Whooping cough is so common that all adults should seriously consider being immunized against the disease, a new study suggests.
The research, published in today's edition of the New England Journal of Medicine, estimates that there are about one million cases of whooping cough in the United States each year, and at least 100,000 in Canada.
Joel Ward, of the Center for Vaccine Research at the University of California, Los Angeles, also found that vaccinating adults would prevent virtually all those cases.
"Pertussis [whooping cough] is one of the least well-controlled illnesses that are preventable by vaccine," he said.
Dr. Ward said the research suggests that adolescents and adults should be vaccinated.
In Canada, whooping cough is part of routine childhood immunizations. Adolescents also get a booster shot. But very few adults get booster shots."From an individual standpoint, there is no question that pertussis vaccination should be offered to all adults," said Scott Halperin, the head of infectious disease at IWK Health Centre in Halifax.
"But in Canada the discussion is: Should we be putting our public health money in a program to vaccinate all adults?"
In other words, public-health officials need to decide whether the adult vaccine should be provided free of charge -- like childhood vaccines -- or whether people should have to pay for the shot themselves. The vaccine costs about $20, plus an additional charge for administration.
Caused by the bacterium Bordetella pertussis, whooping cough is highly infectious and, in young children in particular, it can cause pneumonia, brain damage and death.
Whooping cough gets its name from the high-pitched "whooping" sound made when sufferers are trying to catch their breath between spasms of coughing. In some cases, sufferers cough so hard that it causes a stroke.
It is also a stubborn illness, as the cough can lasts for months in some patients. In the new study, the cough lasts an average of 24 days.
The debate about vaccinating adults has arisen because of soaring rates of the disease. The new research suggests there are about 450 cases per 100,000 population in the United States. (Traditionally, rates have been higher in Canada, in large part because physicians here are more familiar with whooping cough, so it is not often misdiagnosed as bronchitis, as is often the case elsewhere.)
Immunization of children, which began four decades ago, has been a success story. But it turns out the vaccination, or even contracting the disease in childhood, does not confer lifelong protection, and that has led to a resurgence of whooping cough rather than its disappearance.
The waning immunity led to booster shots for adolescents, a measure that is virtually universal in Canada, but still unusual in the United States.
Teenagers, who receive the booster in Grade 9 or 10, might not even realize what they are getting. That is because adolescents already receive a booster of tetanus and diphtheria vaccine, and whooping cough is added to the same shot.
