Non-medical vaccination exemptions and wide misinformation on their efficiency are pulling America back into endemic measles outbreaks, a paper reports.

Back of female with measles.
Image credits Wellcome Trust.

The US took great pains (in the form of strict, nationwide vaccination campaigns) to eliminate measles back in 2000. Luckily, these efforts proved fruitful. Outbreaks did spring up here and there, mostly from people who travel to and from other countries, but they numbered a few dozens, upwards to a few hundred cases yearly. Which is a really small number. Overall, however, the measles virus was considered to no longer be endemic (present in the country) since the turn of the millennia.

But rejoice not! The US is slowly inching back to pre-2000 days, when the measles virus roamed free and deadly, researchers from the Stanford and Baylor College of Medicine warn. At the heart of the issue are non-medical vaccine exemptions and non-medical delays, coupled with wide public misinformation about vaccines.

A high toll

The two researchers, Nathan Lo, Bs. and Dr. Peter Hotez, MD., PhD., report that a 5% decrease in measles-mumps-and-rubella (MMR) vaccination rates among kids aged 2-11 would triple measles cases in the age group and end up draining the public health system some $2.1 million in additional costs. But wait, it gets even better/worse — ages 2-11 make up only about a third of measles cases in current outbreaks, but it was the only age interval the researchers had sufficient data to work with. They fully expect those numbers to become much higher once enough data to model “social mixing and immunization status of adults, teens, and infants under two” becomes available.

“The results of our study find substantial public health and economic consequences with even minor reductions in MMR coverage due to vaccine hesitancy and directly confront the notion that measles is no longer a threat in the United States,” they write.

The duo says they conducted this study out of concern for growing vaccine hesitancy and use of non-medical exemptions — both largely driven by shoddy data or outright lies pertaining to the safety of vaccines, and the downplaying of just how dangerous these diseases can be.

And measles is up there on the dangerous scale. The virus is ridiculously infectious, and can keep on floating in the air hours after a carrier coughed or sneezed. Those infected develop high fevers, skin rashes, inflamed eyes, and flu-like coughs and runny nose. About 30% of cases also come with highly desirable complications such as pneumonia, brain swelling, even blindness. While this does make it really simple to spot someone sick so you can stay away, carriers can spread the virus days before symptoms pop up.

Get your kid vaccinated!

So if the Eyeball Mk.1 we all come pre-equipped with can’t spot the danger, what do we do to stay safe? Well, we immunize the herd. So to speak. Basically, the idea behind herd immunity is to make such a large proportion of the population (around 90 to 95% of everybody) immune to the virus that it simply won’t be able to spread around effectively. There aren’t enough viable carriers to take spread it around.

It’s an all for one and one-starts-an-epidemic scenario. If immunity levels drop below that percentage, a single infected individual has a much higher chance of starting an outbreak — which, in turn, will have a much easier time infecting huge numbers of people. The bad news is that in many areas of the US, immunity levels are just shy of falling below that range, and vaccination rates still keep going down. Some 18 states allow parents to forego vaccination on the ground of personal beliefs, and almost all (except Mississippi and West Virginia) allow for religious and/or philosophical exceptions, according to the NCLS.

So, to get a feel for what these exceptions will do in the long run, the duo mathematically modeled the way measles spreads based on the virus’ known behavior, data on current vaccination rates from the CDC, and the “social mixing patterns” of kids aged 2-11. To get a rough estimate of the costs these outbreaks will take on the health system, they factored in stuff like medical staff wages, the cost of laboratory analyses, and money spent on outbreak surveillance. Each measles case, they estimate, costs about $20,000.

They then checked and calibrated their model based on data from past measles outbreaks from the US and UK. After they made sure their model works, they pushed up the vaccine exemption rate from 1% to 8% to see what would happen. Unsurprisingly, larger the exemption rates led to more cases and bigger outbreaks. Eliminating the exemptions however would take MMR coverage in the US to 95%, a very comfy percentage when talking about herd immunity.

In other words, when you chose not to vaccinate your kid, you’re putting both his health and that of others at risk. Stop believing what stupid stuff people say, believe, or write on shady websites over what your physician spent years learning in med school.

And most importantly, vaccinate your kids!

JAMA Pediatrics, 2017. DOI:10.1001/jamapediatrics.2017.1695 (About DOIs).

The paper “Public Health and Economic Consequences of Vaccine Hesitancy for Measles in the United States” has been published in the journal JAMA Pediatrics.