Meteorological factors and El Nino Southern Oscillation are associated with paediatric varicella infections in Hong Kong, 2004-2010.

Varicella accounts for substantial morbidities and remains a public health issue worldwide, especially in children. Little is known about the effect of meteorological variables on varicella infection risk for children. This study described the epidemiology of paediatric varicella notifications in Hong Kong from 2004 to 2010, and explored the association between paediatric varicella notifications in children aged <18 years and various meteorological factors using a time-stratified case-crossover model, with adjustment of potential confounding factors. The analysis found that daily mean temperature, atmospheric pressure and Southern Oscillation Index (SOI) were positively associated with paediatric varicella notifications. We found that an interquartile range (IQR) increase in temperature (8·38°C) at lag 1 day, a 9·50 hPa increase in atmospheric pressure for the current day, and a 21·91 unit increase in SOI for the current day may lead to an increase in daily cases of 5·19% [95% confidence interval (CI) 1·90-8·58], 5·77% (95% CI 3·01-8·61), and 4·32% (95% CI 2·98-5·68), respectively. An IQR increase in daily relative humidity (by 11·96%) was associated with a decrease in daily paediatric varicella (-2·79%, 95% CI -3·84 to -1·73). These findings suggest that meteorological factors might be important predictors of paediatric varicella infection in Hong Kong.

Establishment of platelet donor registry improves the treatment of platelet transfusion refractoriness in Guangzhou region of China.

Platelet transfusion refractoriness (PTR) is the major complication of long-term platelet supportive care. To improve the effectiveness of platelet transfusion therapy in PTR patients, we aimed to establish a platelet donor registry in our region (Guangzhou, China) by typing the human leukocyte antigen (HLA) and human platelet antigen (HPA). Blood donors (n = 864) from our population were genotyped for HLA-A, HLA-B and HPA systems by polymerase chain reaction amplification with sequence-specific primer(PCR-SSP) techniques. Using this cohort, we compared the results of platelet transfusions (matched vs. random) in 23 patients with PTR. Matched platelets were selected either by HLA antigen matching or by HLA antibody matching, as predicted by antibody specificity prediction (ASP) analysis. Significantly higher platelet recovery (PPR) values were obtained with HLA-matched platelets in comparison with random platelets. No significant difference in PPR was observed between HLA matching and ASP methods. In two patients, platelet-specific alloantibodies (alloabs) (anti-HPA-3b and anti-HPA-5b) were detected besides HLA class I alloabs. Transfusion with HLA- and HPA-compatible platelets in both the patients resulted in significantly higher PPR when compared with HLA-compatible platelet transfusion alone. In this study, we demonstrated that the establishment of an HLA- and HPA-typed platelet aphaeresis donor registry is useful to improve the treatment outcome of PTR patients and to maintain a long-term platelet transfusion strategy.