Young people who have been vaccinated against pertussis but still contracted the disease recovered more rapidly and suffered less severe symptoms than other pertussis patients, according to a study led by a University of Washington School of Public Health graduate student.

Pertussis, also known as whooping cough, has been on the rise since the 1980s despite high rates of vaccination. Researchers wanted to study the course of the illness in people who succumbed to the illness despite having been previously vaccinated, said lead author Russell Barlow, MPH, a PhD student in the departments of global health and immunology. Researchers analyzed 633 pertussis cases in the Portland (OR) metropolitan area among children six weeks to 18 years of age. The cases occurred between 2010 and 2012.

Barlow and his colleagues found that those who had been vaccinated but still fell ill were five times less likely to be hospitalized and 2.5 times less likely to develop severe illness compared to unvaccinated persons. "These results are important because they highlight that while the current vaccines may not perfectly protect people from becoming infected, they still appear to protect persons from life threatening disease – especially among infants – and help them to recover more rapidly," Barlow said.

The research was published in the journal Clinical Infectious Diseases and was carried out with the Multnomah County Health Department and the Oregon Health Authority with funding from the US Centers for Disease Control and Prevention.