TUESDAY, Nov. 13 (HealthDay News) -- The incidence of vaccine-preventable deaths has reached an all-time low in the United States, a new federal report shows.
The study, by researchers at the U.S. Centers for Disease Control and Prevention, also found that childhood vaccinations have reduced the death rates from seven previously common childhood illnesses, such as diphtheria, mumps and measles, by 100 percent.
"The number of cases of most vaccine-preventable diseases is at an all-time low; hospitalizations and deaths have also shown striking decreases," wrote the authors of the study, which is published in the Nov. 14 issue of the Journal of the American Medical Association.
The study compared the number of cases and deaths for 13 vaccine-preventable deaths: diphtheria; pertussis (whooping cough); tetanus; polio; measles; mumps; rubella (German measles); invasive Haemophilus influenza type b (Hib); acute hepatitis B; hepatitis A; varicella (chickenpox); Streptococcus pneumoniae (pneumococcal); and smallpox. The researchers compared the most recent data on illnesses (from 2006) and deaths (from 2004) to pre-vaccination rates.
Overall, for immunizations developed prior to 1980, there was a 92 percent reduction in vaccine-preventable illnesses and a 99 percent or greater decline in deaths due to vaccine-preventable diseases. For vaccines introduced after 1980, including the hepatitis vaccines, Hib and chickenpox, there was an 80 percent or greater decline in illness and deaths. Cases of invasive pneumococcal disease were down 34 percent, and death rates were down 25 percent.
At the peak incidence of diphtheria in the 1930s, more than 30,000 people in the United States developed the disease each year, and 3,000 died. Today, there have been no reported cases or deaths in the country. Whooping cough, which also peaked in the 1930s, used to affect more than 200,000 people every year and killed as many as 7,500 people. Today, about 15,000 people are infected with pertussis annually, and less than 30 people die each year. (An additional pertussis booster vaccination has been recommended for adults and will likely reduce these rates even further, the researchers said.)
"These achievements are largely due to reaching and maintaining high vaccine coverage levels from infancy throughout childhood by successful implementation of the infant and childhood immunization program," the authors said.
"These results are very exciting," said Dr. Louis Saravolatz, an infectious disease expert and chief of internal medicine at St. John Hospital and Medical Center in Detroit. "If you look at a particular age cohort, you see a phenomenal reduction of about 33,000 deaths prevented. That means 33,000 people from that group are still alive today, because they were vaccinated."
Any gains made can be lost, however, if parents stop immunizing their children, or if teens and adults don't get necessary booster immunizations.
"These vaccines work, and they improve the health of our children and our population, and we should be very grateful for that," said Dr. Marian Michaels, an infectious disease specialist at Children's Hospital of Pittsburgh. "But, we should not become complacent. These diseases aren't eradicated everywhere, and the world is so globally small now that these infections could come back if we don't maintain high immunization rates."
Saravolatz said that while this study is "great news," there is definitely still room for improvement in reducing disease in other parts of the world, and in the United States to strengthen adult vaccination rates.
"We need to do a better job in adult medicine, for pneumococcal vaccine and the influenza vaccine. Pediatricians are much more in tune with immunization schedules, and we have aggressive school programs, and we provide childhood vaccines for free. With adult vaccinations, a disparity still exists," Saravolatz said.
The CDC has more on how vaccines work.
SOURCES: Marian Michaels, M.D., infectious disease specialist, Children's Hospital of Pittsburgh; Louis Saravolatz, M.D., chief, internal medicine, and infectious disease expert, St. John Hospital and Medical Center, Detroit; Nov. 14, 2007, Journal of the American Medical Association