San Francisco will play host to a public meeting on smallpox vaccines this Thursday. Vaccine experts this week will ask Americans if the nation should change its smallpox immunization policy of giving no vaccinations unless smallpox reappears. In San Francisco and New York on Thursday, vaccine advisers to the Centers for Disease Control and Prevention will hear if the public wants a different strategy, such as allowing voluntary vaccinations. It´s part of a series of efforts to modernize defenses against smallpox. Later this month, Army virologists will begin injecting monkeys with deadly virus with the goal of creating a way to study if new medications could battle smallpox. On June 20th in Atlanta, the advisers will offer the government a recommendation.