Vaccine effectiveness during a varicella outbreak among schoolchildren: Utah, 2002-2003.

OBJECTIVES: In the context of a chickenpox outbreak involving 2 Utah elementary schools, we conducted an investigation to assess vaccine effectiveness, describe illness severity, and examine risk factors for breakthrough varicella (ie, varicella in those who have been vaccinated). METHODS: All parents were asked to complete a questionnaire about their child's medical history. Parents of children with recent varicella were interviewed, and vaccination records were verified. Lesions were submitted for polymerase chain reaction testing. RESULTS: Questionnaires were returned for 558 (93%) of 597 students in school A and 924 (97%) of 952 students in school B. A total of 83 schoolchildren (57 unvaccinated and 26 vaccinated) had varicella during the October 2002 through February 2003 outbreak period. An additional 17 cases occurred among household contacts, including infants and adults. Polymerase chain reaction analysis recovered wild-type varicella. Vaccine effectiveness was 87%. With 1 notable exception, vaccinated children tended to have milder illness. Risk factors for breakthrough varicella included eczema, vaccination > or =5 years before the outbreak, and vaccination at < or =18 months of age. Restricting analysis to children vaccinated > or =5 years before the outbreak, those vaccinated at < or =18 months of age were more likely to develop breakthrough varicella (relative risk: 9.3; 95% confidence interval: 1.3-68.9). CONCLUSIONS: The vaccine, administered by >100 health care providers to 571 children during a 7-year time period, was effective. Risk factors for breakthrough varicella suggest some degree of biological interaction between age at vaccination and time since vaccination.

Biosensor analysis of the interaction between drug compounds and liposomes of different properties; a two-dimensional characterization tool for estimation of membrane absorption.

The interactions between 78 drug compounds and immobilised liposomes were investigated using an assay based on surface plasmon resonance technology. The drugs were screened at a single concentration and allowed to interact simultaneously with two different types of liposomes. When the drug-liposome responses are plotted against one another they generally fall into three distinct bands: low response-low percent fraction absorbed in humans (Fa), medium response-medium Fa, and high response-high Fa. For drugs with medium to high Fa values, basic compounds could be resolved from acidic and neutral compounds to a large extent. This technique has the potential to be utilized as a screening tool for binning novel compounds into low, medium, or high Fa based on a simple experimental measurement. The assay was applied to 11 kinase inhibitors, 9 thrombin inhibitors, and 11 carbonic anhydrase inhibitors highlighting a subset that may have incomplete intestinal absorption (low to medium Fa). Assay conditions were optimized making the assay suitable for routine analysis and for compound characterization early in drug discovery where solubility may be an issue.