What is the number needed to treat (NNT) for pneumonia vaccination in preventing invasive pneumococcal disease?

From the Guidelines

The number needed to treat (NNT) for pneumonia vaccination in preventing invasive pneumococcal disease is approximately 1,000 for higher-risk populations, as supported by recent studies 1. This means that about 1,000 higher-risk individuals would need vaccination to prevent one case of invasive pneumococcal disease. The pneumococcal vaccines available include the 23-valent pneumococcal polysaccharide vaccine (PPSV23, Pneumovax), which has been shown to be effective in preventing invasive pneumococcal disease in adults, including the elderly, with a protective efficacy of 40-75% 1. Key factors influencing the NNT include the population's baseline risk of invasive disease, with higher-risk groups such as older adults, those with chronic conditions, and immunocompromised patients having a more favorable NNT due to their increased baseline risk. Recent studies have demonstrated the effectiveness of pneumococcal vaccination in preventing invasive pneumococcal disease, with one 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 NNT is an important statistical measure that helps clinicians and patients understand the magnitude of benefit from pneumococcal vaccination in different populations, and it is essential to consider the NNT when making decisions about pneumococcal vaccination, particularly in higher-risk populations 1. Some of the key points to consider when evaluating the NNT for pneumococcal vaccination include:

• The population's baseline risk of invasive disease
• The effectiveness of the vaccine in preventing invasive pneumococcal disease
• The potential benefits and risks of vaccination
• The cost-effectiveness of vaccination in different populations. Overall, the NNT for pneumonia vaccination in preventing invasive pneumococcal disease is an important consideration in clinical practice, and recent studies support the use of pneumococcal vaccination in higher-risk populations to prevent invasive pneumococcal disease 1.

From the FDA Drug Label

The secondary endpoint: First episode of VT-IPD 35 7 28 75 (41.1,90.9)

To calculate the Number Needed to Treat (NNT) for pneumonia vaccination in preventing invasive pneumococcal disease, we can use the vaccine efficacy (VE) data from the trial.

• Vaccine Efficacy (VE): 75% (41.1,90.9)
• Events in treatment group: 7
• Events in control group: 35
• NNT calculation: NNT = 1 / (control group event rate - treatment group event rate)
• Control group event rate: 35 / 42256
• Treatment group event rate: 7 / 42240
• NNT: NNT = 1 / ((35/42256) - (7/42240)) ≈ 1 / (0.000827 - 0.000165) ≈ 1 / 0.000662 ≈ 1510

The NNT for pneumonia vaccination in preventing invasive pneumococcal disease is approximately 1510 2.

From the Research

Pneumonia Vaccination and NNT

• The number needed to treat (NNT) for pneumonia vaccination in preventing invasive pneumococcal disease is not directly stated in the provided studies.
• However, a study published in 2015 3 reported the efficacy of 13-valent polysaccharide conjugate vaccine (PCV13) in preventing first episodes of vaccine-type strains of pneumococcal community-acquired pneumonia and invasive pneumococcal disease in adults 65 years of age or older.
• The study found that PCV13 had a vaccine efficacy of 45.6% in preventing community-acquired pneumonia, 45.0% in preventing nonbacteremic and noninvasive community-acquired pneumonia, and 75.0% in preventing invasive pneumococcal disease.
• To calculate the NNT, the absolute risk reduction (ARR) is needed, which can be calculated using the vaccine efficacy and the control group event rate.
• Assuming a control group event rate of 0.1% (90 cases per 84,496 participants) for community-acquired pneumonia, the ARR would be 0.0456 (vaccine efficacy) x 0.001 (control group event rate) = 0.000456, and the NNT would be 1 / 0.000456 = 2195.
• For invasive pneumococcal disease, assuming a control group event rate of 0.033% (28 cases per 84,496 participants), the ARR would be 0.75 (vaccine efficacy) x 0.00033 (control group event rate) = 0.000248, and the NNT would be 1 / 0.000248 = 4032.
• However, these calculations are based on the provided study and may not be generalizable to other populations or settings.

Limitations and Considerations

• The provided studies do not directly address the NNT for pneumonia vaccination in preventing invasive pneumococcal disease.
• The calculations above are based on a single study and may not be representative of the entire population.
• The NNT may vary depending on the specific vaccine, population, and setting.
• Other factors, such as cost-effectiveness and potential side effects, should also be considered when evaluating the use of pneumonia vaccination.