2 research outputs found
Epidemiology and Molecular Characterization of Influenza Viruses Isolated From Children Admitted At the Kenyatta National Hospital in April-July 2008
No full textBackground: 20% of deaths in children are caused by respiratory infections. Acute respiratory infections (ARIs), have both bacterial and viral aetiologies. Influenza viruses cause highly contagious respiratory diseases. In Kenya, three studies focusing on influenza-like-illness and severe acute respiratory illness are ongoing. Despite these surveillance programmes, little is known regarding the epidemiology and molecular characteristics of influenza viruses found in children at the KenyattaNational Hospital (KNH). Objective: To determine the epidemiology and molecular characteristics of influenza viruses from children at the Kenyatta National Hospital during the April-July 2008 period. Methodology: Throat swabs were collected from 388 consenting patients. Swabs were inoculated onto monolayers of cultured MDCK cellsto isolate influenza viruses. The virus isolates were identified by HA/HAI assays. Viral RNA was extracted from isolates followed by RT-PCR amplification of the haemagglutinin gene.Nucleotide sequences were determined by the Sanger dideoxy termination method on an ABI 3500xL genetic analyzer. The nucleotide sequences were aligned to similar sequences from GenBank, and phylogeny inferred using Bayesian methods. Results: Twenty viruses consisting of 19 (95%) influenza B viruses and 1 (5%) seasonal influenza A/H1N1 were detected from the 388 patient samples. HAI titres for both A and B viruses ranged between 320-1280 with both vaccine strains showing a titre of 320. Viruses were detected mostly in 1year olds (11; 55%), patients with LRTI (14; 70%) and in the month of June (9; 45%). The nucleotide sequences displayed had 97-98%similarities to other 2008 influenza sequences. Phylogenetic analyses of seasonal influenza A/H1N1 clustered together with 2008 regional sequences while influenza B also clustered with 2008 sequences. Influenza A sequence showed substitutions at one antigenic site (198-Sb), while 3 antigenic sites (150loop, 160loop and 190 – Helix) on influenza B also had substitutions when compared to the 2008 vaccine strains. Conclusion: In 2008, influenza viruses were common in 1year oldsat KNH. Infection rates were highest in the month of June. Viruses isolated in the study period were genetically similar to those isolated elsewhere. Amino acid changes in the Kenyan isolates did not adversely affect the immunogenicity of the 2008 vaccine
Efficacy and safety of the RTS,S/AS01 malaria vaccine during 18 months after vaccination : a phase 3 randomized, controlled trial in children and young infants at 11 African sites
Get PDFA malaria vaccine could be an important addition to current control strategies. We report the safety and vaccine efficacy (VE) of the RTS,S/AS01 vaccine during 18 mo following vaccination at 11 African sites with varying malaria transmission.; 6,537 infants aged 6-12 wk and 8,923 children aged 5-17 mo were randomized to receive three doses of RTS,S/AS01 or comparator vaccine. VE against clinical malaria in children during the 18 mo after vaccine dose 3 (per protocol) was 46% (95% CI 42% to 50%) (range 40% to 77%; VE, p>0.01 across all sites). VE during the 20 mo after vaccine dose 1 (intention to treat [ITT]) was 45% (95% CI 41% to 49%). VE against severe malaria, malaria hospitalization, and all-cause hospitalization was 34% (95% CI 15% to 48%), 41% (95% CI 30% to 50%), and 19% (95% CI 11% to 27%), respectively (ITT). VE against clinical malaria in infants was 27% (95% CI 20% to 32%, per protocol; 27% [95% CI 21% to 33%], ITT), with no significant protection against severe malaria, malaria hospitalization, or all-cause hospitalization. Post-vaccination anti-circumsporozoite antibody geometric mean titer varied from 348 to 787 EU/ml across sites in children and from 117 to 335 EU/ml in infants (per protocol). VE waned over time in both age categories (Schoenfeld residuals p>0.001). The number of clinical and severe malaria cases averted per 1,000 children vaccinated ranged across sites from 37 to 2,365 and from -1 to 49, respectively; corresponding ranges among infants were -10 to 1,402 and -13 to 37, respectively (ITT). Meningitis was reported as a serious adverse event in 16/5,949 and 1/2,974 children and in 9/4,358 and 3/2,179 infants in the RTS,S/AS01 and control groups, respectively.; RTS,S/AS01 prevented many cases of clinical and severe malaria over the 18 mo after vaccine dose 3, with the highest impact in areas with the greatest malaria incidence. VE was higher in children than in infants, but even at modest levels of VE, the number of malaria cases averted was substantial. RTS,S/AS01 could be an important addition to current malaria control in Africa
