Doctors believed that whooping cough had been virtually wiped out years ago when a vaccine was developed.

So it is coming as a shock that in California, there have been 2700 cases of whooping cough reported so far this year. This is the worst outbreak in the state in more than 50 years, and is over 8 times the number of cases reported last year. Seven infants who were victims have died.

If a child is not vaccinated, or is not immune, they are susceptible to whooping cough. Most children are vulnerable to the disease until they get their final vaccine for it at 5 years of age.

This whooping cough outbreak raises issues that many experts have been concerned about.  Over the last decade, there has been a large increase in the number of parents who have chosen not to vaccinate their children. There are three schools in California in which more than 80% of the student body is unvaccinated.

It is speculated that parents fear the links between autism and vaccines, and that plays a role in their vaccination choices.