Contagious Diseases in the U.S. from 1888 to 2011

In November 2013, Donald Burke and coworkers at the University of Pittsburgh published an interesting study. The authors wanted to determine the impact of vaccines in the United States. They obtained weekly surveillance data published in the journal Morbidity and Mortality Weekly Report between 1888 and 2011. They used the year that a vaccine was licensed as the cutoff year to separate the pre-vaccine from post-vaccine period, realizing that uptake would be variable. They then multiplied the median weekly incidence rates from pre-vaccine years with population estimates for the post-vaccine years.

The authors estimated that about 103 million cases of disease had been prevented by vaccination since 1924. Of these hypothetical cases, about 26 million cases were prevented in the most recent decade included in the study (2002-2011). The disease with the most cases prevented was diphtheria (40 million cases), owing primarily to the fact that diphtheria had the second highest pre-vaccination incidence rate (237 cases per 100,000 population year) and the longest standing vaccine program. Second was measles (35 million cases), which had the highest disease incidence (318 cases per 100,000 population year).

Of interest, the disease with the most rapid decrease in the number of reported cases was measles (22% decrease each year post-vaccination). Rubella and polio were next, with annual decreases of 16% and 15%, respectively.

Perhaps more than any other, this study shows the incredible power and impact of America’s vaccine program.

Which vaccine has saved the most infant lives during the last 50 years?

Fifty years ago, a program called the Expanded Programme on Immunization (EPI) was started with a goal of vaccinating all children around the globe against several vaccine-preventable diseases, including diphtheria, measles, pertussis, polio, tetanus, tuberculosis and smallpox. Of these, smallpox has since been eradicated, meaning it no longer exists, so it can no longer cause illness. The other six diseases continue to infect people throughout the world.

However, on this 50th anniversary of EPI, there is news worth celebrating. An estimated 154 million lives have been saved by vaccination since the inception of the program. That averages to about six lives every minute of every day of every year saved by vaccination! Of these, the measles vaccine is estimated to have had the greatest impact, saving about 60% of those lives — three or four of the six lives saved every minute of every day of every year. Yes, measles kills, but we can protect our babies through vaccination — more than 92 million babies who became adults have demonstrated that.

See the study.