Abstract
Background: US studies suggested that use of PCV-7 may be associated with increased incidence of complicated pneumonia. From September 2009 PCV7 was included in Hong Kong's publicly funded immunization schedule.
Methods: We performed a retrospective study using data from the central computerized database of all public hospitals in Hong Kong for children 18 yrs or below to determine rates of hospitalization pre- and post-PCV7 vaccination by retrieving all cases with a discharge diagnosis of pneumonia, complicated pneumonia, invasive pneumococcal diseases, pneumococcal bacteremia from Jan 2005 to Dec 2013. Records from one tertiary university hospital were conducted to evaluate the types of invasive pneumococcal diseases.
Results: From 2005 to 2013, annual incidence rates of pneumococcal bacteremia decreased by 40 to 50%. However, the adjusted incidence rates of complicated pneumonia for children under 18 years and under 5 years have increased from 6.9 (2005 to 2008) to 13.6/100,000/yr (2010 to 2013) (P< 0.01), and 14.1 to 28.5 respectively (P<0.01). In the Prince of Wales Hospital (PWH), 51 children were admitted with complicated pneumonia over the 9 year period with 35 (69%) presenting in the post-PCV period. 17 were due to Strept pnenmoniae with 4 deaths in the post-PCV7 period (due to serotype 3 and 19A).
Conclusion:We documented a significant increase of complicated pneumonia shortly after PCV7 vaccination was started in Hong Kong. Severe cases were caused by serotypes not covered by PCV7 or 10. PCV-13 booster may reduce severe infections due to serotypes 3 and 19A.
- © 2014 ERS