2727. Numbers Needed to Vaccinate for Prevention of Adult Pneumonia with Pneumococcal Conjugate Vaccine: Which Values Should Determine Policy?

BACKGROUND: At the meeting of the Advisory Committee on Immunization Practices (ACIP) on February 28, 2019, the US Centers for Disease Control and Prevention (CDC) and the Pneumococcal Work Group (PWG) presented data to inform the public health question of whether the 13-valent pneumococcal conjugate vaccine (PCV13) should continue to be recommended for routine immunization of all adults age 65 years and older in the United States. METHODS: We reviewed all three available studies reporting adult PCV13 vaccine effectiveness against all-cause pneumonia, calculated numbers needed to vaccinate (NNV), and compared these results to NNV data presented to the ACIP based on etiologically and radiologically confirmed vaccine-type (VT) disease. Studies included a randomized controlled trial of inpatient pneumonia among Dutch persons age 65+ years, a US CDC-led observational study among the US Medicare population of inpatient pneumonia, and an observational study of inpatient and outpatient pneumonia in Germany. RESULTS: Based on a background incidence of etiologically and radiologically confirmed VT community-acquired pneumonia of 17–76 per 100,000 per year and PCV13 VE of 43%, the CDC presented to ACIP an annual NNV estimate for preventing one pneumonia case of 3,000 to 14,000. For the three studies we reviewed, VEs were 6% to 12% against all-cause pneumonia and background all-cause pneumonia incidences were 891 to 1776 per 100,000 per year. Assuming a 5-year PCV13 duration of protection, for these three studies NNVs to prevent a case of pneumonia were 95 to 277, or 11- to 147-fold lower than what was presented at ACIP. CONCLUSION: To avoid inaccurate conclusions for potentially efficient interventions, calculations of NNVs, rate reductions, and economic benefits should include sensitive outcomes, such as all-cause pneumonia, in addition to more specific but lower sensitivity outcomes such as VT, radiologically confirmed pneumonia. DISCLOSURES: All authors: No reported disclosures.