What is the number needed to treat (NNT) for pneumonia vaccination in individuals over 75 years old?

From the Guidelines

The number needed to treat (NNT) for pneumonia vaccination in individuals over 75 years old is approximately 20-50, meaning that 20-50 older adults would need to be vaccinated to prevent one case of pneumonia. For adults over 75, the pneumococcal vaccines recommended include the 20-valent pneumococcal conjugate vaccine (PCV20) or a combination of the 15-valent pneumococcal conjugate vaccine (PCV15) followed by the 23-valent pneumococcal polysaccharide vaccine (PPSV23) 1. These vaccines are particularly important for this age group as they are at higher risk for pneumococcal disease due to age-related immune system decline and higher prevalence of chronic conditions.

Key Points to Consider

• The NNT increases with age because vaccine effectiveness tends to decrease in older populations, though vaccination still provides significant protection against invasive pneumococcal disease, hospitalization, and mortality 1.
• The relatively low NNT demonstrates that pneumococcal vaccination is a cost-effective intervention for preventing pneumonia in the elderly population, with benefits clearly outweighing the minimal risks of vaccination side effects, which are typically limited to soreness at the injection site and mild fever 1.
• Recent guidelines recommend the use of PCV20 or a combination of PCV15 and PPSV23 for adults over 75, with the choice of vaccine and schedule depending on the individual's underlying medical conditions and previous vaccination history 1.

Vaccine Effectiveness and Recommendations

• The effectiveness of pneumococcal vaccines in preventing invasive pneumococcal disease and other outcomes has been demonstrated in several studies, with a recent study showing a 45% reduction in the incidence of all-cause pneumonia and a 64% reduction in pneumococcal pneumonia among nursing home residents 1.
• The Advisory Committee on Immunization Practices (ACIP) recommends pneumococcal vaccination for all adults aged 65 years and older, with specific recommendations for the use of PCV20, PCV15, and PPSV23 depending on the individual's underlying medical conditions and previous vaccination history 1.

From the Research

Pneumonia Vaccination in Individuals Over 75 Years Old

• The number needed to treat (NNT) for pneumonia vaccination in individuals over 75 years old is not directly stated in the provided studies.
• However, a study published in 2015 2 reported the efficacy of 13-valent polysaccharide conjugate vaccine (PCV13) in preventing first episodes of vaccine-type strains of pneumococcal community-acquired pneumonia in adults 65 years of age or older.
• The vaccine efficacy was 45.6% (95.2% confidence interval [CI], 21.8 to 62.5) for community-acquired pneumonia, 45.0% (95.2% CI, 14.2 to 65.3) for nonbacteremic and noninvasive community-acquired pneumonia, and 75.0% (95% CI, 41.4 to 90.8) for invasive pneumococcal disease.
• Another study published in 2022 3 evaluated the field effectiveness of PCV13, PPSV23, and sequential vaccination against pneumococcal pneumonia in older adults, but the results were statistically insignificant for the elderly aged ≥65 years.
• The study found that sequential PCV13/PPSV23 vaccination showed the highest adjusted vaccine effectiveness of 80.3% (95% CI, 15.9%-95.4%) in the younger subgroup (aged 65-74 years).
• There are no direct calculations of NNT provided in the studies, but the vaccine efficacy and effectiveness reported can be used to estimate the potential benefit of pneumonia vaccination in individuals over 75 years old 2, 3, 4, 5, 6.