The Neighborhood Effects of Vaccines

By Deborah M. Figart

Recently I had a conversation with my doctor about the new measles outbreak in the United States. Then I went to check my immunization record. This paper record is a small, decades-old 2×3 inch booklet kept by my mother in the 1960s. I am surprised you can still read the yellowed pages. It records my immunizations by type, date, year, and doctor. My mother also logged when I had the chicken pox. She even noted when I had my tonsillectomy and my first X-ray—of the skull when I fell straight down on my forehead while sledding one winter.

Measles was eliminated in the United States in 2000. But in an open country, international travelers and tourists can bring in the disease. The recent outbreak as a result of exposure at the Disneyland resort in California over the last Christmas and New Years holiday has multiplied. The Centers for Disease Control and Prevention (CDC) reported 644 cases in 27 states 2014, the greatest number since 2000. From January 1 to February 13, 2015, there have been 141 reported cases thus far in 17 states and Washington, DC, including New Jersey. We are on track for a record number of measles cases in 2015, a large step backward from 2000 when we eliminated the disease in our homeland. Starting with one case of a potent virus leads to many; the rise is easily predicted in public health models. This current eruption has adults reviewing their medical records, reading over the government’s vaccination guidelines, and checking with their doctor.

The spike in measles has also reopened debate between public health officials and medical experts who seek to control the disease and opponents of vaccines. The Centers for Disease Control and the American Academy of Pediatrics are on one side, according to Parents magazine. Opposition can be found in the United Kingdom and the United States among autism advocacy groups, some professional chiropractors, and local or state groups such as My Kids, My Choice in New York. In medical circles, the debate has long been settled through evidence of the worth of vaccines. Still others remain unconvinced.

According to the U.S. Department of Health and Human Services (HHS), people born before 1957 in the United States are generally considered immune to measles and mumps. In 1963, I was vaccinated for measles; there was no vaccine for mumps or rubella at the time (also known as the German measles). Today the three vaccinations are packed together and known as MMR. The MMR vaccine given to children in the U.S. since 1971 has been highly effective. But there a period from 1963-1967 with competing measles vaccines. Within this window, some received a live vaccine and others received an inactivated vaccine which was later pulled from the U.S. market in 1967. I was in that window.

That brings me back to my doctor. She tells me that the HHS guidelines state that persons who received inactivated (killed) measles vaccine or measles vaccine of unknown type during 1963–1967 should be revaccinated with two doses of MMR vaccine. I opted to be revaccinated as an adult, which only required one shot instead of the two given to children.

I am not a medical doctor. I must rely on the medical experts to help educate me on the safety and benefits of (largely) compulsory vaccination. But I have a doctorate in economics. It is easy for me to see the benefits through the eyes of an economist: it has to do with externalities.

Many of our decisions and actions affect other people. Economists refer to theses effects as positive or negative externalities. The term “externalities” means that the activity or product affects someone who is neither the buyer nor the seller, someone outside or external to the economic transaction.

Cigarette smoking obviously has negative externalities because second-hand smoke affects nonsmokers, but also because a higher incidence of illness tends to push up health care and insurance premiums for everyone. Society taxes cigarettes heavily to offset these costs and to discourage young people from smoking. When the housing bubble burst in 2008, we found that vacated and foreclosed homes lowered property values for others in the same neighborhoods, even if they kept up with their payments and were not overly in debt. So the decision to issue risky mortgages affected people with no voice in the process. That’s why another term for externalities is “neighborhood effects.”

Externalities can be good things too. We ask the taxpayers to shoulder part of the costs of public colleges and universities because the benefits of an educated work force and citizenry go beyond the individuals attending college. Public transportation helps those who take the bus, but also alleviates traffic for those who still drive. These are positive externalities.

Vaccines have positive neighborhood effects as well. No vaccine is 100% effective. Therefore, you are better protected if your neighbors are not carrying the disease. That happens if we are all vaccinated. So … it’s the neighborly thing to do.