Influenza A (H1N1) 2009 Pandemic Calm Down the Prevalence of Acute Hepatitis A in the Latter Half of 2009: Korean Population Study / 대한소화기학회지

BACKGROUND/AIMS: There was a spiking incidence of acute hepatitis A (AHA) in 2009 summer, but it went down drastically after an outbreak of influenza A (H1N1). We assessed the relationship between 2009 H1N1 pandemic and AHA prevalence from August to December 2009. METHODS: We compared AHA cases nationwide and in our hospital for the period from the latter half of 2008 to the end of 2010. H1N1 cases in our hospital from August 2009 to December 2009 were included in the study and the correlation between 2009 H1N1 pandemic and AHA prevalence was assessed. RESULTS: The national surveillance system reported 2,233, 7,895, 15,231 and 7,660 AHA cases from 2007 to 2010, respectively. A similar trend was noted in our hospital in the same periods. Although the national total incidence was increased in 2009, it showed steep decreasing trend line in the final 21 weeks of 2009 (weeks 32-52), as compared with 2008 and 2010. The mean weekly incidence percentage (AHA cases in a week/total in a year) in weeks 32-52 of 2009 was 1.17+/-0.55%, significantly lower than that in 2008 and 2010 (1.61+/-0.43% and 1.56+/-0.51%; p<0.001). Furthermore, we found a significant negative correlation between 2009 H1N1 pandemic and AHA in our hospital for weeks 32-52 of 2009 (r=-0.597; p<0.001). CONCLUSIONS: The widespread occurrence of 2009 H1N1 pandemic highlighted the benefits of health care and good hygiene, such as effective hand washing and wearing of masks, which may have also interrupted hepatitis A virus transmission.

The Sensitivity according to the Time Gap between Fever Onset and the Performance of Rapid Antigen Test for 2009 H1N1 Influenza / 소아알레르기및호흡기학회지

PURPOSE: Rapid antigen test (RAT) is used to screen influenza rapidly. The clinical sensitivity of RAT was poor for 2009 H1N1 influenza. The aim of this study was to identify the correlation of time gap (TG) between fever onset and the sensitivity of RAT for 2009 H1N1 influenza. METHODS: Data were collected retrospectively during the pandemic H1N1 2009 influenza season between October 2009 and February 2010. The RAT was done by using SD Bioline influenza antigen (Standard Diagnostics Inc.) in nasopharyngeal swab. The 2009 H1N1 influenza was confirmed by real-time reverse transcriptase polymerase chain reaction (rRT-PCR). Specimens were categorized according to the TG between fever onset and performance of RAT. They were classified into 120 hours (TG6). RESULTS: The overall sensitivity of RAT was 69.9%. The TG dependent sensitivity of RAT at TG1, TG2, TG3, TG4, TG5, and TG6 was 64.3%, 73.3%, 61.1%, 88.9%, 83.3%, and 61.1% respectively. The sensitivity of RAT was the highest when the TG was 72 to 96 hours. But this result was not statistically significant. CONCLUSION: Correlation of TG between fever onset and the sensitivity of RAT for 2009 H1N1 influenza was not statistically significant. But our study suggested that 72 to 96 hours after fever onset is the most sensitive time of RAT. Timely optimal performance of the RAT could have a significant impact on improving results. Further evaluation for better sensitivity would be needed.

Risk Factors For Prolonged Shedding of 2009 H1N1 Influenza Virus.

This retrospective study was conducted to estimate the shedding of 2009 H1N1 virus and the risk analysis by review of medical charts, laboratory and radiological findings of all inpatients with confirmed pandemic influenza A (H1N1) at a provincial pediatric hospital. A total of 41 cases attending the inpatient department between 15 November, 2009 to 14 December, 2009 were included. Prolonged and discontinuous shedding of 2009 H1N1 virus (median, 10days; range, 2 to 24 days) were detected by real-time RT-PCR. The interval from onset of symptom to the start of oseltamivir therapy was an independent risk factor for prolonged virus shedding.

2009 H1N1 influenza virus infection and necrotizing pneumonia treated with extracorporeal membrane oxygenation / 소아과

A 3-year-old girl with acute respiratory distress syndrome due to a H1N1 2009 influenza virus infection was complicated by necrotizing pneumonia was successfully treated with extracorporeal membrane oxygenation (ECMO). This is the first reported case in which a pediatric patient was rescued with ECMO during the H1N1 influenza epidemic in Korea in 2009.

Encephalitis Induced by 2009 H1N1 Influenza A

The number of domestic cases of pandemic H1N1 influenza A was elevated in 2009. The common clinical symptoms associated with H1N1 influenza include respiratory symptoms such as cough, sore throat, rhinorrhea, fever, chills, myalgia, and fatigue. Gastrointestinal symptoms are relatively common. H1N1 influenza A infection brings about neurological symptoms in rare cases. However, there are few reports about H1N1 influenza A infection with neurological manifestations. We recently experienced an H1N1 influenza A patient who presented with disturbed mental status, seizures, and focal changes on brain magnetic resonance imaging, associated with infection.

A Case of Pandemic 2009 H1N1 Influenza A Manifestation as Apical Ballooning Syndrome

Critical ill patients with pandemic 2009 H1N1 influenza A are associated with mortality, including cardiovascular, respiratory and renal dysfunction. Understanding of risk factor and clinical manifestation that suggest a higher mortality can recognize high risk patients earlier. There are many reports for severe acute respiratory distress syndrome, multiple organ failure and renal failure with pandemic 2009 H1N1 influenza A. But cardiovascular disease with pandemic 2009 H1N1 influenza A remains unknown. This is the report of pandemic 2009 H1N1 influenza A association with apical balloning syndrome.

2009H1N1 Infection in a 1-day-old neonate.

A full-term female neonate was delivered with meconium stained amniotic fluid by cesarean section by a 2009H1N1 positive 22-year-old second gravida mother, who developed symptoms 8 days prior to delivery. The neonate was completely and immediately isolated from the mother after delivery. Oseltamivir was started at birth to the neonate who had a potential possibility of 2009H1N1 infection. At 5 hours of life, the neonate developed respiratory distress. The neonate's throat swab sent for 2009H1N1 by real-time polymerase chain reaction (RT-PCR) assay was positive. The neonate required oxygen by hood for 3 days and made an uneventful recovery. The mother developed acute respiratory distress syndrome after delivery, requiring ventilatory care for 14 days and was discharged after 25 days stay in hospital. 2009H1N1 infection, although rare, needs a high index of suspicion and prompt therapy in neonates. Clinicians should be alert about the possibility of perinatal transmission of 2009H1N1.