Pertussis

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Causative agent

It is caused by the bacterium Bordetella pertussis.

Clinical features

It is also known as ‘whooping cough’. The infected person may initially have non-specific symptoms like runny nose, sneezing, low-grade fever and mild cough. The cough gradually becomes more severe and spells of violent coughing can interfere with eating, drinking and breathing. The bacteria can cause lung infection, and even lead to seizures and coma in severe cases.

Mode of transmission

It is transmitted by direct contact with droplets from patients.

Incubation period

The incubation period ranges from 4 - 21 days, usually 7 - 10 days.

Management

Antibiotic is useful in treating the disease. A child who has persistent fever and cough with distressing gasp during the cough episode should be brought immediately to hospital.

Prevention

1. Vaccination

• Active immunisation with pertussis vaccine is an effective way to prevent the disease. In the current Hong Kong Childhood Immunisation Programme, a combined diphtheria, tetanus, acellular pertussis and inactivated poliovirus vaccine (DTaP-IPV) is used for preschoolers and Primary One students (Please refer to the Hong Kong Childhood Immunisation Programme). It offers good protection and the disease is milder in those who are infected after immunisation.
  
  
• Pregnant women are recommended to receive one dose of acellular pertussis-containing vaccine at any time in the second or third trimester, preferably before 35 weeks of gestation during each pregnancy as part of routine antenatal care regardless of previous vaccination and natural infection history against pertussis. This will provide direct protection for infants against pertussis through transplacental transfer of vaccine-induced antibodies from the mother before they receive pertussis vaccination.

• Perform hand hygiene frequently, especially before touching the mouth, nose or eyes; after touching public installations such as handrails or door knobs; or when hands are contaminated by respiratory secretion after coughing or sneezing.
• Wash hands with liquid soap and water, and rub for at least 20 seconds. Then rinse with water and dry with a disposable paper towel or hand dryer. If hand washing facilities are not available, or when hands are not visibly soiled, hand hygiene with 70 to 80% alcohol-based handrub is an effective alternative.
• Cover your mouth and nose with tissue paper when coughing or sneezing. Dispose of soiled tissues into a lidded rubbish bin, then wash hands thoroughly.
• When having respiratory symptoms, wear a surgical mask, refrain from work or attending class at school, avoid going to crowded places and seek medical advice promptly. 

3. Maintain good environmental hygiene

• Regularly clean and disinfect frequently touched surfaces such as furniture, toys and commonly shared items with 1:99 diluted household bleach (mixing 1 part of 5.25% bleach with 99 parts of water), leave for 15 - 30 minutes, and then rinse with water and keep dry. For metallic surface, disinfect with 70% alcohol.
• Use absorbent disposable towels to wipe away obvious contaminants such as respiratory secretions, and then disinfect the surface and neighbouring areas with 1:49 diluted household bleach (mixing 1 part of 5.25% bleach with 49 parts of water), leave for 15 - 30 minutes and then rinse with water and keep dry. For metallic surface, disinfect with 70% alcohol.