Impact of non-routine vaccination on the incidence of invasive Haemophilus influenzae type b (Hib) disease: experience in the autonomous region of Valencia, Spain.
OBJECTIVE
This study assessed the impact of non-routine vaccination against invasive Haemophilus influenzae (Hib)disease before the introduction of universal childhood Hib vaccination.


METHODS
Data were obtained from a prospective surveillance program for invasive bacterial diseases in children <15 years of age that was begun in the Autonomous Region of Valencia on 1 December 1995.


RESULTS
An incidence of 15.5 cases of invasive Hib disease per 100,000 children <5 years of age was reported in the first year of the surveillance program (from 1 December 1995 to 30 November 1996), when Hib vaccination coverage was estimated to be 32.5%. An increase in vaccination coverage to 44% in the second year (1 December 1996 to 30 November 1997) was associated with a reduction in disease incidence to 3.3 cases per 100,000. After the initiation of universal vaccination in December 1998, only two cases were reported. The effectiveness of non-routine vaccination was 71% in 1997.


CONCLUSIONS
These results show that before the introduction of routine childhood Hib vaccination, widespread use of the vaccine can dramatically reduce the occurrence of invasive Hib disease.
Díez-Domingo
J
J
Research Unit Trinitat, Vaccine Institute of Valencia, Spain.
Pereiró
I
I
Morant
A
A
Gimeno
C
C
San-Martín
M
M
González
A
A
D002675:Child, Preschool; D006192:Haemophilus Infections / Q000453:epidemiology / Q000517:prevention & control*; D018073:Haemophilus Vaccines / Q000008:administration & dosage*; D019741:Haemophilus influenzae type b / Q000302:isolation & purification; D006801:Humans; D017589:Immunization Programs; D007223:Infant; D007231:Infant, Newborn; D011159:Population Surveillance; D015397:Program Evaluation; D011446:Prospective Studies; D013030:Spain / Q000453:epidemiology
D018073:Haemophilus Vaccines