A second booster shot against the returning menace of whooping cough won government approval yesterday -- this one for adults as well as teenagers.

The cough so strong it can break a rib was once thought to be history because of vaccination of babies and toddlers. But protection from those early-in-life shots wears off, and outbreaks among adolescents and adults have increased dramatically. While older patients usually recover, whooping cough can cause weeks of misery. The illness can also spread easily to not-yet-vaccinated infants, who are at risk of dying from the bacterial infection.

A month ago, the Food and Drug Administration approved the first booster shot, GlaxoSmithKline's Boostrix, for 10- to 18-year-olds.

Yesterday rival Sanofi-Aventis won FDA approval for its whooping cough booster, Adacel, for people ages 11 to 64.

Both combine protection against whooping cough, also called pertussis, in the same shot with a standard booster against tetanus and diphtheria. Children are supposed to get that so-called Td booster sometime between the ages of 11 and 18, and adults are encouraged to get a tetanus booster every 10 years.

The new combination shot can now be sold, but doctors usually wait to administer new inoculations until they are formally added to the nation's official vaccination schedule -- a step that also ensures insurance coverage. Later this month, an advisory committee of the Centers for Disease Control and Prevention is expected to add the adolescent booster to that list.