Virtually anyone who is not vaccinated will get the disease if they ingest the virus. No, although it is usually self limiting without lifetime consequences. About 143,000 people in the United States get this disease each year. Although it isn't usually life threatening, Hepatitis A can last several weeks with relapses occuring in about one out of five cases. Symptoms may continue on and off for 15 months.
Some patients are sick enough to require hospitalization.
Anyone who has not had the disease or who has not had a successful series of vaccinations. 4 weeks to 6 months. The time you are at the most risk is adolescence and young adulthood. There is a concerted effort to eradicate Hepatitis B through immunization of newborns in the United States and several other countries. Not included in that group, however, is a huge population of adolescents who are entering the period in their lives when they will become sexually active.