Safety and Immunogenicity of a Quadrivalent Meningococcal Conjugate Vaccine (MenACYW-DT): A Multicenter, Open-label, Non-randomized, Phase III Clinical Trial.

Objective: To assess the safety and immunogenicity of a quadrivalent meningococcal (groups A,C,Y,W) polysaccharide diphtheria toxoid conjugate vaccine (MenACYW-DT) in India. Design: Open-label, descriptive, non-randomized study. Setting: Three medical college hospitals, one each in New Delhi, Bengaluru and Mumbai, India. Participants: 300 healthy, vaccine-naïve participants (100 children aged 2-11 years, 100 adolescents aged 12-17 years, and 100 adults aged 18-55 years). Intervention: One dose (0.5 mL) of MenACYW-DT administered intramuscularly. Main outcome measures: Serum bactericidal antibody titers against A, C, Y, and W were measured before and after MenACWY-DT vaccination. Safety data were also collected Results: Thirty days post-vaccination, geometric mean titers rose across all serogroups. Most participants had protective titers ≥8 (1/dil) across the four serogroups. The percentage (95% CI) achieving ≥8 (1/dil) in the Adolescent Group was typical – A: 96.9% (91.2%; 99.4%); C: 96.9% (91.2%; 99.4%); Y:100% (96.3%; 100%); W:100% (96.3%; 100%). In general, solicited reactions were mild and short-lived. Unsolicited events were uncommon and unrelated to vaccination. Conclusions: MenACYW-DT was well tolerated and elicited a robust and protective immune response 30 days post-vaccination against meningococcal serogroups A, C, Y, and W-135 in the Indian study participants aged 2-55 years.

Is the skin sensitivity test required for administering equine rabies immunoglobulin.

Background. Rabies immunoglobulins are life-saving in patients with severe exposure to rabies. Despite the high degree of purification of equine rabies immunoglobulin (ERIG), the product inserts still recommend a skin sensitivity test before administration of this heterologous serum. A recent WHO recommendation states that there are no scientific grounds for performing a skin test before administering ERIG because testing does not predict reactions and it should be given irrespective of the result of the test. In this conflicting situation, we assessed the use of the skin sensitivity test in predicting adverse events to ERIG. Methods. The data analysed were from the Antirabies Clinic of the Kempegowda Institute of Medical Sciences Hospital, Bengaluru, India. The period of study was 26 months (June 2008–July 2010). The skin sensitivity test was validated by evaluating its sensitivity, specificity, predictability, falsepositive and false-negative results. Results. A total of 51 (2.6%) adverse events were reported in 31 (1.5%) subjects. Most of these were mild to moderate in nature and subsided without medication. There was no serious adverse event. The sensitivity and specificity of the skin sensitivity test to predict an adverse event was 41.9% and 73.9%, respectively. Conclusion. Our experience with the skin sensitivity test suggests that it may not be required before administering ERIGs, as recommended by WHO.

Boosting effect of purified chick embryo cell rabies vaccine using the intradermal route in persons previously immunized by the intramuscular route or vice versa.

BACKGROUND: At present, in the event of re-exposure to rabies, 2 booster doses are recommended for people who have been previously vaccinated with cell culture rabies vaccines by the conventional intramuscular route. As the intradermal route of vaccination is likely to be introduced in the future, we investigated the immune response to a cell culture rabies vaccine after crossing over from the intramuscular to the intradermal route and vice versa. METHODS: Twenty healthy adult volunteers who had received a primary course of rabies vaccination with purified chick embryo cell rabies vaccine by either the intramuscular (n = 10) or intradermal (n = 10) route received booster vaccination with the same vaccine by the alternative route. The regimen used was 0.1 ml of vaccine by the intradermal route at two sites (deltoid area) for the intramuscular group, or 1 ml of vaccine by the intramuscular route (deltoid muscle) to the intradermal group on days 0 and 3. RESULTS: There was a 15-fold rise in the rabies virus neutralizing antibody response both by the intradermal and intramuscular routes of booster vaccination (p < 0.0001). Thus, the change of route of purified chick embryo cell booster vaccination did not alter the anamnestic immune response to the vaccine. No side-effects were observed after vaccination with either of the routes. CONCLUSION: Purified chick embryo cell vaccine was found to be safe and immunologically efficacious following booster vaccination after cross-over from the intradermal to the intramuscular route and vice versa.