In Pennsylvania, the State Health Department reports nearly 1400 confirmed cases and 250 probable cases, this year. That compares to 742 both confirmed and probable cases last year.
Children are better protected after receiving a 5-dose vaccine series. A new study examined the relationship between whooping cough and time that's elapsed since a child received the fifth dose of the vaccination series
The pertussis vaccine is recommended for all children beginning at two months of age, in a series of 5 shots. The fifth and final shot is recommended between the ages of 4 and 6.
Dr. Lara Misegades from the Centers for Disease Control and Prevention and co-authors examined the relationship between pertussis and receipt of five doses of D-Tap by time since the last dose of the newer vaccine. This study was conducted after California, in 2010, experienced its largest pertussis outbreak in more than 60 years.
Researchers reviewed vaccine histories for children four to 10 years old in 15 counties comparing those who had pertussis and those who did not. They looked specifically at whether a child had completed the five dose series or was unvaccinated.
According to Dr. Misegades, "children with pertussis were less likely to have received the childhood pertussis vaccine series compared to children who did not have pertussis." The study appears in JAMA, Journal of the American Medical Association.
"Within one year after having received the fifth dose of vaccine about 98 percent of children were protected against pertussis but when we moved out to five years after having received the fifth dose about 70 percent of children were protected. Protection faded over time," Dr. Misegades says.
Researchers say a booster shot is also recommended starting at age 11. Pregnant women and anyone coming into contact with infants who are not fully vaccinated are also encouraged to get the booster. As with any vaccine program researchers say it's important to continually evaluate how well it's working.