Effectiveness of Haemophilus influenzae type b conjugate vaccine on radiologically-confirmed pneumonia in young children in Pakistan.

Objective: The effectiveness of Haemophilus influenzae type b (Hib) vaccine in preventing severe pneumonia in Asian children has been questioned, and many large Asian countries yet to introduce Hib conjugate vaccine in immunization programs. The primary objective of this study was to assess Hib conjugate vaccine effectiveness (VE) on radiologically-confirmed pneumonia in children born after introduction of Hib conjugate vaccine in Pakistan.

Study Design: A matched case-control study enrolled cases of radiologically-confirmed pneumonia in several hospitals serving low-income populations during 2009-2011.