Anonymous Content, a production company whose top investor is Laurene Powell Jobs’s Emerson Collective, has named Darren Walker as president and chief executive.

With tight business restrictions still in place, companies may find it challenging to even assess what opportunities exist for them in the South American nation.

Dr. Kirk Milhoan, a pediatric cardiologist who leads the Advisory Committee on Immunization Practices, said a person’s right to refuse a vaccine outweighed concerns about illness or death from infectious diseases.