Immunogenicity and Impact on Nasopharyngeal Carriage of a Nonavalent Pneumococcal Conjugate Vaccine

Abstract

The safety, immunogenicity, and impact on carriage of a nonvalent pneumococcal vaccine given at ages 6, 10, and 14 weeks were examined in a double-blind, randomized, placebo-controlled trial in 500 infants in Soweto, South Africa. No serious local or systemic side effects were recorded. Significant antibody responses to all pneumococcal serotypes were observed 4 weeks after the third dose. Haemophilus influenzae type b polyribosylribitol phosphate (geometric mean titer, 11.62 microg/mL) and diphtheria (1.39 IU/mL) antibodies were significantly higher in children receiving pneumococcal conjugate, compared with placebo recipients (4.58 microgram/mL and 0.98 IU/mL, respectively). Nasopharyngeal carriage of vaccine serotypes decreased in vaccinees at age 9 months (18% vs. 36%), whereas carriage of nonvaccine serotypes increased (36% vs. 25%). Carriage of penicillin-resistant pneumococci (21% vs. 41%) and cotrimoxazole-resistant pneumococci (23% vs. 35%) were significantly reduced 9 months after vaccination, compared with controls.

Antibiotic-Resistant Streptococcus pneumoniae in the Heptavalent Pneumococcal Conjugate Vaccine Era: Predictors of Carriage in a Multicommunity Sample

“…Previous studies have documented reduced carriage of vaccine-included strains after immunization. 16,22,23 Our data confirm that PCV7 immunization substantially reduced carriage with PCV7 serotypes, but immunization was not associated with lower rates of S pneumoniae carriage overall. This is additional indirect evidence for serotype replacement among organisms colonizing the nasopharynx after immunization.…”

“…20,21 However, children remain at risk from serotypes not included in PCV7. Colonization with pneumococcal vaccine serotypes 16,22,23 has been shown to decrease shortly after immunization, but longer-term changes in colonization patterns in communities remain unclear. The possibility exists that serotypes with which children have traditionally been colonized may be replaced by nonvaccine serotypes as predominant colonizers in a community, possibly leading to increased risk of infection by these organisms.…”

Genomic interrogation of ancestral Mycobacterium tuberculosis from south India

“…In the largest BCG trial conducted in the same region earlier, BCG did not afford any protection. It is known that genetic variation of the strains is a method of vaccine escape and has been demonstrated in several bacterial species (Van Loo et al, 2002, Mbelle et al, 1999. Further investigation in this line would be helpful to ascertain the role of these highly prevalent strains on the host immunity.…”

Meeting the challenge: prevention of pneumococcal disease with conjugate vaccines

“…In the controlled trial done in Soweto, South Africa by Mbelle and associates, results showed that vaccination with a 9-valent pneumococcal vaccine significantly reduced nasopharyngeal carriage of serotypes 19F and 6B. 104 Serotypes 6A and 6B differ only in the linkage of a single sugar in the carbohydrate molecule, and it is of some concern that the vaccine did not reduce carriage of serotype 6A. 114 Fifteen percent of the residual nasopharyngeal carriage of antibiotic-resistant strains in the study was due to the continued carriage of serotype 6A.…”

“…The impact of a conjugate vaccine on pneumococcal carriage was studied by Mbelle and colleagues. 104 The study evaluated the safety, immunogenicity, and impact on carriage of a pneumococcal 9-valent (serotypes 1, 4, 5, 6B, 9V, 14, 18C, 19F, and 23F) conjugate vaccine (PNCRM9). The 9-valent vaccine was administered at ages 6, 10, and 14 weeks in a double-blind, randomized, placebo-controlled trial in 500 infants in Soweto, South Africa.…”