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Mycoplasma pneumoniae infection

Mycoplasma pneumoniae infection

21 June 2019

Causative agent

It is caused by the bacterium Mycoplasma pneumoniae. Mycoplasma pneumoniae infection can occur at any time of the year. Community outbreaks may occur every 3 to 7 years.

Clinical features

Mycoplasma pneumoniae causes acute respiratory illness and the illness usually has a gradual onset over a period of 1 to 4 weeks. The majority of patients present with mild upper respiratory tract symptoms, such as fever, cough, sore throat, malaise and headache. Only 5 to 10% of infected patients develop atypical pneumonia. It is one of the most common causes of community-acquired pneumonia in otherwise healthy patients younger than 40 years, with the highest rate in individuals aged 5 to 20 years. Although Mycoplasma pneumoniae infection usually causes mild illness, severe complications such as severe pneumonia, encephalitis, renal impairment, and haemolytic anaemia may occur in some patients, especially elderly or immunocompromised persons.

Mode of transmission

Mycoplasma pneumoniae mainly spreads from person to person by coughing and sneezing through droplets of infected persons. It may also be spread by direct contact with the nose and throat discharges of an infected person; or indirectly through contact with articles freshly soiled by secretions of infected persons. Outbreaks usually occur in crowded institutional settings such as schools and residential homes.

Incubation period

The incubation period is commonly 3 weeks with a range of 1 to 4 weeks.


Most people recover from mild infection spontaneously. For pneumonia or severe infection, patients will be treated with antibiotics.


There is no vaccine against Mycoplasma pneumoniae available at the moment. As a general measure to prevent respiratory diseases, the members of public are advised to:

1. Maintain good personal hygiene

  • 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 sneezing or coughing. 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.

  • Build up good body immunity by having a balanced diet, regular exercise, adequate rest, reducing stress, do not smoke and avoid alcohol consumption.

  • Infected person should avoid contact with children, the elderly or those with weakened immunity.

2. 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 to 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 to 30 minutes and then rinse with water and keep dry. For metallic surface, disinfect with 70% alcohol.
  • Maintain good indoor ventilation. Avoid going to crowded or poorly ventilated public places; high-risk individuals may consider putting on a surgical mask while in such places.