Public health impact of Infanrix hexa (DTPa-HBV-IPV/Hib) reimbursement: A study programme in France. Part 1: Evolution of hepatitis B vaccine coverage rates in infants aged less than 27 months, in the general population - the PopCorn study.

Background: Reimbursement of the hexavalent vaccine (Infanrix hexa) comprising the DTPa-IPV-Hib components and the hepatitis B valence in a single vaccine was decided in March 2008 in France. The impact of its reimbursement on the hepatitis B vaccine coverage rate was assessed in a study conducted in the general population prior to and after implementation of the reimbursement policy.

Methods: The PopCorn study (NCT01782794) was a national, cross-sectional and repeated study, with four assessment periods over 3 years, from 2009 to 2012, to assess the hepatitis B vaccine coverage in 12- to 15- and 24- to 27-month-old children, vaccinated between 2007 and 2011 and selected by the quota sampling method. Face-to-face interviews were conducted at their homes and vaccination status was collected using their child's health record. Parents were also interviewed on their perceptions and acceptance of hepatitis B vaccination. Three indicators were calculated to assess hepatitis B vaccination coverage: proportions of infants with at least one dose before 6 months of age, with at least two doses before 6 months of age and with a complete schedule at 24 months of age.

Results: A total of 4903 children were enrolled in the study. An overall significant increase (P-value [P<0.05]) of the three indicators of interest over the four periods of time was observed for both age groups. The proportion of children receiving hepatitis B vaccination before 6 months increased from 21% at baseline (before vaccine reimbursement) to almost 75% at the last assessment period in 2012. More than 60% of 24- to 27-month-old children received a complete schedule in 2012 compared to 33% at baseline. No significant increases in the proportions of parents "favourable" and "moderately in favour" of hepatitis B vaccination were observed across the four evaluation periods (respectively, 17-22% and 48-50%, P=0.09).

Conclusion: The rapid increase of hepatitis B vaccination coverage suggests a significant change in hepatitis B vaccination practice related to the hexavalent vaccine's reimbursement. This change was observed in a context of stability regarding parents' perceptions and acceptance of hepatitis B vaccination and of coverage rates for other infant vaccinations.