Texas Department of State Health Services spokeswoman Carrie Williams said Thursday the agency was alerted about the allegations in late October. Charles Fischer was placed on emergency leave the next morning and fired Monday.
A phone message left at Fischer's home in Austin on Thursday was not immediately returned. The Austin American-Statesman first reported his firing.
Austin police spokesman Veneza Aguinaga said an investigation surrounding Fischer has begun but that no charges have been filed.
State officials said there are several past allegations of sexual abuse involving Fischer dating back "several years" but that none were confirmed until now.