Immunogenicity and serotype-specific efficacy of a 9-valent pneumococcal conjugate vaccine (PCV-9) determined during an efficacy trial in The Gambia.

This study aimed to determine the immunogenicity of a 9-valent pneumococcal conjugate vaccine (PCV-9) in a subgroup of Gambian children enrolled in a large vaccine efficacy trial. To place the antibody results in context, in this paper we also report previously unpublished data on serotype-specific clinical vaccine efficacy from the main trial. In the sub-study, a single 2-4 ml venous blood specimen was collected from 212 Gambian children 4-6 weeks after the administration of a third dose of PCV-9 or placebo. IgG antibodies to pneumococcal serotype 1, 4, 5, 6B, 9V, 14, 18C, 19F and 23F polysaccharides were measured by ELISA. The proportions of infants with antibody concentrations above 0.2, 0.35 and 1.0 microg/ml, and the geometric mean concentrations (GMCs) of anti-pneumococcal polysaccharide antibodies were substantially higher for each serotype in children who received three doses of PCV-9 than those in the placebo group. Among PCV-9 recipients, GMCs ranged between 2.61 and 11.09 microg/ml with the highest being against serotype 14 and the lowest against 9V polysaccharide. The estimated overall protective antibody level for all nine serotypes, based on the vaccine efficacy against vaccine-type invasive pneumococcal disease (IPD) of 77% (95% CI: 51, 90) observed in the trial, was 2.3 microg/ml (95% CI: 1.0, 5.0). The PCV-9 studied was immunogenic in a Gambian population where it was also found to be efficacious.

Screening of human corneas for herpes simplex virus by tissue culture and polymerase chain reaction.

Superficial eye infections by herpes simplex virus (HSV) constitute a major cause of corneal disease, necessitating the need for corneal transplantation in many patients. Eighty-three corneas from 46 post-mortem donors received from the David Lucas Eye Bank in Manchester were analyzed by Vero cell culture and the polymerase chain reaction (PCR) technique to detect HSV. There was no evidence of a characteristic cytopathic effect in any of the cultures. A 350-bp PCR product corresponding to the HSV thymidine kinase (TK) was detected by southern blotting in only 2.4% (2/83) of samples. In contrast, approximately 70% of samples yielded a 758-bp PCR product. Although this low prevalence of HSV in corneas may be encouraging, it is high for the actual transplantation program if the viral DNAs maintain their abilities to replicate.