Although every visit to a health professional provides an opportunity for immunization, the proportion of the target population that is adequately vaccinated is only about one-half for influenza vaccine and one-fourth for pneumococcal vaccine. Coverage for hepatitis B vaccine varies from 1 percent to 60 percent (average 10 percent) depending on the population. Adequate antibody titers against tetanus and diphtheria are present in approximately 40 percent of adults.
Vaccines are available to prevent a number of illnesses that contribute to morbidity and mortality in adults in the United States.
- Influenza is responsible for 20,000 to 40,000 deaths annually, and up to 50,000 deaths and an estimated 200,000 excess hospitalizations at a cost of $750 million to $1 billion during epidemic years.
- Mortality from all pneumococcal disease is estimated at 40,000 deaths annually, with morbidity estimated at 500,000 cases of pneumonia, 50,000 cases of sepsis, and 3,000 cases of meningitis.
- Hepatitis B infections occur in 200,000 to 300,000 people per year and result in 10,000 to 15,000 hospitalizations and 250 deaths due to fulminant hepatitis.
- Approximately 1 million people are carriers of the hepatitis B virus; 25 percent have chronic active hepatitis, 4,000 die annually from HBV-related cirrhosis, and 800 die annually from HBV-related liver cancer.