After releasing the Morbidity and Mortality Weekly Report (MMWR) on the whooping cough epidemic that’s occurring in Washington state, the Centers for Disease Control said as of Thursday, "nationwide, nearly 18,000 cases have been reported to CDC."
The figures shared by Dr. Anne Schuchat during a CDC telebriefing held on July 19, are "more than twice as many as we had at the same time last year," said the director for the National Center for Immunization and Respiratory Diseases at CDC. That's more "than we had in each of the past five years," the doctor said, meaning the nation "may be on track for record high pertussis rates this year."
Whooping cough is a highly contagious respiratory tract infection that presents initially like an average cold. As it becomes more serious, people with the disease cough violently and rapidly until all the air has been exhaled from their lungs. When they inhale, they do so with a loud "whooping" sound.
The situation is so dire at present added Schuchat, we "may need to go back to 1959 to find a year with as many cases reported by this time so far." Whooping cough also called Pertussis, occurs in waves with peaks that occur around every three-to-five years explained the director, and "while it is a cyclical season, a gradual and sustained increase in pertussis has been seen in the U.S. after we reached historic low levels in the 1970s."
Typically pertussis affects young babies the most, nine babies have died from whooping cough just this year. But of concern Schuchat said, is "we’re also seeing high rates in older children as well." High rates are also being seen among children 10 years of age she added, at an age when immunity can wane from earlier vaccinations.
Dr. Mary Selecky, the Secretary of the Washington state health department, said that the "whooping cough situation in Washington state has been incredibly challenging. We're seeing the largest number of cases in our state since the early 1940s," she added. By the end of last week, 3,000 cases had be reported to the health department, up from the 200 reported at the same time last year. The astonishing figures have skyrocketed from the 640 cases reported April 3rd when the state declared the pertussis epidemic.
Researchers also appear concerned about unusual things occurring epidemiologically with the illness that don't jibe with past trends or pertussis cycles. Scuchat said:
If we look at the teenage group, what we see is that disease rates start to come up after late childhood. You know with the higher rate in 10-year-olds. Then we actually have a decrease in the 11 and 12 year olds and higher rate in 13 and 14 year olds. There is a lot going on in the age group that is a bit different than what we saw in the last wave, several years ago.
Although TDaP vaccination is still the best recommended defense against whooping cough, in Washington state it has been measured to be about 60 percent to 70 percent effective, the director said, meaning that its effectiveness "is the center piece of what we would like to be investigating," she added.
But even parents who vaccinate their children according to the recommended schedule can provide risks if they themselves are not vaccinated. A baby's protection, Schuchat said, "depends on the immunity of the people around them, especially pregnant women, their mothers. That is why we strongly urge pregnant women and all who will be around babies to be vaccinated. Infants often get pertussis from a family member or household member."
The CDC reports that in a 2010 National Household Interview Survey of 19-to-64 year-olds, "only 8.2 percent of adults have gotten TDaP." Other causes for the elevation in cases include several factors, Schuchat said, "including immunity provided by the pertussis vaccine which can wane over time." But the director added, "increased reporting and increased diagnosis" could also mean that health departments and the CDC receive better information today to compare with 1970s statistics.
Information on recommended vaccines for all ages is available at CDC.gov.