Whooping cough on the rise in California

By Dr. Ananya Mandal, MDSep 19 2010

Whooping cough is on the rise in California and the number infected has reached a 55-year high, including nine infant deaths, eight of them Hispanics. There have been more than 4,000 confirmed, probable or suspected cases this year, the most reported since 1955.

The Centers for Disease Control (CDC) released the results of their 2009 National Immunization Survey (NIS) reports. It says that in New York State infants and toddlers have been immunized according to schedule for whooping cough at an 84% rate, with a range of 80% to 88%. Teens and adults have received the booster immunization at a rate of 69.2% with a range of 64.3% to 73.7%. New York City has higher rates than the rest of New York State. Twenty seven states however have lower immunization rates for whooping cough also known as pertussis, than the national average in children under age 3. As per recommendations at least four doses of vaccine by 3 is needed. Nationally, the rate complying with that schedule is 83.9% with a range from 82.9% to 84.9% the report said. Recommendations suggest children receive 5 doses of the DTaP vaccine (against Diphtheria, Pertussis and Tetanus) before age 6. They also suggest that they receive a dose of TdaP (against Pertussis and Tetanus) at age 11 or 12. Depending upon the patient's immunization history, the CDC suggests an adult may need one dose of TdaP.

27 states that have low immunization rates for infants and toddlers are twelve of the twenty that currently allow parents to refuse immunizations based on a “strong personal belief”. California, Texas and Ohio all allow such an exemption and these three are the only states reporting over 1,000 cases of whooping cough in 2010 through September 11. 70% of the cases have been reported from these areas in the CDC's Week 36 MMWR report when an undercount from California of 2,603 cases is included. The twelve states with a personal belief exemption and vaccination rates below average make up 59% of the reported cases.

Infant and toddler vaccination rate in California in 2009 was 83.4%, with a possible range of 78.7% to 88.1%. Vaccine coverage for teens and adults in California was much worse. The coverage for the booster suggested to prevent whooping cough was reported in the NIS survey as 53.1% with a range of 46.7% to 59.5%.

Australia's foreign affairs department on Thursday warned travelers to the United States to watch out for the outbreak, which has also been reported in a number of other US states. The department maintained its overall advice at “exercise caution,” the second of a five-level warning system.