Childhood vaccinations are ultimately worth whatever risks they may present, say scientists, because they prevent contagious diseases which once took many, many lives. In fact, a new study just published in The New England Journal of Medicine says that 100 million cases of contagious disease have been prevented in the United States since 1924.
The study was conducted by a team of scientists from the University of Pittsburgh’s graduate school of public health by examining public health reports dating back to the 1800’s. Fifty-six different diseases were included in the study, but the journal article kept its focus on just seven important ones: diphtheria, hepatitis A, measles, mumps, pertussis, polio and whooping cough.
The research team examined reports both before and after vaccines became widely available. They then estimated the number of prevented cases by calculating how much the numbers of reported cases fell after vaccines became available. From this, they were able to provide an educated guess as to how many cases of the disease might have occurred if vaccines were not discovered. These figures were adjusted for America’s growing population as well.
The team of scientists considered the idea of also looking at death rates from these diseases, but concluded that it would not work, mainly because of the inconsistency and lack of reliability in death certificate data. Good data only became available in the 1960’s
However, the lead author of the study, Dr. Donald S. Burke, was willing to make a guess at prevented deaths, stating that a reasonable estimate based upon known mortality rates for these diseases would be about three to four million deaths prevented.
The authors note that cases of some of these diseases – such as whooping cough – have begun to rise in recent years, due to parents choosing to avoid vaccinations. As an example, there were 38,000 reported cases of whooping cough in the U.S. just last year, representing the worst epidemic since 1959.
According to the authors of the study, events like this illustrate quite well just why parents need to consider the benefits versus the risks of vaccinations. While vaccinations are occasionally associated with problems – such as the recent death of a 19-year-old after receiving a flu vaccination – the benefits are generally considered to be greater than the risks by the scientific community. The numbers of prevented deaths to due to contagious diseases greatly outnumbers any rare cases of death or disability due to vaccine side effects.
Compiling the data was quite a task; Burke and his colleague William van Panhuis were able to digitize weekly reports for over 87 million cases of 56 different contagious diseases reported between the years of 1888 to 2011. The data from the project, called Project Tycho after the astronomer Tycho Brahe, is freely available to all through the University of Pittsburgh website, which can be accessed in the sources below.
By Nancy Schimelpfening