Researchers are attributing the decline in hospitalizations for pneumonia across all age groups — especially among older adults — to the introduction of the 7-valent pneumococcal conjugate vaccine in 2000.
"Our study demonstrates a huge benefit of immunizing infants with conjugate pneumococcal vaccines on both children and adults," Marie Griffin, MD, MPH, professor of preventive medicine and medicine at Vanderbilt University School of Medicine, told Infectious Disease News. "It also highlights the importance of monitoring the impact of national immunization policies and practices."
Griffin and colleagues used the Nationwide Inpatient Sample database to estimate annual rates of hospitalization for pneumonia from any cause. They looked at data from 1997 to 1999 and from 2007 to 2009 to determine how the childhood vaccine affected pneumonia-related hospitalizations since its introduction.
Although the protective effect of PCV7 (Prevnar 7, Pfizer) benefited both children and adults, the largest reductions of pneumonia-related hospitalizations were observed at extremes of age. For example, the annual rate of hospitalizations due to pneumonia among children aged younger than 2 years declined by 551.1 per 100,000 (95% CI, 445.1-657.1), meaning there were 47,000 fewer hospitalizations each year than expected had rates remained the same since before 2000. Those aged 85 years or older experienced an even greater decline in hospitalizations — 1,300.8 per 100,000 (95% CI, 984-1,617.6), or 73,000 fewer hospitalizations annually. Unvaccinated older adults accounted for more than half of the overall reduction in hospitalizations, the researchers said.
The overall age-adjusted annual reduction in hospitalizations due to pneumonia was 54.8 per 100,000 (95% CI, 41-68.5), or 168,000 fewer hospitalizations annually.
According to the researchers, the introduction of the 13-valent pneumococcal conjugate vaccine (Prevnar 13, Pfizer) in 2010 may offer additional protection for older adults.
"PCV13 may cause another large reduction in pneumonia hospitalizations; perhaps another 10%, we hope," Griffin said in a press release. "It is important for people to know that adults are benefiting from our childhood vaccine program. These are adults who won't be hospitalized, won't be getting antibiotics, or complications of hospitalizations, and won't be dying, since the risk of death is 5% to 12% when older adults are hospitalized with pneumonia. Vaccination with pneumococcal conjugate vaccines results in a tremendous public health benefit."
Marie Griffin, MD, MPH, can be reached at firstname.lastname@example.org.
Disclosure: Study researcher Carlos G. Grijalva, MD, MPH, reports financial relationships with GlaxoSmithKline and Pfizer. Griffin reports financial ties with Pfizer.