Umesh D. Parashar

Background: Diarrhea is a major cause of morbidity and mortality, yet incidence and etiology data are limited. We conducted laboratory-based diarrhea surveillance in Guatemala. Methods: A diarrhea case was defined as ≥3 loose stools in a 24-h period in a person presenting to the surveillance facilities. Epidemiologic data and stool specimens were collected. Specimens were tested for bacterial, parasitic, and viral pathogens. Yearly incidence was adjusted for healthcare seeking behaviors determined from a household survey conducted in the surveillance catchment area. Results: From November 2008 to December 2012, the surveillance system captured 5331 diarrhea cases; among these 1381 (26%) had specimens tested for all enteric pathogens of interest. The adjusted incidence averaged 659 diarrhea cases per 10,000 persons per year, and was highest among children aged < 5 years, averaging 1584 cases per 10,000 children per year. Among 1381 (26%) specimens tested for all the pathogens of interest, 235 (17%) had a viral etiology, 275 (20%) had a bacterial, 50 (4%) had parasites, and 86 (6%) had co-infections. Among 827 (60%) specimens from children aged < 5 years, a virus was identified in 196 (23%) patients; 165 (20%) had norovirus and 99 (12%) rotavirus, including co-infections. Among 554 patients aged ≥5 years, 103 (19%) had a bacterial etiology, including diarrheagenic Escherichia coli in 94 (17%) cases, Shigella spp. in 31 (6%), Campylobacter spp. in 5 (1%), and Salmonella spp. in 4 (1%) cases. Detection of Giardia and Cryptosporidium was infrequent (73 cases; 5%). Conclusions: There was a substantial burden of viral and bacterial diarrheal diseases in Guatemala, highlighting the importance of strengthening laboratory capacity for rapid detection and control and for evaluation of public health interventions.

Introduction: In 1998, the first licensed rotavirus vaccine was associated with intussusception, an unexpected adverse event, following reports of this condition to an adverse event reporting system. This rotavirus vaccine was withdrawn from the market and newer rotavirus vaccines have been extensively evaluated for an association with intussusception. Areas covered: We review the different study designs that have been used both pre- and post-licensure to evaluate the association of rotavirus vaccines with intussusception and discuss the pros and cons of each design. Each of these study designs has their own strengths and weaknesses and the choice of the design often depends on the objective and the timing of the study and the resources available. For post-licensure monitoring of rotavirus vaccines, the self-controlled case-series design has become the most commonly used design to monitor this association. Expert opinion: Use of this common study design has enabled comparison of findings across diverse settings. As new rotavirus vaccines enter the market, use of the self-controlled case-series design will enable examination of this association in a timely manner.

Background: Diarrhea-associated deaths among US children increased from the mid-1980s through 2006, particularly among infants. Understanding risk factors for diarrhea-associated death could improve prevention strategies. Methods: Records of singleton infants with diarrhea listed anywhere on the death certificate were selected from the US Linked Birth/Infant Death data for the period, 2005 to 2007; characteristics of these infants were compared with those of infants who survived their first year. Results: During 2005 to 2007, 1087 diarrhea-associated infant deaths were reported; 86% occurred among low birth weight (LBW, P < 0.0001). The most common codiagnoses for diarrhea-associated death among LBW and NBW infants were sepsis (26%) and volume depletion (20%), respectively. Among LBW infants, 97% of diarrhea-associated deaths occurred in inpatient settings, whereas 27% of NBW infant deaths occurred in outpatient settings and 5.3% in the decedent’s home. Male sex, black race, unmarried status and low 5-minute Apgar score (<7) increased mortality odds among LBW infants whereas, among NBW infants, low 5-minute Apgar score, black race, young maternal age (<25 years) and high birth order (third or more) increased mortality odds. Conclusions: Efforts to reduce diarrhea-associated morality should focus on understanding and improving management of diarrhea in vulnerable LBW infants. For prevention of diarrhea-associated deaths in NBW infants, educating mothers who fit the high-risk profile regarding home hydration therapy and timely access to medical treatment is important.

Routine vaccination of U.S. infants with pentavalent rotavirus vaccine (RV5) began in 2006.

BackgroundRotavirus causes approximately one-third to one-half (55,000–70,000 hospitalizations per year) of hospitalizations for acute gastroenteritis (AGE) among US children MethodsThe mean number of hospitalizations for AGE by calendar month among US children was determined using the National Hospital Discharge Survey from the period 1993–2005. From these baseline prevaccine estimates, we forecasted the effect of vaccine in reducing the number of hospitalizations for rotavirus disease and AGE during 2006–2015 with use of estimates of vaccine effectiveness and uptake ResultsDuring 2006–2015, ∼313,000 (45%) of an estimated 703,190 hospitalizations for rotavirus disease would be directly prevented by vaccination. A significant reduction in the number of hospitalizations for AGE should be detectable among infants aged 0–11 months during the first quarter of 2009, followed by children aged 12–23 months during 2010, and all children ConclusionsVaccination is expected to substantially reduce the health burden of hospitalizations for rotavirus disease among US children during 2006–2015, and the impact of vaccination based on direct protective effects alone was expected to first occur for hospitalizations for AGE among infants during winter 2009

Rotavirus is the most common cause of severe gastroenteritis in infants and young children worldwide. Before initiation of the rotavirus vaccination program in the United States in 2006, approximately 80% of U.S. children had rotavirus gastroenteritis by age 5 years. Each year during the 1990s and early 2000s, rotavirus resulted in approximately 410,000 physician visits, 205,000272,000 emergency department visits, and 55,00070,000 hospitalizations among U.S. infants and children, with total annual direct and indirect costs of approximately $1 billion. In February 2006, a live, oral, human-bovine reassortant rotavirus vaccine (RotaTeq(R) [RV5]) was licensed as a 3-dose series for use among U.S. infants for the prevention of rotavirus gastroenteritis, and the Advisory Committee on Immunization Practices (ACIP) recommended routine use of RV5 among U.S. infants (CDC. Prevention of rotavirus gastroenteritis among infants and children: recommendations of the Advisory Committee on Immunization Practices [ACIP]. MMWR 2006;55[No. RR-12]). In April 2008, a live, oral, human attenuated rotavirus vaccine (Rotarix(R) [RV1]) was licensed as a 2-dose series for use among U.S. infants, and in June 2008, ACIP updated its rotavirus vaccine recommendations to include use of RV1. This report updates and replaces the 2006 ACIP statement for prevention of rotavirus gastroenteritis. ACIP recommends routine vaccination of U.S. infants with rotavirus vaccine. RV5 and RV1 differ in composition and schedule of administration. RV5 is to be administered orally in a 3-dose series, with doses administered at ages 2, 4, and 6 months. RV1 is to be administered orally in a 2-dose series, with doses administered at ages 2 and 4 months. ACIP does not express a preference for either RV5 or RV1. The recommendations in this report also address the maximum ages for doses, contraindications, precautions, and special situations for the administration of rotavirus vaccine.

In 2006, a new rotavirus vaccine (RotaTeq) was licensed in the US and recommended for routine immunization of all US infants. Because a previously licensed vaccine (Rotashield) was withdrawn from the US for safety concerns, identifying barriers to uptake of RotaTeq will help develop strategies to broaden vaccine coverage.