Health officials are urging pertussis vaccines in young children and boosters in adolescents, as the number of pertussis cases have hit around 18,000 and pertussis has contributed to the deaths of nine infants this year alone.
Anne Schuchat, MD, Assistant Surgeon General of the United States Public Health Service and Director of the National Center for Immunization and Respiratory Diseases at the CDC, said during a press conference that a report published in this week’s Morbidity and Mortality Weekly Report demonstrates just one state’s experience with pertussis, and similar occurrences are being noted across the country. She said that pertussis rates are the highest this year since 1959.
The MMWR report highlights Washington state, where there have been more than 2,500 cases reported there between January and June 2012 – more than triple the rate reported at the same time last year — with most cases being reported among the adolescents. Schuchat said that waning immunity of the pertussis vaccine is a likely contributor. She added that diphtheria toxoid and acellular pertussis vaccine (Tdap) efficacy is the “centerpiece” of what health officials are investigating in Washington, since recent estimates claim the vaccine is 66% to 72% effective.
“But those measurements were carried out in children who had received their baby shots with the old whole-cell vaccine,” Schuchat said. “Whether the duration of protection or the short-term effectiveness is different in Tdap among teens who got acellular protection as babies, we don't know yet.”
Schuchat noted that pertussis epidemics occur in 3- to 5-year periods, but this is the highest wave seen in decades.
“In this current wave nationally, we're seeing the highest rates of pertussis in infants younger than 1 year of age. About half of these cases are babies under 3 months of age. That’s because those very young babies are too young to be protected by vaccines that they start getting at 2 months of age,” Schuchat said. “Their protection instead depends on the immunity of the people around them, especially pregnant women, their mothers. That is why we strongly urge pregnant women and all who will be around babies to be vaccinated.”
She added that unvaccinated babies are at an eightfold higher risk than vaccinated babies for contracting pertussis.