Pertussis is one of the leading causes of unnecessary infant and child deaths worldwide. The deaths could largely be prevented with a vaccine. Most of the cases of pertussis occur in developing countries, but the U.S. has seen an increase in recent years.
Pertussis often starts with cold-like symptoms, but Lara Misegades at the U.S. Centers for Disease Control says that's where the similarities end. She led a study that was published in the Journal of the American Medical Association.
“Pertussis is a very contagious respiratory disease, and it’s also known as whooping cough. It’s caused by a bacteria and it can cause violent coughing fits that last for a very long time, up to 10 weeks or more," she said.
Colds are caused by viruses. Like a cold, pertussis can affect anyone but can be life-threatening for infants, young children and the elderly.
Globally, up to 50 million people get pertussis each year and it causes 300,000 deaths. Ninety percent of the cases are in developing countries. A vaccine can prevent the disease.
The vaccine is given in a series of four shots during infancy and another just before a child starts school. Because of the increase in cases, the researchers studied vaccine histories to see if those who got the disease had completed the five dose series.
"Children with pertussis were less likely to have received the childhood pertussis vaccine series compared to children who did not have pertussis," said Misegades.
The researchers also found that protection from immunization declines over time.
Dr. Gregory Poland at the Mayo Clinic in Minnesota says the vaccine is highly effective at first.
"In year one, after getting the vaccine, the efficacy is nearly 100 percent, which is why I say it is an excellent short-term vaccine. By year five, you’re down to an efficacy of about 30 percent," he said.
Dr. Poland says pertussis is mistakenly called a childhood disease. It's really a disease that adults and teenagers give to children.
Doctors recommend that pregnant women get a booster vaccine so they don't get sick and so their newborns have some protection. Doctors also recommend that adults who spend a lot of time with young children get periodic boosters.
"It really is an all-round education effort to get people to realize that anyone is susceptible to pertussis, everyone needs to get a vaccine or booster against pertussis, and anyone who has a nagging, ongoing cough that lasts and lasts and lasts, ought to see their physician with the thought of pertussis," he said.
The goal is to develop a better vaccine, but meantime people can take basic steps, such as washing hands often and getting vaccinated.