WASHINGTON, D.C. The recent increase in reported cases of pertussis prompted experts to encourage parents and physicians to vaccinate children with acellular pertussis vaccines.
--- X-ray of a child with pertussis.
A total of 7,138 pertussis cases were reported nationwide during 1996; the average number for pertussis cases per year is approximately 3,000. The CDC reported 682 cases during the first quarter of 1997, compared with 372 for the first quarter of 1996; an 83% increase in reported cases.
The United States is currently in a peak phase of pertussis incidence, according to the Centers for Disease Control and Prevention (CDC). To increase awareness of these cases, Every Child By Two, a government program that promotes the timely immunization of children from birth to age 2, convened a panel of experts from the fields of nursing, public health, pediatrics and vaccine research.
"The key message is that it is important more important than ever for parents to ensure that their infants and children receive full age-appropriate immunizations, especially against pertussis," said Mary Kopp, MN, RN. "Vaccines are the best way for parents to protect their children against this disabling disease."
Pertussis increases and decreases in cycles, and experts have not identified the specific reason for the current peak. Several factors have been implicated including: increased awareness among physicians, adult transmission to unvaccinated or incompletely vaccinated infants and young children, low immunization rates in some affected areas and waning vaccine immunity.
The increasing cases and outbreaks of pertussis in several states are a reminder of a disease that many thought was gone. Pertussis claimed the lives of 9,000 people in 1923. In the 1930s, there were approximately 250,000 cases a year of pertussis, with 260,000 occurring in 1934.
January to April
"Pertussis is one of the oldest diseases we know," said Ed Thompson, MD, MPH, Mississippi State Health Officer. "It received its name in 1670."
This long and protracted illness can last from six to 10 weeks in a typical unvaccinated person, said Thompson. The cyclic outbreaks remind us that Bordetella pertussis is everywhere; it continues to be seen in the nose and throat of otherwise healthy people.
"It is a bacteria that is all around us and we are unlikely to eliminate it in the foreseeable future," said Thompson, representative of the Association of State and Territorial Health Officers. "The only protection is to immunize our children completely against it."
The first vaccine was introduced in the 1930s. By the mid-1970s, pertussis cases fell to a low of about 1,000. Smaller peaks began to appear in the late '80s, topping off at a few thousand.
"We've been victims of our own success in controlling this disease because now few parents and physicians have seen or learned to fear pertussis," he said. "The vaccine brought the disease to low levels, but it's occurring more frequently now than it did in the last five or six years. That's a wake-up call."
The available vaccines are good, but not perfect. The best chance to protect a child is to make sure that child is fully immunized. Three doses of vaccine gives a child about a 64% chance of being protected. At four doses, the protection level rises to about 80%.
"The way to control outbreaks is not to go after the outbreak, but to stop it beforehand. The way to do that is to immunize," Thompson said. "We have to give all of our children all of their shots pertussis and otherwise as soon as they can get them."
Physicians should tell all parents about the new harmonized schedule, because parents often forget that fourth dose, said Barbara Watson, MD, medical immunization specialist, Philadelphia Department of Health.
"In Philadelphia during the 1993 outbreak, only 30% of the children had received the appropriate fourth dose," said Watson, who is also director of the Vaccine Evaluation Unit at Albert Einstein Medical Center, Philadelphia. "Half the children who got pertussis in Philadelphia last year were younger than age 1 and were hospitalized. Most of those children had not had their shots on time."
Fifty percent of infants who contract the disease are hospitalized. Benefits of pertussis vaccinations far outweigh the risks. Today's acellular vaccines make immunization easier, Kopp said. Fewer reactions and less fever and crying associated with acellular vaccines should help alleviate some parents' concerns.
"When parents know they are going to have less anxiety during this immunization process and that their children are going to have fewer reactions, then everyone is going to worry a lot less about receiving these immunizations, and that's important," said Ronald J. Saldarini, PhD, president of Wyeth-Lederle Vaccines and Pediatrics.
Every Child By Two is the Carter/ Bumpers Campaign for Early Immunization founded in 1990 by former first lady Rosalynn Carter and Betty Bumpers, wife of Arkansas senator Dale Bumpers.
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