Systemic antibody response to nano-size calcium phospate biocompatible adjuvant adsorbed HEV-71 killed vaccine

PURPOSE: Since 1980s, human enterovirus-71 virus (HEV-71) is one of the common infectious disease in Asian Pacific region since late 1970s without effective commercial antiviral or protective vaccine is unavailable yet. The work examines the role of vaccine adjuvant particle size and the route of administration on postvaccination antibody response towards HEV-71 vaccine adsorbed to calcium phosphate (CaP) adjuvant. MATERIALS AND METHODS: First, CaP nano-particles were compared to a commercial micro-size and vaccine alone. Secondly, intradermal reduced dosage was compared to the conventional intramuscular immunization. Killed HEV-71 vaccines adsorbed to CaP nano-size (73 nm) and commercial one of micro-size (1.7 microm) were administered through intradermal, intramuscular, rabbits received vaccine alone and unvaccinated animals. RESULTS: CaP nano-particles adsorbed HEV-71 vaccine displayed higher antibody than the micro-size or unadsorbed vaccine alone, through both parenteral immunization routes. Moreover, the intradermal route (0.5 microg/mL) of 0.1-mL volume per vaccine dose induced equal IgG antibody level to 1.0-mL intramuscular route (0.5 microg/mL). CONCLUSION: The intradermal vaccine adsorbed CaP nano-adjuvant showed safer and significant antibody response after one-tenth reduced dose quantity (0.5 microg/mL) of only 0.1-mL volume as the most suitable protective, cost effective and affordable formulation not only for HEV-71; but also for developing further effective vaccines toward other human pathogens.

Occupational Hazards and HBV infection among health care workers in public teaching hospitals in Khartoum State, Sudan: a multiple discriminant analysis

Infection with HBV leads to a wide spectrum of liver injury. It ranges from acute self-limited infection and fulminant hepatitis to chronic hepatitis. To examine the prevalence of sero-epidemiologic markers of hepatitis B virus and to identify the risk factors of exposure to HBV among health care workers in Public Teaching Hospitals in Khartoum State, Sudan; in 2004. The study was a cross sectional, facility-based study. It was conducted on stratified two-stage cluster sampling of 843 subjects. The study adopted multivariate statistical approach, using Multiple Discriminant Analysis [MDA] and some non-parametric tests. Infection rate measured by Anti-HB core, carrier rate measured by HBs Ag, and a profile of high infectivity rate measured by HBe Ag was found to be high; while immunity rate measured by Anti-HBs was found to be low. Needle stick injury, contaminated sharp instruments injury and exposure to blood are the most significant occupational variables related to infection rate of HBV. Contaminated sharp instruments injury and exposure to blood, are the most significant occupational variables related to carrier rate. Date of needle stick injury, incidence and date of contaminated sharp instruments injury, incidence and date of exposure to blood have significant relation to immunity rate against HBV infection. The prevalence rate of HBV markers among HCWs in Public Teaching Hospitals in Khartoum State, Sudan, differs according to occupational hazard factors. With the exception of the HBeAg, seroprevalence of all HBV markers was found to be significantly correlated with occupational hazards [P<0.05]