Whooping cough at 50 year high; social mood to blame

CDC: Whooping cough rising at alarming rate in US

Whooping cough has generally been increasing for years, but this year's spike is startling. Health investigators are trying to figure out what's going on, and theories include better detection and reporting of cases, some sort of evolution in the bacteria that cause the illness, or shortcomings in the vaccine.

The vaccine that had been given to young children for decades was replaced in the late 1990s following concerns about rashes, fevers and other side effects. While the new version is considered safer, it is possible it isn't as effective long term, said Dr. Anne Schuchat, who oversees the CDC's immunization and respiratory disease programs.

Some parents in California and other states have rebelled against vaccinations and gotten their children exempted from rules that require them to get their shots to enroll in school. Washington state has one of the highest exemption rates in the nation. But the CDC said that does not appear to be a major factor in the outbreak, since most of the youngsters who got sick had been vaccinated.