[The father of Joseph Fielding, 4, says Joseph is lucky to be alive after a bout with whooping cough when he was 6 weeks old. Joseph had not been vaccinated yet. Daniel Wallace | Times]

Do you want to know more about vaccine safety? A Times report looks at the debate over vaccines and autism. Dr. Gregory Poland, one of the nation's top vaccine scientists, has agreed to answer questions from St. Petersburg Times readers.

Poland, director of the Mayo Clinic Vaccine Research Group , helps set national vaccine policy as a liaison member of the federal Advisory Committee on Immunization Practices. If you have a question, post it here by noon Monday. Poland will provide answers to select questions on Tuesday.

*** Dr. Gregory Poland's responses are in.

Complete coverage:

Part one: Debate rages over need for vaccines

Part two: Shots fired over flawed vaccine

Some favor vaccine delays

Interactive: Compare the data