AUSTIN, Texas - The Texas Department of State Health Services is urging people to make sure they are immunized against whooping cough after six deaths and more than 1,000 cases so far this year.

The health department said Thursday the six deaths are the most for a single year since 2005.

The deaths have included five infants under 2-months-old, the age when the first vaccination is recommended. The health department says that demonstrates how important it is for parents and others around newborns to get the recommended doses.

The sixth death was an unvaccinated older child with underlying medical conditions.

There were 961 total Texas cases of pertussis last year, down from a peak of 3,358 in 2009.

Whooping cough, or pertussis, is a contagious bacterial illness that can lead to severe coughing.

For more on information on Pertussis, including symptoms and current trends, you can access the Texas Department of State Health Services website as listed below.