Haemophilus influenzae Type b Vaccine Failure in Portugal: A Nationwide Multicenter Pediatric Survey.

Background: Despite the high effectiveness of the Haemophilus influenzae type b (Hib) vaccine in preventing invasive disease (ID) in children, Hib vaccine failures (VFs) cases may still occur. This study aimed to characterize the Hib-VF cases in Portugal in a 12-year period and trying to identify the possible associated risk factors.

Methods: Prospective descriptive nationwide surveillance study.