Save yourself 100 days of coughing
Whooping cough can be fatal to babies, writes MUIRIS HOUSTON
THE MEDIEVAL-sounding “100-day cough” is back. Despite the long-time availability of pertussis vaccine, whooping cough is on the march again. And not just in Ireland, but also with outbreaks in Australia, Canada, the US and Europe.
A GP in Melbourne says, “We’ve had an epidemic of pertussis here in the last 18 months, just waning now. Adults tend to present with a cough that occurs in spasms often lasting minutes and, once passed, then no coughing for minutes or even hours. Spasms may be associated with retching, rarely vomiting. We’ve also proven it in adults whose only symptom was protracted persistent non-productive cough.”
Whooping cough refers to the classic “whoop” sound which occurs during inspiration. It is heard most commonly in babies with the disease. In adults, the more typical picture is one of an initial “normal” cough – like you get with a regular cold – which becomes paroxysmal, but without the whooping sound.
The coughing is severe and prolonged; patients will often tell you they cough until they are blue in the face.
Up to July 15th this year, the number of cases of pertussis reported to the Health Protection Surveillance Centre (HPSC) has tripled compared with the same period last year. Some 244 cases of the infectious disease have been reported, continuing a trend that started in 2011. “The age group most affected are young infants aged less than six months [76 cases], with almost two-thirds of these cases being under three months. Many were either unvaccinated or incompletely vaccinated,” the HPSC said in a recent update.
Of course, babies under two months cannot be vaccinated and are reliant on older victims of whooping cough being diagnosed and treated early.
Once diagnosed, those who have it must stay away from young children and infants until they have been adequately treated. The treatment of people who are close contacts of pertussis cases is also an important part of prevention.
Pertussis can be fatal, especially in babies less than a year old. An indication of its potential lethality is that 71 of the 244 cases identified so far this year in Ireland have required hospitalisation; some three-quarters of these patients were aged less than six months, an age group that represents nearly 90 per cent of all pertussis-related deaths. Reasons for admission include pneumonia and brain damage.
Whooping cough is caused by infection with the bacteria Bordatella pertussis. It is spread by coughing and sneezing, and is highly infectious. The bug is sensitive to the antibiotic erythromycin, but treatment within seven days of the onset of symptoms is required if a prolonged cough is to be avoided.
In the 1990s and 2000s, findings from various pertussis surveillance systems demonstrated a change in the age profile of pertussis cases in countries with high vaccine coverage rates in young children. There has been a definite shift in the age group affected, with increasing pertussis incidence among adolescents and adults.
This raises questions about how long vaccine-induced immunity lasts. Best estimates for duration of immunity to whooping cough are between seven and 20 years after infection, and between four and 12 years after vaccination. But the duration of protection after the first three doses remains unclear; there have been calls for the introduction of a pertussis booster vaccine in the second year of life.
What is the current pertussis vaccine policy in the Republic? It starts with the “6-in-1” vaccine at two, four and six months, administered by family doctors. A fourth dose is recommended at four-five years, when a child starts school. A further booster using Tdap, which contains low-dose acellular pertussis vaccine, was introduced to the school immunisation programme in the 2011/2012 academic year on a phased basis for first-year students in second-level schools. It is planned to extend this to all areas from next September.
So the message is clear: get vaccinated. One hundred days of severe coughing is bad enough if you are an adult; but for a baby, whooping cough can be a killer disease.