(13.0 cases of pneumonia per 1,000 days a ventilator was used) (CDC, 2000e).
The nosocomial transfer of antimicrobial-resistant organisms to patients remains a significant concern. Looking specifically at ICU patients with nosocomial infections in 2000, NNIS found that more than 55 percent of Staphylococcus aureus isolates were resistant to methicillin, oxacillin, or nafcillin. Methicillin-resistant S. aureus increased 29 percent in 2000 as compared with the mean of the previous 5 years (1995–1999). Resistance of Pseudomonas aeruginosa to quinolones increased 53 percent during the same period in the same population; vancomycin-resistant enterococci increased 31 percent (National Nosocomial Infections Surveillance System, 2001).
Vaccine-preventable diseases still cause millions of deaths each year, mainly in developing countries. Indeed, nearly 3 million people worldwide die annually from major vaccine-preventable diseases.
Childhood immunizations have contributed to a significant reduction in vaccine-preventable diseases, including measles, mumps, rubella, pertussis, and other potentially devastating illnesses. Yet there remains a sizable segment of the population, both in the United States and internationally, that does not receive childhood vaccinations. Several reasons may account for low vaccine rates, including misperceptions about the actual risk for a given disease, concerns about the safety of vaccines due to widely publicized but unsubstantiated claims of adverse effects, and the absence of a health infrastructure for vaccine purchase and delivery. In Africa, for example, only 55 percent of the population in the region had vaccination coverage for polio and measles in 2000 (WHO, 2001g). That same year, the Americas vaccinated 90 percent of the population against both diseases.
Even in the United States, vaccine-preventable diseases cause staggering numbers of deaths and illnesses. For example, pneumonia and influenza deaths together constitute the sixth leading cause of death in the United States. Influenza causes an average of 110,000 hospitalizations and 20,000 deaths annually; pneumococcal disease causes 10,000 to 14,000 deaths annually (DHHS, 2000b). The annual estimate of influenza vaccination for adults aged 65 and older (those at increased risk for severe disease or death from influenza) is roughly 65 percent. Moreover, the percentage of older adults reported as ever having received a pneumococcal vaccination is even lower. The Healthy People 2010 target is to increase to 90 percent the proportion of noninstitutionalized adults aged 65 and older who are vaccinated annually against influenza and who have ever been vaccinated against pneumococcal disease (DHHS, 2000b).