The immunological response of Thai infants to haemophilus influenzae type B polysaccharide-tetanus conjugate vaccine co-administered in the same syringe with locally produced diphtheria-tetanus-pertussis vaccine.

OBJECTIVE: Comparing the immunogenicity and reactogenicity of three vaccine combinations. These were GlaxoSmithKline Biologicals' (GSK) Haemophilus influenzae type b vaccine (Hib-TT, Hiberix) administered with the local Government Pharmaceutical Organization's (GPO) diphtheria-tetanus-pertussis whole cell (DTPw) vaccine, Hib-TT mixed with GPO's DTPw vaccine, or Hib-IT mixed with GSKs' DTPw vaccine (Tritanrix). MATERIAL AND METHOD: An open, randomized, controlled, single center study of three hundred and sixty infants. They were randomized into three groups to receive either Hib-TT Hiberix mix with GPOs' DTPw vaccine (group 1), Hib-TT mixed with GPO's DTPw vaccine (group 2), or Hib-TT mixed with GSKs' DTPw vaccine (Tritanrix; group 3) at two, four and six months of age. RESULT: One month after the third dose, all subjects had antibodies level against Hib polyribosylribitol phosphate (PRP) > or = 0.15 microg/ml. All 11 subjects except two (in group 2) had anti-PRP levels > or = 1.0 microg/ml. The geometric mean concentrations were similar in all three groups. Over 96% of the subjects in all three groups demonstrated an immunological response to diphtheria, tetanus, and pertussis antigens. There was no diference among the three groups in terms of severe local reaction and fever. CONCLUSION: The present study showed that the combined vaccines produced an effective antibody response with no increase in reactogenicity compared to separately administrated vaccines.

Dengue vaccine.

Dengue is an expanding health problem. About two-fifths of the world population are at risk for acquiring dengue with 50-100 million cases of acute febrile illness yearly including about 500,000 cases of DHF/DSS. No antiviral drugs active against the flavivirus exist. Attempts to control mosquito vector has been largely unsuccessful. Vaccination remains the most hopeful preventive measure. Dengue vaccine has been in development for more than 30 years, yet none has been licensed. The fact that enhancing antibody from previous infection and high level of T cell activation during secondary infection contribute to immunopathology of DHF, the vaccine must be able to induce protective response to four dengue serotypes simultaneously. Inactivated vaccine is safe but needs a repeated booster thus, development is delayed. Tetravalent live attenuated vaccine and chimeric vaccine using yellow fever or dengue viruses as a backbone are being carried out in human trials. DNA vaccine and subunit vaccine are being carried out in animal trials.

Quantification of HIV-1 RNA load by one-tube-one-step RT PCR and real time PCR assay with TaqMan probe.

OBJECTIVES: To develop a less expensive assay to calculate HIV-1 viral load for use in resource-limited countries. MATERIAL AND METHOD: An In-house One-tube-one-step Viral Load Assay (IOVA) was developed by using real-time PCR-based with TaqMan probe. Primers and probe were designed from the conserved region of sequences from all HIV subtypes. A standard curve was generated from reference virus in various dilutions. IOVA was applied on 105 HIV-positive and 25 HIV-negative samples and compared with the results from ROCHE AMPLICLOR. RESULTS: IOVA measured HIV RNA in the samples ranging from 125 to 2 x 10(6) copies/mL. The coefficient of variation of intra- and inter-assay ranged from 0.68% to 7.89%. The sensitivity, specificity, positive and negative predictive values were 92%, 100%, 100% and 79.5% respectively. The parallel quantitative analysis showed high correlation (r=0.95) between IOVA and AMPLICOR. CONCLUSION: A new HIV-1 viral load assay was developed and validated. It was reliable and less expensive.