As an infectious disease clinician and also an individual fond of the dramatic arts, I can't help but use a theater metaphor to describe the cyclical nature of our specialty. As swine flu takes a bow and is swept backstage to join SARS, bird flu and the other actors of times gone by, a new performer seems to be taking the spotlight. Pertussis (stage name: Whooping Cough) has been drawing quite a bit of attention lately, especially in my home state of California. Given the fear and anxiety that seems to be surrounding this new production, it is worthwhile to try and demystify things a little.
Whooping cough is a very contagious disease caused by the bacteria Bordetella pertussis. It is spread from person to person, usually by sneezing or coughing, often at distances of five feet or less. Once inhaled, it attaches to the small hairs inside your nose and then replicates causing inflammation in your upper airways. It is not a new disease and medical reports of this infection date back to the 16th century. Its name, Pertussis, comes from Latin roots meaning "intense cough."
Pertussis most commonly affects infants and young children, although adults may become infected as well. The classic presentation occurs in three stages. The first stage lasts one to two weeks. At this time people are the most infectious and may have symptoms very similar to the common cold, such as runny nose, low fever and mild cough. The second stage is where the disease's name comes from. In this stage, people may experience severe coughing fits. Sometimes the cough is so severe, it is followed by vomiting. After a coughing spell, the patient may classically gasp for air causing a high pitched "whooping" sound. This phase may last several weeks, usually two to six. The last phase is the recovery phase where the cough gradually subsides over approximately two weeks.
It is important to note that often the disease presents itself differently in different age groups. Infants may have short periods between coughing spells where they stop breathing called "apnea." Adults or children who have already been vaccinated often present with less severe symptoms making it harder to diagnose. Therefore it is something to think about in anyone, vaccinated or not, who has had a persistent cough for two weeks or more. Diagnosis occurs after a conversation and exam by your doctor. A sampling of secretions from the back of the nose and throat can also assist in diagnosis. Once a diagnosis is made, it is a treatable infection and several antibiotics, such as Azithromycin, are effective.
The important thing to remember is that infants, especially those less than one year of age, are the most severely affected. More than half of them will require hospitalization. They are the ones we are trying to protect the most with vaccination programs.
Outbreaks of Pertussis are not a new thing, and usually occur cyclically every three to five years. The last peak was in 2005 when about 25,000 cases were reported nationally. We are having another outbreak currently in California with more than 6,000 cases diagnosed so far this year, including 10 infant deaths. This is the largest number of new cases in 50 years. Reasons for this increase may include decreased use of the vaccine, fading of immunity in adolescents and adults previously vaccinated, and increased awareness of the disease leading to more reporting.
Rather than panicking, the important thing to remember is that education and understanding of the disease is the best remedy to fighting it, and vaccination is key. Right now the Centers for Disease Control recommends all children six weeks to six years be vaccinated with the routine DTap (for diphtheria, tetanus, and pertussis). Adolescents and adults who have previously been vaccinated should receive one booster dose of Tdap (it protects against the same diseases as DTap, but the concentrations in the booster vaccine are different). Populations who should be especially vigilant about getting the booster are women of childbearing age and those who will have close contact with pregnant women or infants.
By next year, the Pertussis production will likely fade out of the limelight to be replaced by another infectious starlet. Likely Pertussis will return for a reprise in a few years. In the meantime, we'll be in line at the vaccine window.