By Constance Caldwell, M.D.
It is almost time for kindergarten enrollment, and a number of vaccines are required for entry. The same goes for child care. For some, it begs the question: Why do we bother to vaccinate our children against a variety of illnesses, and why is it required?
The near-elimination of many previously common diseases by vaccination efforts is one of the greatest public health achievements of the past century. As a result, many parents have never seen a child with measles or whooping cough. Regrettably, and mistakenly, some may think “those illnesses are a thing of the past; they just belong in the history books.” Others may think “my child won’t get sick because all the other children who are vaccinated will protect my child.”
The parent who thinks measles or whooping cough belong only in the history books is, unfortunately, incorrect. There were more than 2,300 cases of pertussis (whooping cough) reported in California in 2013. Already this year, there has been one death reported in California. Not surprising, the counties with the highest percentage of unvaccinated children are the counties with the highest rates of pertussis.
How about measles? The last large outbreak of measles in the United States was between 1989 and 1991, during which time there were 17,000 cases and 70 deaths in California. In 2014, about 20 cases of measles have been reported in California. Several other states are also seeing measles cases.
This brings us to the parents who think other vaccinated children will protect their children. There is indeed such a thing as “herd immunity.” If most people (the herd) are vaccinated, it is unlikely that there will be an outbreak of the disease, and a reduced risk for the unvaccinated of acquiring the disease.
However, there is a major caveat to the concept of “herd immunity,” when applied to whooping cough and measles. For both of these diseases, approximately 95 percent of people need to be vaccinated to prevent disease outbreaks.
Unfortunately, vaccination rates among children entering California kindergartens have dropped precipitously since 2000. Many counties are seeing more than 10 percent of their entering students unvaccinated, and a few have more than 20 percent unvaccinated. Yolo County saw almost 9 percent of its entering kindergartners in 2012 unvaccinated or incompletely vaccinated. This puts all of us at risk for outbreaks of whooping cough and measles.
If a child gets whooping cough or measles, he could become very ill or even die. The child will lose many school days and the parents will lose many work days. If your child is merely exposed to one of these illnesses, he could be excluded from school for several weeks to prevent spread of the disease to other children.
So, please, please, vaccinate your children to help keep them, your family and our community healthy.
— Constance Caldwell, M.D., is Yolo County’s health officer.