Denialism kills, anti-vaccine denialism kills children

measlesfrom Wikipedia

Widespread vaccine exemptions are messing with herd immunity
[Via Ars Technica]

Vaccines have been one of the most important public health interventions ever developed. As a new study notes, past analyses have estimated that the childhood immunization schedule prevents 42,000 deaths and 20 million cases of disease—and that’s only for the kids born in a single year. The estimated savings is currently at $14 billion a year.

But, despite the amazing benefits, immunization rates have been falling, driven by a fear that vaccines cause health problems such as autism. The autism risk has been both thoroughly debunked and the paper that originally suggested it turned out to be the product of an unethical, financially motivated individual. Despite this debunking, surveys show that a quarter of US parents think that vaccines can trigger autism, and rates of vaccination have continued to fall in many states. A new study looks at incoming kindergartners in California, and finds that the lack of vaccination is threatening herd immunity in some schools, and that some measures of risk have doubled in just three years.

California, like other states, has a mandatory immunization schedule, set as a requirement for children entering school. But California is also one of 20 states that allows a personal belief exemption, where parents can file notice that they have a personal issue with vaccines, and get their kids into schools despite a lack of vaccination. The rates of people asking for these exemptions has been slowly climbing, rising from half a percent in 1996 to 1.5 percent in 1997.


Herd immunity is what protects even unvaccinated people or those with weakened immune systems from getting the disease. The illness cannot spread rapidly enough to find those people, instead being topped by the large number of immunized people.

Herd immunity protects even those who do not have any immunity to the disease. It prevents its spread so they are very unlikely to become exposed. So, in a country where most everyone is immunized, it is okay for a small number to remain unvaccinated. The disease will not spread.

If we drop below herd immunity levels though, the disease can easily spread and it will mainly go after those without immunity. This will include the unvaccinated but also impact those who have weak immune systems such as the elderly and young.

In a place where herd immunity breaks down, the unvaccinated not only put themselves directly at risk, but also put at risk those who have no choice. Denialists put the community at risk.

In very contagious diseases, such as measles, about 94% of the population needs to be vaccinated in order to keep the disease from spreading.

But, what happens when anti-vaccination denialists  cluster in the same community or school? The herd immunity levels drop below the necessary levels and there is an outbreak, one that can kill.

In California, the average student is in a school where almost 16% of the student’s have an exemption. In some places in California, almost half the students were exempt meaning they had no protection at all from herd immunity. They might as well exist in the world of the 40s as far as communicable disease relates to them.

This places the average student in a community where the ability of almost EVERY communicable disease to spread is no longer hampered much by the herd effect. What happens when pertussis breaks out – as seen in Washington – or even polio makes a comeback? All because these people selfishly refuse to vaccinate their children

And the students that will most likely get these illnesses will be those who are not vaccinated, such as the denialist students. But we will also see infants die as well as elderly.

It is bad enough that denialist parents are putting their own children at risk – in some schools the chances of getting one of these communicable diseases is essentially no different than it was in the days before vaccination. They are also putting others at risk. 

I wonder how many pregnant women get rubella because of the unvaccinated children of denialist parents? Studies show that over 30% of pregnant women are susceptible to rubella, rubeola and mumps with 10% susceptible to rubella. Think of that, 10% of all pregnancies in some areas of California are in danger of miscarriage or birth defects because of the loss of herd immunity.

I think that if someone wants to have an exemption for their child, fine but require all exempted children to attend the same school and try to raise the herd immunity levels at the other schools.

Having a school with no immunity or half the students makes no difference for the spread of the disease – there is little herd immunity in either case. So put all the kids in one place and let the rest of us have schools that permit herd immunity to protect the community.

No vaccination, no herd immunity protection. Deal with it.

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