California has worst whooping cough season since 1950

Through November 9 this year, California has seen its worst season of whooping cough, or pertussis, since 1950.

With another seven weeks left in 2010, it is doubtful that the 1947 pertussis record of 9,394 cases will be broken, but with 6,631 cases, the 1950 record has been surpassed, according to

The current pertussis rate in the state is 16.9 per 100,000 people. Of the last 200 reported cases, 63 percent are confirmed, 19 percent are probable and 19 percent are suspect, reports.

Experts have said that incidents of whooping cough have been rising over the last 25 years because of the falling number of people, including children and babies, getting routine vaccinations.

This year, there have been 10 deaths attributed to pertussis in California - all of them infants. Of the 10 fatalities, nine of the infants had not been vaccinated, and the other was a 28-week premature baby who had received the initial DTaP vaccine dose 15 days prior to developing symptoms - too early for immunization to properly have been formed.

Nine of the victims were of Hispanic origin and nine were two months old or less when the diseases symptoms started, reports. California health authorities have said that most of the babies that have been affected are less than three months old.

Fifty-eight percent of all hospitalized patients were less than three months old and 75 percent were less than six months old. A significant proportion have been Hispanic in origin.

According to the Centers for Disease Control, 25,616 cases of whooping cough were reported in 2005. An epidemic was declared in California earlier this year.