Timing of hepatitis B vaccination and impact of non-simultaneous vaccination with DTP vaccine following introduction of a hepatitis B birth dose in the Philippines

Timely administration of hepatitis B vaccine beginning at birth prevents up to 95 per cent of perinatally acquired hepatitis B virus infections in infants of infected mothers. The Philippines changed its national HepB schedule in 2007 to include a dose at birth. We evaluated vaccination schedule change by reviewing infant records at selected health facilities to measure completeness and timeliness of HepB administration and frequency of recommended, simultaneous vaccination with diphtheria-tetanus-pertussis (DTP) vaccine. Of 1431 sampled infants, 1106 (77 per cent) completed the HepB series and 10 per cent followed the national schedule. The proportion with timely vaccination declined with successive doses: HepB1 (71 per cent), HepB2 (47 per cent), and HepB3 (26 per cent). Twenty-six per cent received HepB2 simultaneously with DTP1 and 34 per cent received HepB3 simultaneously with DTP3. If HepB and DTP vaccination were given simultaneously, 10 per cent more infants could have received all HepB doses. Program implementers should monitor vaccination timeliness and increase simultaneous administration to improve vaccination coverage and decrease disease incidence.