Familial clustering of hepatitis B virus infections and prevention of perinatal transmission by immunization with a reduced number of doses in an area of intermediate endemicity (Tunisia)

A Serological Survey of Selected Papua New Guinea Blood Donors for Hepatitis B and Related Co-Infections

Hepatitis B virus (HBV) infection is a serious problem and earlier studies in Papua New Guinea have reported a high prevalence of hepatitis B virus infection. These studies were undertaken using insensitive tests and before an expanded immunization program. The current HBV status is therefore uncertain. A retrospective study to investigate the HBV status was carried out using blood donor data at Nonga General Hospital, East New Britain Province, Papua New Guinea, from January 2003 to December 2018. Additional data for Human Immunodeficiency Virus, syphilis and hepatitis C virus were also collected. Data were analysed using NCSS statistical software. The mean hepatitis B antigen (HBsAg) sero-prevalence was 21% for the period of study and showed a downward trend over the period of the study, which may reflect the effect of the extended immunization program. HBsAg prevalence in male donors (23%) was significantly higher than females (16%). Donors living in Pomio district had a significantly lower proportion of sero-positive HBsAg donors (7%) than Gazelle (22%), Kokopo (22%) and Rabaul (20%), which was attributed to this district's geographical isolation. Ethnically, Pomios donors (8%) had significantly lower HBsAg prevalence than the Taulils, (29%), Bainings (21%) and Tolais (21%). Fifteen to nineteen year olds (23%) were the predominant age group affected, and vertical or perinatal transmission was probably the primary transmission route. Our findings call for greater awareness on the part of public policy makers and should be considered when planning future public health campaigns.

A novel hepatitis B virus subgenotype, D7, in Tunisian blood donors

Tunisia is a medium-level epidemic country for hepatitis B virus (HBV). This study characterizes, for the first time, full genome HBV strains from Tunisia. Viral load quantification and phylogenetic analyses of full genome or pre-S/S sequences were performed on 196 hepatitis B surface antigen (HBsAg)-positive plasma samples from Tunisian blood donors. The median viral load was 64.65 IU ml(-1) (range<5-7.7x10(8) IU ml(-1)) and 89% of samples had viral loads below 10,000 IU ml(-1). Fifty-nine strains formed a novel subgenotype D7, 41 strains clustered in subgenotype D1, seven strains in subgenotype A2 and one strain in genotype C. The novel subgenotype D7 was defined by maximum Bayesian posterior probability, a genetic divergence from other HBV/D subgenotypes by >4% and a stronger HBV/E signal in the X to core genes than subgenotype D1. In conclusion, HBV/D is dominant in asymptomatic Tunisian HBsAg carriers and a novel subgenotype, D7, was the most common subgenotype found in this population.

A review of the design of vaccine efficacy trials and a proposal for the design of the VA Cooperative Study of Active Immunotherapy of HIV Infection

We review the design of vaccine trials based on a search of the medical literature over the past four years, and present the proposed design of a therapeutic HIV vaccine efficacy study by the Department of Veterans Affairs Cooperative Studies Program. We explore the reasons for the atypical design of many vaccine trials, particularly the analysis of efficacy and how it differs from the more usual intent-to-treat analysis used in nonvaccine trials.