Recently, controversy has emerged regarding the role of the 23vPPV in infants due to potential immunological hypo-responsiveness (i.e. a poorer immune response to repeat vaccination). Although previous experience of 23vPPV in children in PNG has demonstrated protective efficacy against acute lower respiratory tract infection, the investigators feel it is a matter of urgency to determine if 23vPPV administration provides elevated antibody concentrations at 3 to 5 years of age, and to ensure the immunological safety of the 23vPPV in infants. Following consent and eligibility assessment, a baseline blood sample and nose swab will be taken, a 0.1ml dose of 23vPPV will be administered and a follow up blood sample and nose swab will be collected 28 days later. The investigators will also collect data on incidence of ALRI in all study participants by medical record review.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
NONE
Enrollment
280
0.5mL dose of Prevenar at 0-1-2 months, 0.5mL Pneumovax at 9 months and 0.1mL Pneumovax at 3-5 yrs
0.5mL Prevenar at 1-2-3 months,0.5mL Pneumovax (PPV) at 9 months, 0.1mL Pneumovax at 3-5 yrs
no Prevenar, 0.5mL Pneumovax at 9 months, 0.1mL Pneumovax at 3-5 yrs
control, 0.1mL Pneumovax at 3-5yrs
PNG Institute of Medical Research
Goroka, Eastern Highlands Province, Papua New Guinea
Measure serotype-specific antibody persistence in children aged 3-5 years after vaccination with 23vPPV at 9 months of age and compared to unvaccinated controls.
Children who were previously vaccinated with Pneumovax (23vPPV) at 9 months will be followed up at age 3-5 years of age. They will be given a challenge dose of Pneumovax (0.1mL) and followed up 1 months later. Age matched controls identified from each villages will also be recruited and given a challenge dose of Pneumovax. Serotype-specific antibodies will be measure pre- and post-challenge dose to determine anitbody levels.
Time frame: 2yrs
Measure the number of circulating serotype-specific memory B-cells pre- & post- booster immunisation
Time frame: 2yrs
Measure nasopharyngeal pneumococcal serotype-specific carriage rates pre- and post- 23vPPV challenge dose
Time frame: 2yrs
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