Advertisement

 

 

Pneumococcal responses are similar in Papua New Guinean children aged 3-5 years vaccinated in infancy with pneumococcal polysaccharide vaccine with or without prior pneumococcal conjugate vaccine, or without pneumococcal vaccination.

Pneumococcal responses are similar in Papua New Guinean children aged 3-5 years vaccinated in infancy with pneumococcal polysaccharide vaccine with or without prior pneumococcal conjugate vaccine, or without pneumococcal vaccination.
Author Information (click to view)

van den Biggelaar AHJ, Richmond PC, Fuery A, Anderson D, Opa C, Saleu G, Lai M, Francis JP, Alpers MP, Pomat WS, Lehmann D,


van den Biggelaar AHJ, Richmond PC, Fuery A, Anderson D, Opa C, Saleu G, Lai M, Francis JP, Alpers MP, Pomat WS, Lehmann D, (click to view)

van den Biggelaar AHJ, Richmond PC, Fuery A, Anderson D, Opa C, Saleu G, Lai M, Francis JP, Alpers MP, Pomat WS, Lehmann D,

Advertisement
Share on FacebookTweet about this on TwitterShare on LinkedIn

PloS one 2017 10 1312(10) e0185877 doi 10.1371/journal.pone.0185877
Abstract
TRIAL DESIGN
In an earlier trial, Papua New Guinean (PNG) children at high risk of pneumococcal disease were randomized to receive 0 or 3 doses of 7-valent pneumococcal conjugate vaccine (PCV7), followed by a single dose of 23-valent pneumococcal polysaccharide vaccine (PPV23) at 9 months of age. We here studied in a non-randomized follow-up trial the persistence of pneumococcal immunity in these children at 3-5 years of age (n = 132), and in 121 community controls of a similar age with no prior pneumococcal vaccination.

METHODS
Circulating IgG antibody titers to all PCV7 and PPV23-only serotypes 2, 5 and 7F were measured before and after challenge with 1/5th of a normal PPV23 dose. Serotype-specific memory B-cells were enumerated at 10 months and 3-5 years of age for a subgroup of study children.

RESULTS
Serotype-specific IgG antibody titers before and after challenge were similar for children who received PCV7/PPV23, PPV23 only, or no pneumococcal vaccines. Before challenge, at least 89% and 59% of children in all groups had serotype-specific titers ≥ 0.35μg/ml and ≥ 1.0 μg/ml, respectively. Post-challenge antibody titers were higher or similar to pre-challenge titers for most children independent of pneumococcal vaccination history. The rise in antibody titers was significantly lower when pre-challenge titers were higher. Overall the relative number of serotype-specific memory B-cells remained the same or increased between 10 months and 3-5 years of age, and there were no differences in serotype-specific memory B-cell numbers at 3-5 years of age between the three groups.

CONCLUSIONS
Immunity induced by PCV7 and/or PPV23 immunization in infancy does not exceed that of naturally acquired immunity in 3-5-year-old children living in a highly endemic area. Also, there was no evidence that PPV23 immunization in the first year of life following PCV7 priming induces longer-term hypo-responsiveness.

TRIAL REGISTRATION
Clinicaltrials.gov NCT01414504 and NCT00219401.

Submit a Comment

Your email address will not be published. Required fields are marked *

17 − seven =

[ HIDE/SHOW ]