffered encephalitis (CDC numbers, reported here).

To see if vaccination is a good idea, lets now consider the risk of vaccination. The CDC reports their vaccine “is virtually risk free”, but what does risk-free mean? A British study finds vaccination-caused neurological damage in 1/365,000 MMR vaccinations, a rate of 0.00027%, with a small fraction leading to death. These problems are mostly found in immunocompromised patients. I will now estimate the neurological risk for actual measles based on the ratio of encephalitis to births, as before using the average birth rate as my estimate for measles cases; 1000/4,300,000 = 0.023%. This is far lower than the risk the CDC reports, and more in line with experience.

The risk for neurological damage from measles that I calculate is 86 times higher risk than the neurological risk from vaccination, suggesting vaccination is a very good thing, on average: The vast majority of people should get vaccinated. But for people with a weakened immune system, my calculations suggest it is worthwhile to not immunize at 12 months as doctors recommend. The main cause of vaccination death is encephalitis, but this only happens in patients with weakened immune systems. If your child’s immune system is weakened, even by a cold, I’d suggest you wait 1-3 months, and would hope that your doctor would concur. If your child has AIDS, ALS, Lupus, or any other, long-term immune problem, you should not vaccinate at all. Not vaccinating your immune-weakened child will weaken the herd immunity, but will protect your child.

We live in a country with significant herd immunity: Even if there were a measles outbreak, it is unlikely there would be 500 cases at one time, and your child’s chance of running into one of them in the next month is very small assuming that you don’t take your child to Disneyland, or to visit relatives from abroad. Also, don’t hang out with anti-vaxers if you are not vaccinated. Associating with anti-vaxers will dramatically increase your child’s risk of infection.

As for autism: there appears to be no autism advantage to pushing off vaccination. Signs of autism typically appear around 12 months, the same age that most children receive their first-stage MMR shot, so some people came to associate the two. Parents who push-off vaccination do not push-off the child’s chance of developing autism, they just increase the chance their child will get measles, and that their child will infect others. Schools are right to bar such children, IMHO.

I’ve noticed that, with health care in, particular, there is a tendency for researchers to mangle statistics so that good things seem better than they are. Health food: is not necessarily so healthy as they say; nor is weight loss. Bicycle helmets: ditto. Sometimes this bleeds over to outright lies. Generic modified grains were branded as cancer-causing based on outright lies and  missionary zeal. I feel that I help a bit, in part by countering individual white lies; in part by teaching folks how to better read statistic arguments. If you are a researcher, I strongly suggest you do not set up your research with a hypothesis so that only one outcome will be publishable or acceptable. Here’s how.

Robert E. Buxbaum, December 9, 2018.