In 2010, there were more than 21,000 cases of whooping cough nationwide, with the worst outbreak in California.

Members of the Advisory Committee on Immunization Practices advise pregnant women who previously were not vaccinated to get one, ParentDish.com reports.

Children get whooping cough vaccine in a series of shots beginning at 2 months, but researchers have found getting a shot during pregnancy enables women to pass some immunity to their children.

The vaccine, which does not use live bacteria, would be given to pregnant women in the third trimester or late second trimester.