Effectiveness of Haemophilus influenzae type b Conjugate vaccine introduction into routine childhood immunization in Kenya.
CONTEXT: Haemophilus influenzae type b (Hib) conjugate vaccine is not perceived as a public health priority in Africa because data on Hib disease burden and vaccine effectiveness are scarce. Hib immunization was introduced in Kenyan infants in 2001. OBJECTIVE: To define invasive Hib disease incidenc...
| Päätekijät: | , , , , , , , , , , , |
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| Aineistotyyppi: | Journal article |
| Kieli: | English |
| Julkaistu: |
2006
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| _version_ | 1826289377196638208 |
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| author | Cowgill, K Ndiritu, M Nyiro, J Slack, M Chiphatsi, S Ismail, A Kamau, T Mwangi, I English, M Newton, C Feikin, DR Scott, J |
| author_facet | Cowgill, K Ndiritu, M Nyiro, J Slack, M Chiphatsi, S Ismail, A Kamau, T Mwangi, I English, M Newton, C Feikin, DR Scott, J |
| author_sort | Cowgill, K |
| collection | OXFORD |
| description | CONTEXT: Haemophilus influenzae type b (Hib) conjugate vaccine is not perceived as a public health priority in Africa because data on Hib disease burden and vaccine effectiveness are scarce. Hib immunization was introduced in Kenyan infants in 2001. OBJECTIVE: To define invasive Hib disease incidence and Hib vaccine program effectiveness in Kenya. DESIGN, SETTING, AND PATIENTS: Culture-based surveillance for invasive Hib disease at Kilifi District Hospital from 2000 through 2005 was linked to demographic surveillance of 38,000 children younger than 5 years in Kilifi District, Kenya. Human immunodeficiency virus (HIV) infection and Hib vaccination status were determined for children with Hib disease admitted 2002-2005. INTERVENTIONS: Introduction of conjugate Hib vaccine within the routine childhood immunization program at ages 6, 10, and 14 weeks beginning November 2001. MAIN OUTCOME MEASURES: Incidence of culture-proven Hib invasive disease before and after vaccine introduction and vaccine program effectiveness. RESULTS: Prior to vaccine introduction, the median age of children with Hib was 8 months; case fatality was 23%. Among children younger than 5 years, the annual incidence of invasive Hib disease 1 year before and 1 and 3 years after vaccine introduction was 66, 47, and 7.6 per 100,000, respectively. For children younger than 2 years, incidence was 119, 82, and 16 per 100,000, respectively. In 2004-2005, vaccine effectiveness was 88% (95% confidence interval, 73%-96%) among children younger than 5 years and 87% (95% confidence interval, 66%-96%) among children younger than 2 years. Of 53 children with Hib admitted during 2002-2005, 29 (55%) were age-ineligible to have received vaccine, 12 (23%) had not been vaccinated despite being eligible, and 12 (23%) had received 2 or more doses of vaccine (2 were HIV positive). CONCLUSIONS: In Kenya, introduction of Hib vaccine into the routine childhood immunization program reduced Hib disease incidence among children younger than 5 years to 12% of its baseline level. This impact was not observed until the third year after vaccine introduction. |
| first_indexed | 2024-03-07T02:27:57Z |
| format | Journal article |
| id | oxford-uuid:a645a5fb-7c21-41d6-9737-32551994686f |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T02:27:57Z |
| publishDate | 2006 |
| record_format | dspace |
| spelling | oxford-uuid:a645a5fb-7c21-41d6-9737-32551994686f2022-03-27T02:46:07ZEffectiveness of Haemophilus influenzae type b Conjugate vaccine introduction into routine childhood immunization in Kenya.Journal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:a645a5fb-7c21-41d6-9737-32551994686fEnglishSymplectic Elements at Oxford2006Cowgill, KNdiritu, MNyiro, JSlack, MChiphatsi, SIsmail, AKamau, TMwangi, IEnglish, MNewton, CFeikin, DRScott, JCONTEXT: Haemophilus influenzae type b (Hib) conjugate vaccine is not perceived as a public health priority in Africa because data on Hib disease burden and vaccine effectiveness are scarce. Hib immunization was introduced in Kenyan infants in 2001. OBJECTIVE: To define invasive Hib disease incidence and Hib vaccine program effectiveness in Kenya. DESIGN, SETTING, AND PATIENTS: Culture-based surveillance for invasive Hib disease at Kilifi District Hospital from 2000 through 2005 was linked to demographic surveillance of 38,000 children younger than 5 years in Kilifi District, Kenya. Human immunodeficiency virus (HIV) infection and Hib vaccination status were determined for children with Hib disease admitted 2002-2005. INTERVENTIONS: Introduction of conjugate Hib vaccine within the routine childhood immunization program at ages 6, 10, and 14 weeks beginning November 2001. MAIN OUTCOME MEASURES: Incidence of culture-proven Hib invasive disease before and after vaccine introduction and vaccine program effectiveness. RESULTS: Prior to vaccine introduction, the median age of children with Hib was 8 months; case fatality was 23%. Among children younger than 5 years, the annual incidence of invasive Hib disease 1 year before and 1 and 3 years after vaccine introduction was 66, 47, and 7.6 per 100,000, respectively. For children younger than 2 years, incidence was 119, 82, and 16 per 100,000, respectively. In 2004-2005, vaccine effectiveness was 88% (95% confidence interval, 73%-96%) among children younger than 5 years and 87% (95% confidence interval, 66%-96%) among children younger than 2 years. Of 53 children with Hib admitted during 2002-2005, 29 (55%) were age-ineligible to have received vaccine, 12 (23%) had not been vaccinated despite being eligible, and 12 (23%) had received 2 or more doses of vaccine (2 were HIV positive). CONCLUSIONS: In Kenya, introduction of Hib vaccine into the routine childhood immunization program reduced Hib disease incidence among children younger than 5 years to 12% of its baseline level. This impact was not observed until the third year after vaccine introduction. |
| spellingShingle | Cowgill, K Ndiritu, M Nyiro, J Slack, M Chiphatsi, S Ismail, A Kamau, T Mwangi, I English, M Newton, C Feikin, DR Scott, J Effectiveness of Haemophilus influenzae type b Conjugate vaccine introduction into routine childhood immunization in Kenya. |
| title | Effectiveness of Haemophilus influenzae type b Conjugate vaccine introduction into routine childhood immunization in Kenya. |
| title_full | Effectiveness of Haemophilus influenzae type b Conjugate vaccine introduction into routine childhood immunization in Kenya. |
| title_fullStr | Effectiveness of Haemophilus influenzae type b Conjugate vaccine introduction into routine childhood immunization in Kenya. |
| title_full_unstemmed | Effectiveness of Haemophilus influenzae type b Conjugate vaccine introduction into routine childhood immunization in Kenya. |
| title_short | Effectiveness of Haemophilus influenzae type b Conjugate vaccine introduction into routine childhood immunization in Kenya. |
| title_sort | effectiveness of haemophilus influenzae type b conjugate vaccine introduction into routine childhood immunization in kenya |
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