The Washington State Department of Health has released a statement stating that they are in the midst of a whooping cough epidemic, which will likely reach its highest levels in decades. So far this year there have been 640 cases, compared to 94 cases over the same time period last year. This is a dramatic increase. Whooping cough is a vaccine preventable disease, and so the resurgence of this infection raises questions about the efficacy of the vaccine program – specifically, to what extent is this increase due to vaccine refusal vs waning efficacy of the vaccine itself?
Whooping cough is caused by the Bordetella pertussis bacterium (a Gram-negative, aerobic coccobacillus, for those who are interested), which produce a toxin that paralyzes respiratory cells and causes inflammation. The result begins like an ordinary upper respiratory infection (a common cold) but then develops into a severe cough which can last for weeks. The name of the disease, whooping cough, comes from the sound made by the sudden inhalation after a sustained cough. The disease can be severe at any age, but is especially pernicious in infants, in whom it can cause apnea, or brief pauses in breathing. In infants less than 1 year of age half will need to be hospitalized and 1 in 100 will die.
The pertussis bacterium was first isolated in 1906 by Belgian scientists Jules Bordet and Octave Gengou. In 1939 researchers at the Michigan Department of Public Health demonstrated the efficacy of a vaccine against Bodetella pertussis. The vaccine reduced the incidence of whooping cough from 15.1 to 2.3% and reduced the severity of the illness in those who contracted it. In 1948 the whole cell pertussis vaccine was combined with vaccines for diptheria and tetanus to make the DTP vaccine.