On a positive note, "the findings have raised the attention of the manufacturers," Klein said of the study she led.
She hoped the results would encourage the development of more effective alternatives.
"Prevention of future outbreaks will be best achieved by developing new pertussis-containing vaccines that provide long-lasting immunity," the authors concluded in the study.
Aside from potential allergic reactions, new and frequent boosters should be evaluated for length of protection, cost-effectiveness and feasibility of introduction into the childhood care schedule, said Dr. William Schaffner, chairman of preventive medicine at Vanderbilt University Medical Center in Nashville, Tenn.
The Kaiser Permanente study "provides strong confirmatory evidence that the current vaccine's effectiveness declines over time," Schaffner said. "The magnitude of the decline is striking and will accelerate the deliberations concerning more-frequent booster doses."
Experts cautioned that the study does not suggest that parents stop vaccinating their children.
"The question it raises is whether we should give vaccine more frequently -- not ever or less frequently," said Dr. Gregory Poland, director of the Mayo Vaccine Research Group in Rochester, Minn.
Those who developed whooping cough after vaccination had mild or moderate illness, not the more-commonly-occurring severe disease that can strike in the absence of vaccination.
"Hence," said Poland, who studies vaccine response in adults and children, "even in this study, the vaccine offered benefit."