Angela P. Campbell

Japanese encephalitis virus remains an important cause of encephalitis in Thailand

BACKGROUND Japanese encephalitis virus (JEV) is endemic in Thailand and prevention strategies include vaccination, vector control, and health education. METHODS Between July 2003 and August 2005, we conducted hospital-based surveillance for encephalitis at seven hospitals in Bangkok and Hat Yai. Serum and cerebrospinal (CSF) specimens were tested for evidence of recent JEV infection by immunoglobulin M (IgM) enzyme-linked immunosorbent assay (ELISA) and a plaque reduction neutralization test (PRNT). RESULTS Of the 147 patients enrolled and tested, 24 (16%) had evidence of acute flavivirus infection: 22 (15%) with JEV and two (1%) with dengue virus. Of the 22 Japanese encephalitis (JE) cases, 10 (46%) were aged ≤ 15 years. The median length of hospital stay was 13 days; one 13-year-old child died. Ten percent of encephalitis patients enrolled in Bangkok hospitals were found to have JEV infection compared to 28% of patients enrolled in hospitals in southern Thailand (p < 0.01). Four (40%) of the 10 children with JE were reported as being vaccinated. CONCLUSIONS JEV remains an important cause of encephalitis among hospitalized patients in Thailand. The high proportion of JE among encephalitis cases is concerning and additional public health prevention efforts or expanded vaccination may be needed.

Increased Antiviral Treatment Among Hospitalized Children and Adults With Laboratory-Confirmed Influenza, 2010-2015

(See the Editorial Commentary by Martin on pages 368–9.)Using population-based surveillance data, we analyzed antiviral treatment among hospitalized patients with laboratory-confirmed influenza. Treatment increased after the influenza A(H1N1) 2009 pandemic from 72% in 2010–2011 to 89% in 2014–2015 (P < .001). Overall, treatment was higher in adults (86%) than in children (72%); only 56% of cases received antivirals on the day of admission.

Infectious Causes of Encephalitis and Meningoencephalitis in Thailand, 2003-2005

Although many causes were identified, most remain unknown.

Use of Influenza Antiviral Medications Among Outpatients at High Risk for Influenza-Associated Complications During the 2013–2014 Influenza Season

During the 2013-2014 influenza season, we analyzed data from 6004 outpatients aged ≥6 months with acute respiratory illness (ARI). Among the 2786 ARI patients at higher risk for influenza complications, 835 (30%) presented to care ≤2 days from symptom onset; among those, 126 (15%) were prescribed an antiviral medication.

Commentary: A Historical Review of Centers for Disease Control and Prevention Antiviral Treatment and Postexposure Chemoprophylaxis Guidance for Human Infections With Novel Influenza A Viruses Associated With Severe Human Disease

Human infections with novel influenza A viruses are of global public health concern, and antiviral medications have a potentially important role in treatment and prevention of human illness. Initial guidance was developed by the U.S. Centers for Disease Control and Prevention after the emergence of human infections with avian influenza A(H5N1) and has evolved over time, with identification of influenza A(H7N9) virus infections in humans, as well as detection of avian influenza viruses in birds in the United States. This commentary describes the historical context and current guidance for the use of influenza antiviral medications for treatment and post-exposure chemoprophylaxis of human infections with novel influenza A viruses associated with severe human illness, or with the potential to cause severe human disease, and provides the scientific rationale behind current recommendations.

Clinical Features and Outcomes of Immunocompromised Children Hospitalized With Laboratory-Confirmed Influenza in the United States, 2011–2015

Background Existing data on the clinical features and outcomes of immunocompromised children with influenza are limited. Methods Data from the 2011-2012 through 2014-2015 influenza seasons were collected as part of the Centers for Disease Control and Prevention (CDC) Influenza Hospitalization Surveillance Network (FluSurv-NET). We compared clinical features and outcomes between immunocompromised and nonimmunocompromised children (<18 years old) hospitalized with laboratory-confirmed community-acquired influenza. Immunocompromised children were defined as those for whom ≥1 of the following applies: human immunodeficiency virus/acquired immunodeficiency syndrome, cancer, stem cell or solid organ transplantation, nonsteroidal immunosuppressive therapy, immunoglobulin deficiency, complement deficiency, asplenia, and/or another rare condition. The primary outcomes were intensive care admission, duration of hospitalization, and in-hospital death. Results Among 5262 hospitalized children, 242 (4.6%) were immunocompromised; receipt of nonsteroidal immunosuppressive therapy (60%), cancer (39%), and solid organ transplantation (14%) were most common. Immunocompromised children were older than the nonimmunocompromised children (median, 8.8 vs 2.8 years, respectively; P < .001), more likely to have another comorbidity (58% vs 49%, respectively; P = .007), and more likely to have received an influenza vaccination (58% vs 39%, respectively; P < .001) and early antiviral treatment (35% vs 27%, respectively; P = .013). In multivariable analyses, immunocompromised children were less likely to receive intensive care (adjusted odds ratio [95% confidence interval], 0.31 [0.20-0.49]) and had a slightly longer duration of hospitalization (adjusted hazard ratio of hospital discharge [95% confidence interval], 0.89 [0.80-0.99]). Death was uncommon in both groups. Conclusions Immunocompromised children hospitalized with influenza received intensive care less frequently but had a longer hospitalization duration than nonimmunocompromised children. Vaccination and early antiviral use could be improved substantially. Data are needed to determine whether immunocompromised children are more commonly admitted with milder influenza severity than are nonimmunocompromised children.

Antiviral treatment for outpatient use during an influenza pandemic: a decision tree model of outcomes averted and cost-effectiveness

Abstract Background Many countries have acquired antiviral stockpiles for pandemic influenza mitigation and a significant part of the stockpile may be focussed towards community-based treatment. Methods We developed a spreadsheet-based, decision tree model to assess outcomes averted and cost-effectiveness of antiviral treatment for outpatient use from the perspective of the healthcare payer in the UK. We defined five pandemic scenarios—one based on the 2009 A(H1N1) pandemic and four hypothetical scenarios varying in measures of transmissibility and severity. Results Community-based antiviral treatment was estimated to avert 14–23% of hospitalizations in an overall population of 62.28 million. Higher proportions of averted outcomes were seen in patients with high-risk conditions, when compared to non-high-risk patients. We found that antiviral treatment was cost-saving across pandemic scenarios for high-risk population groups, and cost-saving for the overall population in higher severity influenza pandemics. Antiviral effectiveness had the greatest influence on both the number of hospitalizations averted and on cost-effectiveness. Conclusions This analysis shows that across pandemic scenarios, antiviral treatment can be cost-saving for population groups at high risk of influenza-related complications.

Respiratory Syncytial Virus-Associated Hospitalizations in Young Children in the United States, 2015–2016

Abstract Background Respiratory syncytial virus (RSV) is a major cause of severe acute respiratory illness (ARI) among young children. With several vaccines and immunoprophylaxis agents for RSV currently in development, updated estimates of severe RSV disease in young children in the United States (US) are needed. Methods Prospective active surveillance for hospitalized ARI was conducted from 11/1/2015 to 6/30/2016 among children <5 years of age at seven pediatric hospital sites participating in the New Vaccine Surveillance Network. Demographic and clinical information for enrolled subjects were gathered through parent interviews and medical chart reviews. Mid-turbinate nasal and throat flocked swabs (combined for testing when available) and/or tracheal aspirates (when pertinent) were collected for respiratory pathogen testing. Specimens were tested for RSV using molecular diagnostic assays at each site. Results In preliminary data analyses, 2,948 hospitalized children with a median age of 11 months were enrolled during the study period, of whom 1,030 (35%) tested positive for RSV. Most RSV-detections occurred in children <2 years of age (87%; n = 893), with 340 (33%) RSV-positive children aged 0–2 months, 184 (18%) aged 3–5 months, 174 (17%) aged 6–11 months, and 195 (19%) aged 12–23 months. The majority of RSV-positive children (75%; n = 776) had no chart-documented comorbid conditions. Among 893 RSV-positive children <2 years of age, 161 (18%) reported a history of preterm birth, with 99 (11%) reporting birth at 34–36 weeks gestational age (WGA), 33 (4%) at 30–33 WGA, 20 (2%) at <30 WGA, and 9 (1%) with no further gestational age information available. Among all RSV-positive subjects, the median length of stay was 2 days; 706 (69%) received supplemental oxygen during hospitalization, 226 (22%) were admitted to an intensive care unit, and 28 (3%) required mechanical ventilation. Conclusion During the 2015–16 season, RSV was associated with one-third of ARI hospitalizations in young children, the majority of which occurred in children aged <2 years. Most RSV-positive children were previously healthy, and nearly one fifth of those <2 years of age reported a history of preterm birth. RSV continues to be a major cause of morbidity among young children in the US. Disclosures N. B. Halasa, sanofi pasteur: Research Contractor, Research support; Astra Zeneca: Research Contractor, Grant recipient; J. Englund, Gilead: Consultant and Investigator, Research support; Chimerix: Investigator, Research support; Alios: Investigator, Research support; Novavax: Investigator, Research support; MedImmune: Investigator, Research support; GlaxoSmithKline: Investigator, Research support; J. V. Williams, Quidel: Scientific Advisor, Consulting fee; GlaxoSmithKline: Scientific Advisor, Consulting fee; F. M. Munoz, Novavax: Investigator, Research support; Regeneron: Investigator, Research support; GSK: Investigator, Research support