Whooping cough has been declared an epidemic in the heartland of the American anti-vaccine movement.

California's whooping cough rates continue to rise, as the Centers for Disease Control keep urging people to get vaccinated.

California has seen 3,458 reported cases of pertussis (whooping cough) this year, and about 800 cases in just the last two weeks.

“We urge all pregnant women to get vaccinated,” Dr. Ron Chapman, director of the California Department of Public Health told the L.A. Times.

“We also urge parents to vaccinate infants as soon as possible.”

Newborns and infants have the greatest risk of death from pertussis, which has claimed the lives of two babies in California so far this year.

But babies cannot be immunised until 6 weeks of age, so public health officials are urging pregnant mothers to get vaccinated on their behalf.

Authorities say that from the start of 2014 to April, there have been 4,838 cases of whooping cough in the US - up 24 per cent over the same period in 2013.

According to reports, California has some of the lowest vaccination rates along with the highest rates of pertussis in the nation.

The anti-vaccination movement is strong in the state, frequently whipped-up by the impassioned but scientifically-baseless fears of some 'celebrity' mothers. 

This page describes the necessity of large-scale vaccination for population immunity, the rigorous nature of the medical trial process, and the effectiveness of proper vaccine regimes.