Following these two important clinical trials, the GSK vaccine (HAVRIX) and the MSD vaccine (VAQTA) were licensed in the mid-1990s in the United States and worldwide. Another HAV vaccine containing attenuated inactivated HAV suspended with virosomes as an adjuvant (which is currently unavailable) was developed in Switzerland and tested successfully in Nicaragua.71
Single-Dose Hepatitis A Immunization: 7.5-Year Observational Pilot Study in Nicaraguan Children to Assess Protective Effectiveness and Humoral Immune Memory Response