Researchers at the University of Arizona Mel and Enid Zuckerman College of Public Health investigating trends in infectious disease mortality in the United States showed that the flu or pneumonia caused the most deaths from 1980 through 2014, but overall the number of deaths from infections has remained stable. The study, published in the Nov. 22 issue of the Journal of the American Medical Association (JAMA), illustrates our continued vulnerability to infectious diseases.
“This study takes a look at the big picture, to see where we have improved and what areas we need to turn our attention to. … [We] see that overall infectious disease mortalities haven’t really changed over the last 30 years but the cause of those deaths has changed,” said Victoria Hansen, author of the study which was part of her thesis while a graduate student in epidemiology at the UA Zuckerman College of Public Health.
As was shown before in a previous study, from 1900 through 1996, mortality from infectious diseases mostly declined in the United States, except for a 1918 spike due to the Spanish flu pandemic and an HIV related increase. To examine more recent changes, the authors used data from the National Office of Vital Statistics reports from 1900 through 1967 and from the U.S. Centers for Disease Control and Prevention WONDER database from 1968 through 2014. Since 1980 the team found, major changes in infectious diseases such as the introduction of human immunodeficiency virus HIV/AIDS and mosquito-borne West Nile virus into the United States, advances in HIV/AIDS treatment, changes in vaccine perceptions, and increased concern over antibiotic-resistant pathogens.
Overall infectious disease mortality decreased from 1900 through 1950 (except for the 1918 spike) and then leveled off. From 1980 through 2014, infectious diseases composed 5.4 percent of overall mortality. Per 100,000 population, infectious disease mortality increased from 42 in 1980 to 64 in 1995, paralleling trends in HIV/AIDS mortality. A decline in overall and HIV/AIDS mortality in 1995 was associated with the introduction of antiretroviral therapy. Most infectious disease deaths (38 percent) from 1980 through 2014 were due to influenza or pneumonia.
Vaccine-preventable disease death rates decreased since 1980. Mortality due to hepatitis B alone showed an increase coincident with the HIV/AIDS epidemic. Mortality due to pathogens with drug-resistant strains remained stable since 1980. Mortality from Clostridium difficile, a hospital-acquired infection with drug resistance, increased from almost none in 1989 until reaching a plateau since 2007.
“As far as new challenges, it’s a matter of staying vigilant and being ready for new diseases to pop up. Pathogens will continue to mutate and new diseases will continue to emerge and we need to be ready,” said Ms. Hansen.
Ms. Hansen currently works as an epidemiologist and data manager for the Arizona Department of Health Services in Phoenix. She graduated with an MS in epidemiology in 2015.
Infectious Disease Mortality Trends in the United States, 1980-2014
Victoria Hansen, MS; Eyal Oren, PhD; Leslie K. Dennis, PhD; Heidi E. Brown, PhD.; University of Arizona Mel and Enid Zuckerman College of Public Health.