Health authorities this week confirmed that 38-year-old Watila Santos died from the illness on March 11.
Authorities are investigating possible cases involving four relatives of Santos, including a 13-year-old and a 9-year-old.
In the city center and rural areas of Casimiro de Abreu, about 93 miles (150 kilometers) from Rio de Janeiro, a large tent has been set up to vaccinate people. Authorities say around 30,000 of the city's 42,000 people have been vaccinated in recent days.