Disease factsheet about pertussis

factsheet

Pertussis is also known as whooping cough. It is a highly infectious bacterial disease involving the respiratory tract. It is caused by a bacterium (Bordetella pertussis or Bordetella Parapertussis ) that is found in the mouth, nose and throat of an infected person. 

Symptoms

Symptoms usually appear after 7 to 10 days after infection, but may also appear up to 21 days later. Initially, symptoms resemble those of a common cold, including sneezing, runny nose, low-grade fever and a mild cough.

Within two weeks, the cough becomes more severe and is characterised by episodes of numerous rapid coughs, followed by a crowing or high-pitched whoop. These episodes frequently end with the expulsion of a thick, clear mucous, often followed by vomiting. They initially occur at night and then become more frequent during the day and may recur for one to two months. In young infants the typical 'whoop' may never develop, and the coughing fits may be followed by brief periods when breathing stops. 
After this phase, the coughing fits become less frequent and less severe, and the infant gradually gets better although this can take up to three months.

 

Adolescents, adults, or partially immunised children generally have milder or atypical symptoms, so in these groups, in addition to very young infants, pertussis might be more difficult to diagnose.

Treatment

Supportive care following hospital admission is especially important for very young infants or older children with severe disease.

Antibiotic therapy is the treatment of choice for pertussis. However, in order to be effective, treatment must begin early in the course of disease, preferably within two weeks of onset. Antibiotic treatment can eradicate the bacteria from the nose and throat and limits the risk of it being passed on to others.

Complications

Complications of pertussis include pneumonia, middle ear infection, loss of appetite, dehydration, seizures, brain disorders, hernias, rib fractures, rectal prolapse, episodes of cessation of breathing. Severe cases can lead to death.

Fatalities caused by pertussis are most common in young infants, who die due to pneumonia or due to a lack of oxygen reaching the brain. Deaths are recorded every year in Europe, often are among infants who were too young to have been fully vaccinated. Less than one child in every thousand will die due to pertussis, however in many instances pertussis is not recognised as the cause of death, so it is possible that pertussis is responsible for a higher number of deaths than actually recorded. Almost all deaths recorded in Europe are in infants younger than three months. Between 2007 and 2012, an average of nine deaths per year were reported.

How common is pertussis in the EU?

Every year approximately 15–20 000 cases of pertussis are reported in the EU/EEA, with some countries reporting significantly more cases than others. It is difficult to compare the frequency of pertussis in different countries, because different methodologies for the diagnosis of pertussis are used. Also, cough due to pertussis is often not recognised as such. The number of cases of pertussis reported to ECDC has been increasing since 2011, reaching approximately 45 000 cases in 2012.

Ways to catch pertussis

Pertussis is primarily spread by breathing in droplets from the nose or throat of infected individuals. Pertussis can even be spread by an individual who has only a mild form of pertussis or by an individual who is asymptomatic.  Frequently, older siblings and parents who may be harbouring the bacteria bring the disease home and infect an infant in the household.

People most at risk

Pertussis can occur at any age. There is an increasing number of adults and adolescents who are diagnosed with pertussis. At present, the age groups with the most pertussis diagnoses are infants below one year of age, and adolescents between 10 and 20 years of age.

All those not vaccinated against pertussis with the recommended number of doses of vaccine are at risk, regardless of age.
Unlike diseases such as chicken pox (varicella) and measles, it is possible to have pertussis more than once during a lifetime, because the antibodies that are developed after infection do not last over time.

How to prevent pertussis

The most important way to prevent pertussis is through complete immunisation. The vaccine for pertussis is usually given in combination with diphtheria and tetanus (often in combination also with poliomyelitis, Haemophilus influenzae and hepatitis B). A primary course of three doses of DTaP (diphtheria, tetanus, acellular pertussis) vaccine or DTwP (diphtheria, tetanus, whole-cell pertussis) vaccine is usually given between two and twelve months of age. A fourth dose is recommended at 11–24 months of age and another dose between three and six years of age.

There is considerable variation between national immunisation schedules in the timing of these doses. Some countries recommend boosters for adolescents, during pregnancy or soon after delivery. Vaccine schedules in EU/EEA countries can be compared using ECDC’s Vaccine Schedule.

Is the vaccine safe?

The vaccines that protect against pertussis are generally safe. Minor adverse reactions can include local redness and swelling. Reactions such as fever, drowsiness, agitation and loss of appetite may also occur. Most of these problems resolve themselves. Less frequently, other reactions can occur, such as high fever, persistent crying lasting more than three hours (less than five in 1 000 vaccinations), fainting, an unresponsive collapsed-like state, and convulsions (less than 1 in 10 000 vaccinations). Most of these reactions have no long-term consequences.

In recent years, most EU/EEA countries have replaced the whole-cell type of pertussis vaccine with the acellular type as it is associated with fewer side effects.

What to do if you think you might have pertussis or if you have been exposed to pertussis

If you think you have pertussis, you should seek medical attention and inform the clinic in advance to avoid infecting other clients. Cover your mouth and nose to reduce the risk of spreading the infection to others.

An individual with pertussis can be infectious for four to five weeks from the onset of the illness. Treatment with antibiotics such as erythromycin can shorten the contagious period and limits the risk of infection to other people. People who have or may have pertussis should stay away from young children and infants until properly treated. Treatment of people who are close contacts of people with pertussis is also an important part of prevention.