Obstetric outcomes of influenza A H1N1 (2009) infection in pregnancy--experience of a Singapore tertiary hospital

<p><b>INTRODUCTION</b>Influenza A H1N1 (2009) pandemic has affected countries worldwide including Singapore. Data on obstetric outcomes of women with H1N1 (2009) in pregnancy are lacking.</p><p><b>MATERIALS AND METHODS</b>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.</p><p><b>RESULTS</b>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.</p><p><b>CONCLUSION</b>Our study suggested that obstetric outcomes were not adversely affected by influenza A H1N1 (2009) infection.</p>

The efficacy of influenza vaccination in healthcare workers in a tropical setting: a prospective investigator blinded observational study

<p><b>INTRODUCTION</b>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.</p><p><b>MATERIALS AND METHODS</b>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.</p><p><b>RESULTS</b>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).</p><p><b>CONCLUSIONS</b>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.</p>