The day before Thanksgiving, researchers published an article in the New England Journal of Medicine that took a comprehensive look at contagious diseases in the U.S. for over a century.  Researchers used data from weekly surveillance reports that included information on notifiable diseases.  Based on this extraction and a subsequent analysis, researchers found a quantitative trend of disease reduction and concluded that much of this was due to the effectiveness of vaccination programs.

As part of the study, SF Gate reports that researchers have examined and digitized weekly reports covering 87 million cases of 56 contagious diseases.  At first, researchers only digitized select reports, but after a handful of times, they determined that having all of the records digitized would be most useful in the long run.

Researchers argued that the project could play a critical role in preventing or mitigating epidemics.  Researchers can analyze the patterns of epidemics in the past, what caused them to be large one year and small the next year, which will help scientists to predict the course of future epidemics and the potential impact of interventions.

Prior to conducting and publishing their research, the team conducted an analysis on the effect of vaccines on prevalence of certain diseases.  Researchers concluded that the incidence of diseases such as measles and rubella fell dramatically and almost immediately after vaccines became available.  For those diseases, there were some very abrupt declines.  The authors indicated that they had not expected those very sudden changes.  While these declines could be attributed to the impact of vaccinations, researchers also noted there was a resurgence of certain diseases, such as pertussis, also known as whooping cough.  This was true despite the availability of vaccines, but they hope the data will help determine the cause.

This study focused on notifiable diseases.  MedlinePlus describes notifiable diseases, also known as reportable diseases, as diseases considered to be of great public health importance. Local, state, and national agencies (for example, county and state health departments or the U.S. Centers for Disease Control and Prevention) require that these diseases be reported when they are diagnosed by doctors or laboratories.  Reporting allows for the collection of statistics that show how often the disease occurs. This helps researchers identify disease trends and track disease outbreaks. This information can help control future outbreaks.

Reportable diseases include a variety of contagious diseases including anthrax, botulism, cholera, diphtheria, hepatitis, plague, rabies, tuberculosis, and a variety of sexually transmitted infections.