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Effectiveness of seven-valent pneumococcal conjugate vaccine (PCV7) against invasive pneumococcal disease in South Africa: a matched case-control study
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| Speaker: |
Cheryl Cohen
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| Author: |
C. Cohen1, C. von Mollendorf1, N. Naidoo1, V. Nokeri1, V. Quan1, M. Fortuin de Smit1, S. Meiring1, B. Kgokong1, G. Nelson2, D. Moore3, M. Moshe4, S.A. Madhi1, B. Eley5, U. Hallbauer6, G. Ruebenson7, E. Zell2, L. Conklin2, K. Klugman8, C. Whitney2, A. von Gottberg1, South A
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| Affiliation: |
1National Institute for Communicable Diseases: a division of National Health Laboratory Services, Johannesburg, South Africa, 2Centres for Disease Control and Prevention, Atlanta, GA, USA, 3Chris Hani Baragwanath Hospital, Johannesburg, 4Dr George Mukhari Hospital, Pretoria, 5Red Cross Children’s Hospital, Cape Town, 6Universitas and Pelonomi Hospitals, Bloemfontein, 7Rahima Moosa Hospital, Johannesburg, South Africa, <
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Background: South Africa introduced PCV7 in April 2009 using a three-dose schedule (6 and 14 weeks and 9 months) with no catch-up. We present preliminary analysis of the effectiveness of =2 PCV7 doses against vaccine-serotype invasive pneumococcal disease (IPD) and all IPD in HIV-infected and -uninfected children.
Methods: Invasive disease (pneumococcus isolated from a sterile site) was identified in children aged = 16 weeks through national laboratory-based surveillance. Isolates were serotyped by Quellung or PCR. Four hospitalized controls, matched for age, HIV-status and hospital were selected for each case. We calculated effectiveness as 1 minus matched odds ratio for vaccination.
Results: We enrolled 133 HIV-uninfected cases and 535 controls and 83 HIV-infected cases and 254 controls from March 2010 through September 2011. Coverage with =2 doses was 65% (346/535 [71/346, 21% received =3 doses]) in HIV-uninfected and 67% (170/254 [52/170, 31% =3 doses]) in HIV-infected controls. Effectiveness of =2 doses against vaccine serotypes was 68% (95% CI:4,89) in HIV-uninfected and -18% (95%CI: -303,65) in HIV-infected children. Effectiveness against all IPD was 46% (95% CI: -2,71) in HIV-uninfected and 26% (95% CI: -62,66) in HIV-infected children. In the subgroup aged 16-40 weeks effectiveness against vaccine serotypes was 79% (95% CI: 5,95) in HIV-uninfected and 51% (-440,96) in HIV-infected children and remained unchanged for all IPD.
Conclusions: Preliminary results indicate that PCV7 is protecting HIV-uninfected children in South Africa. A schedule including three primary doses, efficacious among HIV-infected children in an earlier South African trial, may be needed for HIV-infected children.
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