Safety and immunogenicity of a tetravalent live-attenuated dengue vaccine in flavivirus naive children.

A live-attenuated tetravalent dengue virus (DENV) vaccine candidate has been well tolerated and immunogenic in healthy, US flavivirus naive adult volunteers. We conducted a pilot, safety, and immunogenicity trial of the vaccine candidate in healthy Thai children (6-7 years of age) to prepare for its eventual evaluation in Thai infants. In an uncontrolled, open clinical trial, the investigational vaccine was administered on study Days 0 and 180 to seven volunteers residing in Bangkok without neutralizing antibodies to DENV1-4 or to Japanese encephalitis virus (JEV). Clinical and laboratory safety assessments were completed during the 30 days after each vaccine dose, and immunogenicity was determined at Day 30. In this study, the vaccine was well tolerated with no serious adverse events or alert laboratory values. One volunteer experienced fever (38.2 degrees C, < 2 days) and associated DENV4 vaccine viremia 7 days after Dose 2. One month after Dose 2, six volunteers in the per-protocol analysis exhibited a tetravalent neutralizing antibody response with DENV1-4 geometric mean titers of 55, 475, 350, and 171, respectively. Ten weeks (~75 days) after Dose 2, five of the six volunteers continued to exhibit a tetravalent neutralizing antibody profile; one volunteer's DENV4 PRNT50 titer fell below the assay cut-off (29 --> < 10); (clinicaltrials.gov NCT00384670).

Are women who work in bars, guesthouses and similar facilities a suitable study population for vaginal microbicide trials in Africa?

BACKGROUND: A feasibility study was conducted to investigate whether an occupational at-risk cohort of women in Mwanza, Tanzania are a suitable study population for future phase III vaginal microbicide trials. METHODOLOGY/PRINCIPAL FINDINGS: 1573 women aged 16-54 y working in traditional and modern bars, restaurants, hotels, guesthouses or as local food-handlers were enrolled at community-based reproductive health clinics, provided specimens for HIV/STI and pregnancy testing, and asked to attend three-monthly clinical follow-up visits for 12-months. HIV positive and negative women were eligible to enter the feasibility study and to receive free reproductive health services at any time. HIV prevalence at baseline was 26.5% (417/1573). HIV incidence among 1156 sero-negative women attending at baseline was 2.9/100PYs. Among 1020 HIV sero-negative, non-pregnant women, HIV incidence was 2.0/100PYs, HSV-2 incidence 12.7/100PYs and pregnancy rate 17.8/100PYs. Retention at three-months was 76.3% (778/1020). Among 771 HIV sero-negative, non-pregnant women attending at three-months, subsequent follow-up at 6, 9 and 12-months was 83.7%, 79.6%, and 72.1% respectively. Older women, those who had not moved home or changed their place of work in the last year, and women working in traditional bars or as local food handlers had the highest re-attendance. CONCLUSIONS/SIGNIFICANCE: Women working in food outlets and recreational facilities in Tanzania and other parts of Africa may be a suitable study population for microbicide and other HIV prevention trials. Effective locally-appropriate strategies to address high pregnancy rates and early losses to follow-up are essential to minimise risk to clinical trials in these settings.

Hospital-based surveillance to estimate the burden of rotavirus gastroenteritis among European children younger than 5 years of age.

OBJECTIVES: Rotavirus is the leading cause of acute gastroenteritis requiring hospitalization in young children. Data on the burden of rotavirus gastroenteritis are needed to guide recommendations for rotavirus vaccine use. This study was undertaken to estimate the burden of rotavirus gastroenteritis in European children <5 years of age. METHODS: This prospective, study was conducted in 12 hospitals in France, Germany, Italy, Spain, and the United Kingdom. A sample of all children aged <5 years presenting to emergency departments or hospitalized because of community-acquired acute gastroenteritis was enrolled for parental interview and stool collection. Acute gastroenteritis was defined as diarrhea (>/=3 loose stools per 24 hours) for <14 days. Rotavirus was detected by enzyme-linked immunosorbent assay and typed by reverse-transcriptase polymerase chain reaction. RESULTS: Between February 2005 and August 2006, 3734 children with community-acquired acute gastroenteritis were recruited and retained for analysis (55.9% via the emergency department, 41.8% hospitalized). Of the 2928 community-acquired acute gastroenteritis cases for which stool samples were available, 43.4% were rotavirus-positive by enzyme-linked immunosorbent assay (32.8% emergency department, 56.2% hospitalized). Of these rotavirus gastroenteritis cases 80.9% occurred in children aged <2 years and 15.9% among infants aged <6 months. Acute gastroenteritis was more severe in rotavirus-positive subjects (Vesikari score >/= 11 in 53.3% compared with 31.0% of rotavirus-negative subjects). All 1271 rotavirus-positive strains were genotyped (G1P[8]: 40.3%; G9P[8]: 31.2%; G4P[8]: 13.5%; G3P[8]: 7.1%). CONCLUSIONS: Rotavirus gastroenteritis places high demands on European health care systems, accounting for 56.2% of hospitalizations and 32.8% of emergency department visits because of community-acquired acute gastroenteritis in children aged <5 years. Most community-acquired rotavirus gastroenteritis occurs in children aged <2 years, and a high proportion occurs in infants aged <6 months. Cases were also observed among very young infants <2 months of age. Rotavirus vaccination is expected to have a major impact in reducing morbidity and the pressure on hospital services in Europe.