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Introduction: Singapore had its first case of pandemic influenza A (H1N1) 2009 on 26 May 2009. As of 3 August 2009, 440 children with confirmed H1N1were admitted to KK Women's and Children's Hospital (KKH)., Materials and Methods: This is a retrospective case control study of children admitted from 26 May 2009 to 19 July 2009 with H1N1infection. Cases and controls were first differentiated by whether they were complicated or non-complicated in nature, and subsequently analysed with regards to possible independent risk factors., Results: We analysed 143 admitted children; 48 cases and 95 controls (1: 2 ratio). Significant comorbidity was found in 20.3% (n = 29) of patients with the majority having asthma (n = 18, 12.6 %) followed by obesity (n = 7, 4.9%). Binary logistic regression analysis showed risk factors for complicated disease were comorbidity (adjusted OR 6.0, 95% CI, 2.5 to 14.6, P < 0.0001) and age <2 years (adjusted OR 9.8, 95% CI, 2.4 to 40, P = 0.001). Age less than 5 years was not found to be a risk factor., Conclusion: In the early stages of an evolving influenza epidemic when oseltamivir stocks are low, oseltamivir treatment for influenza can be streamlined and offered to those at highest risk who are under 2 years old or have significant comorbidity to prevent complicated disease.

Background: Influenza can produce significant complications in immunocompromised persons., Methods: We studied the effects of the pandemic (H1N1) 2009 (pH1N1) infection on solid organ transplant recipients in our hospital, with emphasis on clinical information, duration of viral culture positivity, polymerase chain reaction positivity, effects of oseltamivir therapy, and graft status at 6 months of follow-up., Results: Twenty-two cases of pH1N1 infection involving 18 renal, two lung, one heart, and one liver transplant recipients were seen from July 14 to September 8, 2009. Their median age was 50.5 years (range 20-70 years); 64% were women, and median time posttransplant was 40 months (range 6-204 months). Common symptoms were fever (86%), cough (77%), sore throat (55%), phlegm (32%), and myalgia (27%). The median duration of symptoms (n=21) and duration of polymerase chain reaction positivity (n=15) were 7 (range 4-13 days) and 8 days (range 4-16 days), respectively. Mean (± SD) duration of symptom resolution (7.4 ± 3.0 vs. 7.8 ± 3.0 days, P=0.76) and viral culture positivity (5.3 ± 2.8 vs. 4.3 ± 3.2 days, P=0.65) did not differ between those who received a 5-day (n=9) or 10-day (n=12) course of oseltamivir. Five patients (22.7%) developed pneumonia with three needing intensive care. Mortality rate was 4.5% (1/22). At 6 months, three graft rejections involving two renal and one lung developed., Conclusions: Our findings indicate that the pH1N1 infection in solid organ transplant recipients is associated with some degree of morbidity and may affect the function of the transplanted organ. In this nonrandomized comparison, patients treated with 5 days of oseltamivir did not fare worse compared with those who received 10 days.

Relatively few international comparisons of the incidence of influenza related to climate parameters have been performed, particularly in the Eastern hemisphere. In this study, the incidence of influenza and climate data such as temperature, relative humidity, and rainfall, from cities at different latitudes with contrasting climates: Singapore, Hong Kong (China), Ulaanbaatar (Mongolia), Vancouver (Canada), and three Australian cities (Brisbane, Melbourne and Sydney) were examined to determine whether there was any overall relationship between the incidence of influenza and climate. Applying time-series analyses to the more comprehensive datasets, it was found that relative humidity was associated with the incidence of influenza A in Singapore, Hong Kong, Brisbane, and Vancouver. In the case of influenza B, the mean temperature was the key climate variable associated with the incidence of influenza in Hong Kong, Brisbane, Melbourne, and Vancouver. Rainfall was not significantly correlated with the incidence of influenza A or B in any of these cities., (© 2010 Wiley-Liss, Inc.)

Introduction: Influenza A H1N1 (2009) pandemic has affected countries worldwide including Singapore. Data on obstetric outcomes of women with H1N1 (2009) in pregnancy are lacking., Materials and Methods: This was an observational study analysing the obstetric outcomes of pregnant women with influenza A H1N1 (2009) infection who had delivered at a viable gestation (24 weeks or more) in our centre., Results: Between 23 June 2009 and 30 September 2009, 235 pregnant women were diagnosed with influenza A H1N1 (2009) at our centre, with 42 having delivered and comprising the study cohort. Median age was 27.5 years (range, 16 to 42). Multiparous women comprised 59.5% (25/42) whilst 40.5% (17/42) were primiparous. In terms of ethnicity, 61.9% were Malays, 26.2% Chinese, 4.8% Indians and 7.1% Others. All women received oseltamivir. All had shown recovery from the acute influenza infection. There were no respiratory complications. Twenty-nine women (69.0%) delivered at term. Twenty-fi ve women (59.5%) had spontaneous labour whilst 15 (35.7%) had labour induction. Two women (4.8%) did not labour. Thirty-six women (85.7%) had vaginal delivery, of whom 3 were instrumental deliveries. Apgar scores of greater than 8 at 1 min and 5 min were documented in babies of 95.2% (40/42) women, respectively. Thirty-two women (76.2%) delivered babies with birthweights greater than 2500 g. Compared with historical data from 2008, the H1N1 cohort had comparable mean birthweight and average gestational age at delivery of 38 weeks., Conclusion: Our study suggested that obstetric outcomes were not adversely affected by influenza A H1N1 (2009) infection.

Introduction: Influenza vaccine has been shown to be highly effective in temperate regions with well-defined seasonal influenza. Healthcare workers (HCWs) are advised to receive regular influenza vaccination to protect themselves and their patients. However, there are limited data on the efficacy of influenza vaccine in HCWs in the tropics., Materials and Methods: In this observational, investigator blinded cohort study, bi-monthly questionnaires recording influenza-like illness (ILI) episodes and medical leave were administered to 541 HCWs at the Singapore National University Hospital and KK Women's and Children's Hospital from 2004 to 2005. ILI was defined according to a standard symptom score., Results: Baseline characteristics were comparable in both the vaccinated and non-vaccinated groups. Overall, the relative risk of self-reported ILI in vaccinated HCWs was 1.13 [95% confidence interval (CI), 0.98-1.13; P=0.107]; medical leave taken was lower in the vaccinated group [mean 0.26+/-0.6 days per visit, compared with 0.30+/-0.5 days in the non-vaccinated group (P=0.40)]. Because of the reported Northern Hemisphere 2003/04 vaccine mismatch, we stratified the cohort and determined that the group which received a matched vaccine had a relative risk of ILI of 0.49 (95% CI, 0.37-0.66; P<0.001), achieving a vaccine efficacy of 51%. Mean medical leave decreased significantly in HCWs who received the matched vaccine, compared with those who did not receive vaccination (0.13+/-0.3 vs 0.30+/-0.5; P<0.001) and with HCWs vaccinated with mismatched strains (0.13+/-0.3 vs 0.39+/-0.9; P=0.01)., Conclusions: A well-matched influenza vaccine is effective in preventing ILI and reducing sickness absence in healthcare workers in tropical settings. Efforts need to be made to increase influenza vaccination rates and to improve the currently available vaccines.