BURLINGTON (AP) - Vermont health officials are discussing the state's response to a whooping cough outbreak that's affected at least 500 people this year.

Health department officials say the number is 10 times the amount reported by the end of 2011.

More than 20 babies younger than a year have been confirmed to have the disease.

Health officials are discussing the outbreak at a news conference at 1:30 p.m. Thursday at the Vermont Department of Health on Cherry Street.