The effect of routine vaccination in the Czech Republic on the incidence of invasive diseases caused by Haemophilus influenzae b

Abstract

Objectives: The paper is an analysis of the results of a five-year surveillance programme in the Czech Republic (1999-2003); it evaluates the efficacy of routine Hib vaccination that started in July 2001.

Material and methods: Morbidity due to Hib was explored in a surveillance programme, which since 2002 also included the investigation of Hib vaccine failure. Hib identification was carried out with standard methods, serotypes were verified using PCR, biotyping was carried out in all strains and in selected strains also multilocus sequential typing.

Results: In the years 1999-2003 invasive Hib disease presented mostly as meningitis, followed by epiglottitis. Mortality due to an invasive Hib disease was in the years 1999-2003 2.3 %. Among the Hib strains isolated in invasive disorders predominated the biotype I and the sequence type ST-6.

Conclusions: Following the introduction of routine Hib vaccination in the Czech Republic there was an overall drop in morbidity due to Hib invasive disorders. This was most obvious in a decrease in the morbidity of Hib meningitis and in the vaccinated age group. Two years after the introduction of routine Hib vaccination morbidity dropped by 81 % in children aged 0 to 1 year. In higher age groups there was no change in the number of invasive Hib disease. Neither was there an increase in "non-b" haemophilus invasive disorders. Failure of Hib vaccination is a rare occurence.