2009 pandemic influenza A (H1N1) in critically ill children in Cincinnati, Ohio.

OBJECTIVE: To compare the clinical features, management, and outcome of critically ill children with H1N1 to children with seasonal influenza from the previous three influenza seasons. DESIGN: The overall number of hospitalizations and the proportion cared for in the pediatric intensive care unit during the H1N1 epidemic period and the three previous influenza seasons (2007-2009) were determined. Medical records of patients admitted to the pediatric intensive care unit with H1N1 and seasonal influenza infection were reviewed. SETTING: Cincinnati Children's Hospital Medical Center, a large, 523-bed hospital located in Cincinnati. PATIENTS: Hospitalized children with laboratory-confirmed seasonal or H1N1 infection. MEASUREMENTS: Study variables included demographic data (age, gender), clinical factors (weight, Pediatric Risk of Mortality III scores, presenting signs and symptoms, comorbid conditions), management (length of mechanical ventilation, other treatments, including high-frequency oscillatory ventilatory support, inhaled nitric oxide, or extracorporeal membrane oxygenation), and outcome (overall and pediatric intensive care unit length of stay and mortality). MAIN RESULTS: Overall, 312 children were hospitalized with H1N1 and 222 with seasonal influenza from the three previous seasons. Children with H1N1 infection were significantly less likely to require pediatric intensive care unit care compared to children with seasonal influenza infection (14% vs. 24%, p = .02). Compared to children with seasonal influenza, children in the pediatric intensive care unit with H1N1 were older (median age in months 107 vs. 68, p = .05) and significantly more likely to have comorbid conditions (64% vs. 40%, p = .03), especially respiratory conditions. While there were no significant differences in severity of illness by Pediatric Risk of Mortality III scores or pediatric intensive care unit length of stay, children with H1N1 were significantly less likely to have acute respiratory failure (p = .04) or die compared to children with seasonal influenza infection (p = .03). CONCLUSIONS: In contrast to other studies, we found that critically ill children with H1N1 had a significantly lower morbidity and mortality compared to children with seasonal influenza.

Estimating the rotavirus hospitalization disease burden and trends, using capture-recapture methods.

BACKGROUND: Rotavirus surveillance is needed to provide estimates of disease burden and to evaluate the effect of vaccination programs. Our objective was to use capture-recapture methods to estimate rotavirus hospitalization rates and to examine trends over time. METHODS: Children <3 years of age residing in Hamilton County, Ohio hospitalized with acute gastroenteritis, and laboratory-confirmed rotavirus between 1997 and 2008 were identified through 2 independent surveillance systems: an active system with prospective enrollment of children admitted with acute gastroenteritis and a passive system of children identified by rotavirus testing as part of their usual medical care. Capture-recapture methods compared cases from both systems to estimate the number of missed cases from either system. Using census data for Hamilton County, rates per 10,000 with 95% confidence intervals (CI) for rotavirus hospitalizations were estimated. RESULTS: Overall, 486 cases were identified using active surveillance and 244 using passive surveillance, with 127 cases captured by both. Using capture-recapture methods, the overall rate in children <3 years old was 26.9/10,000; CI: 24.1, 30.6. Rates varied by year: highest in 1998 (48.1/10,000; CI: 32.4, 92.2) and lowest in 2008 (3.2/10,000; CI: 2.1, 6.1) after rotavirus vaccine introduction. Among children <5 years old, rates were highest in <3-month-old children (51.8/10,000; CI: 39.4, 75.1) and lowest in older age groups: 24 to 35 months (20.5/10,000; CI: 14.7, 30.3) and 36 to 59 months (4.1/10,000; CI: 2.9, 7.2). Rates from capture-recapture methods and adjusted active system were comparable. CONCLUSIONS: Capture-recapture methods were a useful tool to estimate rotavirus disease burden and to monitor trends, especially in the era of rotavirus immunization.

Hepatitis A in internationally adopted children: screening for acute and previous infections.

OBJECTIVE: The goal was to determine the prevalence of acute hepatitis A virus (HAV) infection and immunity among internationally adopted children. METHODS: Children seen at the International Adoption Center between September 25, 2006, and September 30, 2008, and were screened for HAV within 4 months after their arrival in the United States were eligible for the study. The age- and country-specific prevalence of acute HAV infection and immunity were determined. RESULTS: Overall, 288 children underwent HAV serological testing. Of the 279 with total HAV serological results, 29% had positive findings. Immunity varied according to region and country. The prevalence was lowest among children born in Asia/Pacific Rim region (17%) and highest among children born in Africa (72%). Only 13% of children <2 years of age were immune, compared with 80% of children 12 to 17 years of age (P = .002). Increasing age and birth region were associated independently with immunity. Positive HAV immunoglobulin M test results were found for 3 (1%) of 270 children; all were without symptoms. Their ages were 18, 27, and 41 months, and they were born in Kazakhstan, Russia, and the Latin America/Caribbean region, respectively. The father of 1 child developed HAV infection after arriving home. CONCLUSIONS: HAV immunity among internationally adopted children varied according to age and country of origin; 1% had acute infections. HAV screening is useful for determination of the need for HAV immunization and for prevention of transmission to family members and close contacts.

Underestimates of intussusception rates among US infants based on inpatient discharge data: implications for monitoring the safety of rotavirus vaccines.

BACKGROUND: Because a previous rotavirus vaccine was associated with intussusception, new rotavirus vaccines are monitored postlicensure for any such association. Accurate background intussusception rates are needed to determine whether the number of cases observed after vaccination exceeds that expected by chance. Previously, intussusception rates were obtained from inpatient discharge databases. We sought to determine the rate of intussusception among infants managed only with short-stay or emergency department care. METHODS: Intussusception cases occurring in infants were identified retrospectively at 3 children's hospitals from January 2001 through March 2006, a period without rotavirus vaccine use, by a search of discharge, billing, and radiology databases for International Classification of Diseases, Ninth Revision, Clinical Modification code 560.0 (intussusception) and procedure codes and by review of medical records. RESULTS: Of 156 infants with intussusception fulfilling Brighton level 1 criteria, 81 (52%) were billed as inpatients, 68 (44%) as short-stay patients, and 7 (4%) as emergency department patients only. The use of only inpatients assigned code 560.0 underestimated the total number of level 1 cases at the hospitals by 44%. The mean annual intussusception rate for the hospitals' catchment counties was 49.3 cases per 100,000 live births (inpatient cases: 27.1 cases per 100,000 live births; short-stay or emergency department cases: 22.3 cases per 100,000 live births). CONCLUSIONS: Intussusception rates based solely on inpatient discharge databases could underestimate the true incidence of level 1 intussusception by >40%. Background rates used for assessment of risk after vaccination should account for cases managed only with short-stay or emergency department care.