More than just a little cough
A dry, tickly cough, a runny nose and a slight fever - the first symptoms of whooping cough are reminiscent of a cold. Children are tucked up in bed with tea, tissues and a good story. Adults usually ignore the signs of illness and drag themselves to the office feeling groggy. Until the symptoms - for young and old - get worse and the coughing attacks become so severe that you vomit. At best, this is simply unpleasant.
However, whooping cough can quickly become life-threatening for babies and people with a weak immune system or a serious underlying illness: They suffer from respiratory failure, and the lungs can become inflamed or permanently damaged. "The signs of the disease are often atypical at the beginning, i.e. they cannot be clearly assigned to whooping cough, so the diagnosis is often not made at the time.
The number of cases is rising again, mainly due to vaccination fatigue.
At the same time, the patients are already highly infectious at this point," says Cornelia Feiterna-Sperling from the Department of Paediatrics with a focus on pneumology and immunology at Charité Universitätsmedizin Berlin. This means that patients who cope well with whooping cough themselves and misinterpret it as a persistent cold or bronchitis become a danger to others. This is because sufferers are contagious for at least three weeks and infect an average of 17 other people during this time. In addition, whooping cough often takes an atypical course, meaning that the familiar stages do not occur in this form at all.
Whooping cough is a protracted disease that usually goes through three stages. The tricky thing about the disease is that there are often atypical courses in infants and children as well as in adolescents and adults.
- Stadium catarrhale
Etwa sieben bis vierzehn Tage nach der Infektion bekommt der Erkrankte für ein bis zwei Wochen grippeähnliche Symptome: leichtes Fieber, Schnupfen, einen trockenen Reizhusten. Jetzt ist der Patient am ansteckendsten. - Stadium convulsivum
Zwei bis sechs Wochen lang treten die charakteristischen krampfartigen Hustenanfälle auf, an deren Ende der Betroffene meist laut keuchend einatmet. Er würgt Schleim hoch oder erbricht sich. Die Hustenattacken sind häufig und werden vor allem nachts oder bei körperlicher Anstrengung schlimmer. - Stadium decrementi
In dieser mindestens drei bis sechs Wochen dauernden Phase werden die Hustenattacken nach und nach weniger häufig und schliesslich auch weniger schwer. Bekommt der Patient keine Antibiotika, kann sich das dritte Stadium auch sechs bis zehn Wochen hinziehen.
In infants under six months of age, the second stage usually does not manifest itself with the characteristic coughing fits, but with apnoea. «Infants in the first year of life also have an increased risk of serious complications such as apnoea, pneumonia or seizures,» says Feiterna-Sperling.
Adolescents and adults are often not diagnosed with whooping cough because their only symptom is a dry cough. The problem is that the pathogen can still be detected in their blood, meaning they can infect others.
The treatment is lengthy
Whooping cough is one of the most common infectious diseases of the respiratory tract worldwide. Those affected cough for several weeks or even months. This is why the disease is popularly known as the 100-day cough. The pathogen that causes whooping cough is called Bordetella pertussis. This rod-shaped bacterium produces toxins that damage the mucous membranes of the respiratory tract. This in turn causes the symptoms. At the same time, Bordetella pertussis feels very comfortable in these mucous membranes and multiplies there.
The pathogen Bordetella parapertussis can also cause whooping cough. However, less than 20 per cent of people infected with this bacterium contract whooping cough, with the majority developing simple acute bronchitis or not noticing the infection at all. Whooping cough, says Ulrich Heininger, is complicated on many levels. The professor is a senior physician in Paediatric Infectiology and Vaccinology at the University Children's Hospital Basel and has completed his post-doctoral thesis on pertussis - the medical name for whooping cough.
A single vaccination is recommended for adults. Experts believe that this is not enough.
«The disease is very protracted. The symptoms initially resemble those of a cold, which makes diagnosis difficult. And treatment must be started as early as possible - when you don't actually suspect that it could be whooping cough,» says Heininger. Nevertheless, there are vaccines that are effective and well tolerated. These so-called acellular whooping cough vaccines achieve an effectiveness rate of 85 per cent.
This means that for every six people vaccinated, one remains unprotected. In order to completely eradicate a pathogen that only occurs in humans, the vaccine would have to be 95 per cent effective and the vaccination coverage rate would have to be 95 per cent.
Back in the 1940s, scientists developed a vaccine against whooping cough that was more effective than today's variants. However, this so-called whole-body vaccine was significantly less well tolerated: many children developed fever, swelling and pain after the vaccination, and in the 1990s it was even suspected that the pertussis vaccine was the cause of severe brain damage or death in young children.
The pathogen continues to circulate
«This has been intensively investigated. Today we know that this is not the case, but all this was reason enough to develop new vaccines,» says Heininger. Today, children - and adults in many countries - are immunised with acellular vaccines throughout Europe, with the exception of Poland, and doctors have traded better tolerability for slightly poorer efficacy. As a result, the pathogen continues to circulate in the population and outbreaks occur here and there. According to the Federal Office of Public Health, there was an epidemic in Switzerland in 1994/95 with a total of around 46,000 cases.
Neither a previous illness nor a vaccination against whooping cough offers long-term protection against the disease.
After that, there was a steady decline in the number of cases, but an upward trend has been observed again since 2010. In the period from 2010 to 2014, an average of 8,700 cases were reported annually. The proportion of adolescents and adults among patients has tended to rise in recent years.
Around 30 children are currently hospitalised in Switzerland every year due to whooping cough, most of them infants. Four pertussis-related deaths have been reported in the last 15 years. «This is not a national emergency, but the tricky thing about whooping cough is that there can be a major outbreak at any time and then suddenly 15 babies die from it in one year,» says Heininger.
No longer just a childhood disease
A lot has happened in the last fifty years: the number of cases of the disease has fallen considerably. The fact that it is now rising again, especially among adolescents and adults, is due to vaccination fatigue. While around 95 per cent of infants are vaccinated, experts estimate that the refresher rate for adults is less than eight per cent.
How do I get infected?
Whooping cough is highly contagious; almost every contact between a sick person and a healthy person leads to infection. If the healthy person is protected by vaccination, they can probably still pass on the bacteria to others and infect them - the exact pathways are still being researched by scientists. Whooping cough germs can travel up to one metre in the air.
The classic childhood illness has therefore become a disease that now also affects many adults - usually unknowingly. Of course, for them and for older children, whooping cough is usually just a nuisance. Nevertheless, more severe symptoms such as weight loss, pauses in breathing and vomiting can also occur. The severe coughing can also cause sleep disorders, incontinence, haemorrhaging into the eyes or even rib, groin or umbilical hernias. Seizures and inflammation of the lungs and middle ear are known to be frequent complications.
Not to be taken lightly
Whooping cough is therefore not something that should be taken lightly as «a little cough». However, the greatest risk is that unvaccinated people pass on the pathogen to others, for whom whooping cough can be life-threatening. As newborn babies can only be vaccinated after the age of two months, it is all the more important that contact persons protect themselves against whooping cough: In addition to parents and siblings, this also includes grandma and grandpa, aunts, uncles or carers of older siblings.
A whooping cough vaccination booster is important because vaccination protection wears off over the years. «Neither a past illness nor a vaccination against whooping cough offers long-term protection against illness or re-infection and illness,» says Cornelia Feiterna-Sperling.
What do I need to consider if I fall ill?
- If you suspect that your child has whooping cough, be sure to inform the practice before visiting the doctor so that other patients can be protected from infection. If necessary, the doctor will prescribe an antibiotic. However, this can only alleviate the coughing attacks if it is taken early. Otherwise, you can only try to make it a little easier for your child to get through whooping cough.
- For example, it is important that they sit upright during a coughing fit and bend their head slightly forwards. Drinking plenty of fluids will help to alleviate the dry cough. It is best to divide the food into many small meals and snacks, as the constant gagging and vomiting make it difficult to eat during this time. Your child should not go back to school or nursery until at least three weeks after the cough begins to prevent infection. The best protection against infection is immunisation.
Doctors argue about how long a vaccination is effective. The rule of thumb is currently around ten years. However, vaccination protection does not simply disappear overnight. It can be assumed that it gradually diminishes over the years and the vaccinated person becomes more susceptible to the pathogen. The Swiss vaccination schedule recommends a total of six vaccine doses for basic immunisation: At the ages of 2, 4, 6 and between 15 and 24 months, then between 4 and 7 and between 11 and 15 years.
Adults are also recommended to have a single whooping cough vaccination between the ages of 25 and 29, but experts believe that this is not enough to achieve long-lasting protection. One way to further contain the pathogen would be a new vaccine with a higher level of effectiveness. Scientists are currently trying to find the immunological marker for whooping cough and to start developing a new vaccine. But even this can only work if people are vaccinated.
