Last data update: Sep 16, 2024. (Total: 47680 publications since 2009)
Records 1-3 (of 3 Records) |
Query Trace: Ojwando J [original query] |
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Immunogenicity of the pentavalent rotavirus vaccine in African infants
Armah GE , Breiman RF , Tapia MD , Dallas MJ , Neuzil KM , Binka FN , Sow SO , Ojwando J , Ciarlet M , Steele AD . Vaccine 2012 30 Suppl 1 A86-93 We recently completed a double-blind, placebo-controlled, multicenter Phase III clinical trial of the pentavalent rotavirus vaccine (PRV) in three African countries, Ghana, Kenya, and Mali, from April 2007 to March 2009. The immunogenicity of PRV in African infants is described. In total, 5468 infants were randomized 1:1 to receive 3 doses of PRV or placebo at approximately 6, 10, and 14 weeks of age. Breastfeeding and concomitant administration of EPI vaccines, including OPV, were allowed, and HIV-infected infants were not excluded. Immunogenicity of PRV was assessed by measuring serum anti-rotavirus IgA responses, as well as serum neutralization antibody (SNA) to the human rotavirus serotypes G1, G2, G3, G4 and P1A[8] in approximately 150 infants per country. Sera were collected pre-dose 1 (pD1) and approximately 14 days post-dose 3 (PD3) for immunological analysis. For the sero-response rates (≥3-fold rise from pD1 to PD3), the number of subjects evaluable included those with both pD1 and PD3 data available. PRV was immunogenic in African children and significantly reduced severe RVGE in African children through the first two years of life. The pooled anti-rotavirus IgA sero-response rate was 78.3%, with consistent rates in each of the African sites: 73.8% (Kenya), 78.9% (Ghana), and 82.5% (Mali); but generally lower than that reported in Europe and USA. PD3 GMTs (28.2 dilution-units) were 5-10 times lower than those assessed in subjects in clinical trials in developed countries. SNA responses to human rotavirus serotypes G1-G4 and P1A[8] ranged from 6.3% (G3) to 26.5% (G4). PD3 SNA GMTs to G1 and P1A[8] were 4-fold and 3-fold lower respectively, when compared to the corresponding GMTs in subjects who received PRV in similar studies conducted in developed countries. PRV was immunogenic in African infants, and the anti-rotavirus IgA sero-response rates were similar across all three African sites although lower than those observed in Europe and USA. While immune correlates of protection have not been established for rotavirus, the findings are consistent with lower efficacy rates demonstrated during this trial. Further investigation is needed to understand the reason for the lower immunogenicity observed. |
Safety of the pentavalent rotavirus vaccine (PRV), RotaTeq(R), in Kenya, including among HIV-infected and HIV-exposed infants
Laserson KF , Nyakundi D , Feikin DR , Nyambane G , Cook E , Oyieko J , Ojwando J , Rivers SB , Ciarlet M , Neuzil KM , Breiman RF . Vaccine 2012 30 Suppl 1 A61-70 Two multicenter Phase III trials were conducted in five countries from March 2007 to March 2009 to evaluate the safety and efficacy of the pentavalent rotavirus vaccine (PRV), RotaTeq((R)), in Africa and Asia. In this report, we evaluate the safety of this vaccine, including among HIV-infected and HIV-exposed infants, in Kenya. 1308 Infants were randomized 1:1 to receive 3 doses of PRV/placebo at approximately 6, 10, and 14 weeks of age. HIV counseling and testing were offered to all participants. A positive PCR result indicated HIV infection; the presence of HIV antibody in PCR-negative children indicated HIV exposure without HIV infection. All serious adverse events (SAE) within 14 days of any dose, and vaccine-related SAEs, intussusception, and deaths occurring at any time during the study, were reported ("SAE surveillance"). In addition, 297 participants were followed for 42 days after any dose for any adverse event (AE), regardless of severity ("intensive safety surveillance"). The safety evaluation was stratified by HIV status. SAEs were reported in 20/649 vaccine recipients (3.1%) and 21/643 placebo recipients (3.3%) within 14 days following vaccination (p=0.9). The most common SAE in the vaccinated group was pneumonia (1.7%). No individual SAE was significantly more common among vaccine vs. placebo recipients. Seventy-two deaths were reported, 38 (5.9%) and 34 (5.3%) among vaccine and placebo recipients, respectively (p=0.66). No cases of intussusception were reported. During intensive safety surveillance, 137/147 (93.2%) vaccine recipients and 147/150 (98.0%) placebo recipients experienced one or more AEs (risk ratio=0.95; 95% CI: 0.91-1.0; p=0.05). 88.5% of the infants were tested for HIV infection; 21/581 (3.6%) children in the vaccine group and 17/577 (2.9%) in the placebo group were HIV-infected. Among the 37 HIV-infected infants with full safety follow-up, 5/21 (23.8%) vaccine recipients and 2/16 (12.5%) placebo recipients reported an SAE (p=0.67). In total, 12 deaths occurred among identified HIV-infected infants: 8 (38%) receiving vaccine vs. 4 (23.5%) receiving placebo (RR=1.6, 95% CI: 0.59-4.5). Among the 21 HIV-infected infants in the vaccine group, 2 of 8 deaths were gastroenteritis-related; among the 17 HIV-infected infants in the placebo group, 3 of 4 deaths were gastroenteritis-related. There were no significant differences in serious or non-serious AEs, including vaccine-related SAEs, between the 88 HIV-exposed vaccine recipients vs. the 89 HIV-exposed placebo recipients. PRV appears to be a safe intervention against rotavirus gastroenteritis among infants in Kenya. AEs, including serious AEs, were not associated with receipt of vaccine. Further, SAEs were not significantly more common among HIV-infected or HIV-exposed participants; however, the low number of HIV-infected infants did not provide sufficient power to fully assess safety in HIV- infected vaccine recipients. |
Efficacy of pentavalent rotavirus vaccine in a high HIV prevalence population in Kenya
Feikin DR , Laserson KF , Ojwando J , Nyambane G , Ssempijja V , Audi A , Nyakundi D , Oyieko J , Dallas MJ , Ciarlet M , Neuzil KM , Breiman RF . Vaccine 2012 30 Suppl 1 A52-60 BACKGROUND: Rotavirus gastroenteritis (RVGE) is a leading cause of death in African children. The efficacy of pentavalent rotavirus vaccine (PRV) against severe RVGE evaluated in Ghana, Kenya, and Mali in a randomized, double-blind, placebo-controlled trial, showed a combined regional efficacy of 39.3% (95% confidence interval [CI]: 19.1,54.7) in nearly 2 years of follow-up. This report concentrates on the Kenya findings. METHODS: Infants received 3 doses of PRV/placebo at approximately 6-, 10-, and 14-weeks of age. HIV testing was offered to all participants. Data on illness symptoms and signs were collected upon presentation to healthcare facilities, where stools were collected, and analyzed by rotavirus-specific enzyme-linked immunosorbent assay. The primary endpoint was severe RVGE (Vesikari score≥11), occurring ≥14 days following the third dose. At monthly home visits, symptoms of illnesses during the past 2 weeks were solicited and limited physical exams were performed; dehydration was defined by WHO's Integrated Management of Childhood Illness. FINDINGS: Vaccine efficacy (VE) against severe RVGE through nearly 2 years of follow-up among 1308 Kenyan children was 63.9% (95% CI: -5.9,89.8). Through the first year of life, VE against severe RVGE was 83.4% (95% CI: 25.5,98.2). From home visits, VE against all-cause gastroenteritis with severe dehydration was 34.4% (95% CI: 5.3,54.6) through the first year and 29.7% (95% CI: 2.5,49.3) through the entire follow-up period. The reduction in incidence of gastroenteritis with severe dehydration in the community during the first year of life (19.0 cases/100 person-years) was almost six times greater than the reduction in severe RVGE presenting to the clinic (3.3/100 person-years). Oral rehydration solution use was lower among PRV recipients (VE 23.1%, 95% CI: 8.8,35.1). An estimated 41% of gastroenteritis with severe dehydration in the first year reported at home was rotavirus-related. CONCLUSIONS: PRV significantly reduced severe RVGE in Kenya. The impact of PRV might be greatest in rural Africa in protecting the many children who develop severe gastroenteritis and cannot access health facilities. |
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