Common-source (e.g., water, restaurant) outbreaks are typical. Infection is common in children in developing countries, reaching 100% incidence , but following infection there is life-long immunity . HAV can be inactivated by: chlorine treatment (drinking water), formalin (0.35%, 37 o C, 72 hours), peracetic acid (2%, 4 hours), beta-propiolactone (0.25%, 1