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Effectiveness of pneumococcal conjugate vaccine (PCV) against presumed bacterial pneumonia (PBP) in South African HIV-uninfected children: A case-control study
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| Speaker: |
Shabir Madhi
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| Author: |
S.A. Madhi1, M. Groome1, H. Zar2, C. Kapongo3, C. Mulligan2, D. Moore1, E. Zell4, C. Whitney4, J. Verani4
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| Affiliation: |
1Department of Science/ National Research Foundation: Vaccine Preventable Diseases & Respiratory and Meningeal Pathogens Research Unit, University of the Witwatersrand, Faculty of Health Science, Johannesburg, 2Department of Child and Adolescent Health, University of Cape Town, Cape Town, 3Department of Paediatrics, Ngwelezane Hospital, Richards Bay, South Africa, 4Division of Bacterial Diseases, Center for Diseases Control and Prevention, Atlanta, MO,
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Background: PCV-7 was introduced in South Africa in April 2009 with doses at 6, 14 and 40 weeks and no- catch-up.
Aim: A case-control study to evaluate PCV effectiveness against PBP in South African HIV-uninfected children.
Methods: Study sites included two urban (CHBH and Red Cross) and one rural (Ngwelezane) hospital. PBP cases were children age-eligible for =1 dose of PCV hospitalized for clinical pneumonia, with either alveolar consolidation on CXR per WHO criteria (CXR-AC) or other CXR infiltrate with serum CRP=40mg/l. At least one hospital control matched for age, HIV status and hospital was enrolled for each PBP case. For PBP cases at CHBH, we also enrolled =3 community controls matched by age. Effectiveness was calculated as 1 minus matched odds ratio for vaccination. Up-to-date vaccination was receipt of =2 doses if 16-40 weeks or =3 doses if >40 weeks of age.
Results: To date, 696 cases (551 [79.2%] with CXR-AC) were matched to 952 hospital controls, with mean ages of 38.8 and 39.1 weeks, respectively. 527 cases (85.6% with CXR-AC) were also matched to 1484 community controls. The effectiveness of up-to-date PCV was 27.3% (95%CI: 0-49.2) when using hospital controls and 58.9% (95%CI: 37.5-72.9) using community controls. The effectiveness of two doses in children aged 16-40 weeks was 40.7% (95%CI: 2.0-64.1) and 56.8% (95%CI: 23.1-75.7) using hospital and community controls, respectively.
Conclusions: PCV prevents PBP in HIV-uninfected children. Varied results using different control groups suggest potential biases in control enrollment that need further exploration.
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