Study: Vaccine refusal is fueling the spread of potentially deadly diseases

A recent study finds vaccine refusals have, indeed, accelerated the resurgence of whooping cough and measles here in the U.S. The findings are making headlines around the country — and comment sections are filling up with vitriol from anti-vaxxers — but it would feel amiss not to highlight the study on a blog dedicated to public health. But first, let’s remind ourselves of the pain and suffering that preceded vaccines.

Here’s a brief snapshot of what life was like before vaccines and what it’s currently like for people without access to these life-saving medicines:

Whooping cough (pertussis): Before the availability of a vaccine in the 1940s, whooping cough was a common cause of illness and major cause of death for children. Between 1940 and 1945, about 175,000 cases of whooping cough occurred every year. After the vaccine was introduced, disease incidence dropped more than 80 percent. Still, between 2000 and 2014, the disease caused 277 deaths in the U.S., mostly among babies too young to be vaccinated. In the developing world in 2008, according to the World Health Organization (WHO), 195,000 children died from whooping cough.

Rubella: In 1969, nearly 58,000 cases of rubella were reported in the U.S. The vaccine was introduced in 1969 and by 1983, there were less than 1,000 cases annually. In 2003, there were just seven U.S. cases. (In 1964-1965, an epidemic of rubella swept through the nation, sickening more than 12 million people, killing 2,000 infants and causing 11,000 miscarriages.) Globally, more than 100,000 babies are born every year with congenital rubella syndrome, which is associated with cataracts, congenital heart disease, hearing impairment and developmental delays.

Measles: Before a measles vaccine, nearly all Americans got measles and thousands ended up in the hospital every year with serious complications. Before 1963, about 500,000 U.S. measles cases and 500 deaths happened every year. (However, many years before major advancements in medical care, the fatality rate was much worse. For example, in 1920, more than 7,000 Americans died from measles.) Post-1963, when the vaccine came on the scene, measles cases declined by more than 95 percent. Worldwide, measles remains a leading cause of death for young children. However, researchers estimate that between 2000-2013, the measles vaccine prevented more than 17 million deaths worldwide.

Diphtheria: Diphtheria used to be a major cause of illness and death in the U.S., especially for children. For example, in 1920, 147,991 diphtheria cases were reported in the U.S. and 13,170 people died. Since 2004, just one case of diphtheria has been reported to the Centers for Disease Control and Prevention. In 2014, WHO reported more than 7,000 cases of diphtheria globally, though it’s likely that many cases are going unreported.

Smallpox: Let’s make it easy: vaccines won. You don’t have to worry about catching, dying or going blind from smallpox anymore. (Please send thank-you notes to your local public health department.)

Okay, now that I’ve got that out of my system, back to the new study. Published this month in JAMA, the study found that a substantial number of U.S. measles cases that happened after 2000 — when the disease was declared eliminated in the U.S. — occurred among patients who were left purposefully unvaccinated (i.e. vaccine refusal). They also found that vaccine refusal was associated with an increased risk for whooping cough, though waning immunity seems to be contributing as well.

To conduct the study, researchers combed through the scientific literature for reports of measles outbreaks between 2000 and 2015 and for whooping cough outbreaks since 1977, when incidence of that disease reached a record low. They identified more than 1,400 measles cases since 2000, of which more than 56 percent occurred in children whose parents refused vaccination. Among the five largest statewide whooping cough epidemics identified, between 24 percent and 45 percent of patients were unvaccinated or undervaccinated.

Of the 970 measles cases with accompanying vaccination data, 574 cases were unvaccinated despite being eligible to receive the immunization and 405 cases had nonmedical vaccine exemptions, such as religious or philosophical opposition to vaccines. In eight of 12 whooping cough outbreaks from nine studies that included vaccination data, the researchers found that 59 percent to 93 percent of unvaccinated patients were left unvaccinated on purpose. However, the study also noted that epidemics of whooping cough occurred in vaccinated populations too, which highlights the issue of waning immunity.

The study authors concluded that the “phenomenon of vaccine refusal was associated with an increased risk for measles among people who refuse vaccines and among fully vaccinated individuals. Although pertussis resurgence has been attributed to waning immunity and other factors, vaccine refusal was still associated with an increased risk for pertussis in some populations.”

In his official blog as director of the National Institutes of Health, Francis Collins wrote in response to the vaccine refusal study:

Parents have a responsibility not only to their own children, but to their communities — it’s only by achieving a very high level of population immunity that outbreaks can be prevented. Vaccination is particularly crucial for children with cancer and other diseases that cause immunosuppression. They cannot be vaccinated safely, but are at high risk of severe consequences if they are infected — and, thus, they depend on the community’s so-called “herd immunity” for protection against a potentially fatal illness.

According to CDC, though measles was declared eliminated in the U.S. in 2000, the contagious disease is making an unfortunate comeback, spiking to 667 cases in 2014. As for highly contagious whooping cough, the disease reached a recent high in 2012 with more than 48,000 documented cases — that’s the largest number of reported cases since 1955.

To request a copy of the vaccine refusal study, visit JAMA.

Kim Krisberg is a freelance public health writer living in Austin, Texas, and has been writing about public health for nearly 15 years.