Did you know August is National Immunization Awareness Month, which is sponsored by the National Public Health Information Coalition (NPHIC)?
Vaccines have played a crucial role in advancing public health throughout the world and have come a long way since Edward Jenner first inoculated a small boy with cowpox on May 14, 1796 in an experiment to protect against smallpox.
One could argue that vaccines, along with clean water and a steady, safe food supply, have done more to extend the average human life expectancy than any recent advances in medicine. This has been eloquently discussed in detail by Laura Helmuth in Slate magazine: “Why are you not dead yet?” The primary principle of vaccines is to induce an immune response in enough of the population to provide “herd immunity.” This affords those who are not eligible for certain vaccines some degree of protection because the spread of contagious disease is contained by those who are vaccinated.
The terms vaccine and vaccinate actually come from the Latin word for cowpox — vaccinia. Prior to Jenner’s work, 400,000 people died annually in 18th century Europe from small pox, and one third of survivors went blind (Ann Intern Med. 1997;127(8 Pt 1):635–642). Through vaccine technology, this once feared infection has been completely eradicated in the general population.
Today, in the United States, there are vaccines available to combat 25 different diseases ranging from anthrax to influenza to Japanese Encephalitis virus. The vaccines included in the recommend vaccine schedule for children and adolescents have dramatically changed the lives of Americans that we truly take for granted today.
Prior to the introduction of the measles vaccine, an average of 542,000 cases were reported annually in the last half of the 1950s with an average of 450 measles related deaths per 1000 reported cases (National Center for Health Statistics).
In the 1940s and early 1950s, an average of 35,000 cases of polio were reported yearly in the U.S. Following the introduction of the Salk inactivated poliovirus vaccine (IPV) in 1955, the number of cases dropped to 2,100 in 1957 and 61 cases in 1965.
Vaccines have not been without controversy, particularly in the last two decades. Much of that focus has been on vaccine safety. Of course, safety should be on the forefront of every parent’s mind when it comes to his or her child. However, when compared to the risks and burden of the actual diseases, the risk of vaccines is rather small. Being educated about the actual statistical data provides some context.
- Risk of dying while riding a bicycle: 2.31/1,000,000 persons (2012 NHTSA)
- Risk of lightning strike: 1/1,190,000 persons per year (NOAA)
- Risk of drowning: 12.4/1,000,000 persons (CDC)
- Risk of encephalitis with measles infection: 1/1,000 person (CDC)
- Risk of encephalitis with measles vaccine: 1/1,000,000 persons (CDC)
- Risk of anaphylaxis with inactivated influenza vaccine: 7/10,000,000 (WHO)
An individual is 1000 times more likely to develop encephalitis from an actual measles infection than from the vaccine itself. Meanwhile one is twice as likely to die while riding a bicycle than developing encephalitis from the measles vaccine.
For more information on vaccines, their risks, and preservatives used, visit the CDC web page on vaccines.
Bryan Youree, MD, is an infectious disease physician with the Tarrant County Infectious Disease Associates in Fort Worth, Texas. He has worked in the infectious disease field for 10 years. He attended Baylor College of Medicine and completed his post-graduate training at Vanderbilt University Medical Center. He served on faculty there before joining the Fort Worth practice.