Cases of pertussis, a contagious disease that can be deadly for babies, is on the rise across all age groups in the United States because many adolescents and adults don't realize they need a booster vaccine to stay immunized.
"I think the problem is that for such a long time, people have believed if you were vaccinated as a child or if you had had pertussis, you were protected," said Dr. Tina Tan, professor of pediatrics at Northwestern University's Feinberg School of Medicine and an infectious disease physician at Children's Memorial Hospital. "Because these misconceptions perpetuate for decades, it's very hard to change people's beliefs."
Starting in 2005, the CDC's Advisory Committee on Immunization Practices began recommending the Tdap vaccine, which immunizes against tetanus, diphtheria and pertussis, for adolescents and adults up to age 64. The committee made clear that it is especially important that anyone having contact with children younger than 12 months get vaccinated because infants are not fully immunized against the diseases.
"This is all about protecting the babies," said Dr. Susan Gerber, associate medical director of the Cook County Department of Public Health. "That's the group of the population you want to protect because the babies can become quite ill."
Only 56 percent of adolescents have Tdap coverage and in adults, it's less than 6 percent, according to a Centers for Disease Control and Prevention report released in January. In 2009, there were 16,858 documented pertussis cases nationwide and 12 subsequent infant deaths.
It has long been recommended that the general population receive tetanus-diphtheria booster shots every 10 years. But Tdap is the first vaccine offered to anyone other than children for immunization against pertussis, Gerber said.
Tdap is necessary because it's now apparent that childhood vaccines for pertussis wane by the teen years, according to the National Foundation for Infectious Diseases. Pertussis, also called whooping cough, can cause coughing spells so severe they make it hard to breathe, sleep or eat.
Some people might not even realize they have the disease or think it's a common cold, but sufferers can wind up with cracked ribs or pneumonia, experts said.
The disease is easily spread by coughing, sneezing and close contact. Studies show that it's primarily parents who infect their children, Tan said. Ideally, the Tdap vaccine would be given to women before they get pregnant, but few gynecologists give the vaccine, and most women of childbearing age don't know to ask for it.
In an effort to get more people vaccinated, the Advisory Committee on Immunization Practices in October expanded the categories of people it recommends receive Tdap. It can be given to adults 65 and older as well as children ages 7 through 10 who weren't fully vaccinated at a younger age. And people no longer have to wait a specified amount of time — previously five years — after getting a tetanus-diphtheria shot to get a Tdap vaccine.
"Eliminating that (time) interval will get more people vaccinated," Gerber said.
One catalyst behind the vaccination push was the California outbreak of pertussis in 2010 when 9,477 cases, including 10 infant deaths, were reported, according to the CDC. That is the largest number reported there in 65 years.
It is difficult to get every adult and adolescent immunized against pertussis, which is the recommendation of the CDC's advisory committee, Tan said. So priority has been given to specific groups — including postpartum women, anyone in contact with a child younger than 12 months and health care providers who have direct contact with patients.
Also, anyone planning a trip should consider a Tdap booster, Tan said. "Pertussis is endemic worldwide."
And those requiring a tetanus shot because of a wound should go ahead and get the Tdap booster, she said.
Side effects of Tdap are redness, swelling and soreness at the injection site.
"There are not serious risks," Gerber said. "This is a safe vaccine."
For now, it's recommended that adolescents and adults, no matter their age, receive only one dose of Tdap in their life. If 10 years pass after getting the vaccine and officials have not recommended a second dose, people should go back to getting the tetanus-diphtheria booster as usual, Tan said, adding that she expects the recommendation to become Tdap every 10 years.Copyright © 2014, Los Angeles Times