Prevalence and genotype distribution of JC polyomavirus in urine from patients with hematological malignancies in Vietnam.

JC virus (JCV) causes progressive multifocal leukoencephalopathy in immunocompromised patients. The prevalence and genotype patterns of JCV vary between different geographical regions. This study was done to investigate the prevalence and genotype distribution of JCV in patients with hematological malignancies in Vietnam. A total of 48 urine samples were collected from patients with hematological malignancies. DNA was extracted and detection of JCV was by nested-polymerase chain reaction. Sequence analysis was obtained and a phylogenetic tree was constructed for genotyping of JCV. Twenty-seven (56.25%) urine samples tested positive for JCV. JCV genotype 7 was only observed in this study. Subtype analysis showed that JCV subtype 7A was the most commonly prevalent, followed by 7B1 and 7C1. Other subtypes were not detected in this population. There were no significant differences associated with age, gender, and biochemical parameters between patients with JCV and without JCV excretion in urine. The present study showed a high prevalence of JCV in the urine of patients with hematologic malignancies. The most common genotype found in this population was JCV subtype 7A.

Endemic diphtheria in Ho Chi Minh City; Viet Nam: a matched case-control study to identify risk factors of incidence.

From 1999 to 2004, Ho Chi Minh City (HCMC), Vie Nam reported 401 clinically suspected and 90 laboratory-confirmed diphtheria. To identify risk factors, a matched case-control study was conducted during 2005 and 2006. In total, 88 cases that occurred in 2003 and 2004 and 352 age- and sex-matched controls were studied. No DPT/DT immunisation (odds ratio, 9.9 [95% CI, 1.9-52.3]) and bathing only once a day or less (OR 1.7 [95% CI, 1.0-2.9]) were associated with diphtheria incidence. Estimated vaccine efficacy of three or more DPT/DT doses was 88%. Immunising children with zero-dose status of diphtheria toxoid inoculation, rather than the introduction of booster doses, and the promotion of skin hygiene were considered to be the priority interventions in controlling the endemic diphtheria in HCMC.

Development and characterization of candidate rotavirus vaccine strains derived from children with diarrhoea in Vietnam.

In Vietnam, rotavirus infection accounts for more than one-half of all hospitalizations for diarrhoea among children less than 5 years of age. While new vaccines to prevent rotavirus diarrhoea have been developed and introduced into some countries by multinational manufacturers, the ability for developing countries such as Vietnam to introduce several new and important vaccines into the routine infant immunization schedule may be challenging. In order to be partially self-sufficient in vaccine production, Vietnam has pursued the development of several rotavirus strains as candidate vaccines using isolates obtained from Vietnamese children with diarrhoea. This paper describes the origin, isolation and characterization of 3 human rotavirus strains being considered for further vaccine development in Vietnam. The goal is to prepare a monovalent G1P [8] rotavirus vaccine using one of these strains obtained in Vietnam and naturally attenuated by multiple passages in cell culture. While this is an ambitious project that will require several years' work, we are using the lessons learned to improve the overall quality of vaccine production including the use of Vero cell techniques for the manufacture of other vaccines in Vietnam.