Decreased point prevalence of Haemophilus influenzae type b (Hib) oropharyngeal colonization by mass immunization of Brazilian children less than 5 years old with hib polyribosylribitol phosphate polysaccharide-tetanus toxoid conjugate vaccine in combination with diphtheria-tetanus toxoids-pertussis vaccine.
A protective herd effect has been described after susceptible populations of children are vaccinated with conjugate Haemophilus influenzae type b (Hib). Hib carriage was studied in children aged 6-24 months attending day care centers in two cities in southern Brazil (Curitiba and Porto Alegre). In Curitiba, routine immunization with Hib polyribosylribitol phosphate polysaccharide-tetanus toxoid conjugate vaccine (PRP-T) in combination with diphtheria-tetanus toxoids-pertussis vaccine (PRP-T/DTP) has been offered since September 1996; DTP vaccine alone is routinely given in Porto Alegre. Children in Porto Alegre (n=643) were 8 times less likely to have received adequate Hib vaccination and 4 times more likely to be Hib carriers than children in Curitiba (n=647; i.e., point prevalence of oropharyngeal colonization, 4.8% vs. 1.2%). Point prevalence of carriage with non-type b or other nontypeable Hi was similar in children of both cities. There was a vaccination effect on carriage rates in children who received a primary 3-dose series, independent of the booster dose, suggesting that a booster may be unnecessary to induce population protection.
Forleo-Neto
E
E
Dept. Medico, Pasteur Mérieux Connaught do Brasil, Rua do Rocio 351-10 degrees andar, 04552-905, São Paulo/SP, Brazil. forleo@grogbrasil.com.br
de Oliveira
C F
CF
Maluf
E M
EM
Bataglin
C
C
Araujo
J M
JM
Kunz
L F
LF
Pustai
A K
AK
Vieira
V S
VS
Zanella
R C
RC
Brandileone
M C
MC
Mimica
L M
LM
Mimica
I M
IM
D001938:Brazil; D002353:Carrier State / Q000382:microbiology; D002656:Child Day Care Centers; D002675:Child, Preschool; D015721:Diphtheria-Tetanus-Pertussis Vaccine; D005006:Ethnicity; D005260:Female; D018073:Haemophilus Vaccines; D006193:Haemophilus influenzae / Q000302:isolation & purification* / Q000502:physiology; D006798:Housing; D006801:Humans; D007223:Infant; D008297:Male; D009960:Oropharynx / Q000382:microbiology*; D013745:Tetanus Toxoid; D018074:Vaccines, Conjugate
D015721:Diphtheria-Tetanus-Pertussis Vaccine; D018073:Haemophilus Vaccines; C055753:Haemophilus influenza type b polysaccharide vaccine-tetanus toxin conjugate; D013745:Tetanus Toxoid; D018074:Vaccines, Conjugate