Meningococcal disease

Overview

Meningococcal disease is an acute bacterial disease caused by Neisseria meningitidis (N. meningitidis). It can lead to serious illnesses such as meningitis and meningococcaemia, and can progress to death within hours.

Disease epidemiology

Meningococcal disease occurs worldwide. Those most at risk are infants, young children, adolescents, and young adults. The greatest burden is in the “meningitis belt” of sub-Saharan Africa where large-scale epidemics were previously caused by serogroup A. Introduction of a monovalent conjugate meningococcal A vaccine in 2010 reduced its incidence, with subsequent outbreaks caused by serogroups C, W and X.

Following introduction of serogroup C vaccines, serogroup B has become an increasingly common cause of meningitis globally. Singapore has a low incidence of meningococcal disease, with most cases in children aged below 5 years. The main serogroup causing disease locally is B. Singaporean travellers to high-risk countries, or to Mecca for the Hajj or Umrah, are at increased risk of exposure, which could be mitigated by vaccination.

Pathogen(s)

N. meningitidis (serogroups A, B, C, W-135, Y).

Transmission

Meningococcal disease primarily transmits through direct deposition of infectious respiratory particles (IRPs) such as when an infected person coughs or sneezes. It can also spread via contact with contaminated surfaces such as when IRPs settle on surfaces or transfer through direct contact (e.g. handshake) before reaching the mouth, nose or eyes.

Up to 5% to 10% of the population may be asymptomatic carriers with nasopharyngeal colonisation. Humans are the only reservoir for meningococcal infection.

Incubation period: Typically 3 to 4 days; ranging from 2 to 10 days.

Infectious period: Patients are infectious while there are live meningococci in secretions from nose and mouth. The bacteria are usually cleared within 24 hours of institution of effective antibiotic treatment.

Clinical features

Most commonly presents as meningitis with an acute onset of fever, headache, nausea and vomiting, stiff neck and photophobia. It may initially be mistaken for a flu-like illness.

Meningococcaemia is a severe infection characterised by petechial rash, shock, disseminated intravascular coagulation and multiorgan failure. Patients can have both meningitis and meningococcaemia. The onset of symptoms for these presentations is sudden and death can follow within hours.

Individuals with underlying immune dysfunctions such as asplenia, properdin deficiency, and a deficiency of terminal complement components are at increased risk. Case Fatality Rate can be as high as 15% even with antibiotics. 10% to 15% of survivors have persistent neurological defects, including hearing loss, speech disorders, mental retardation and paralysis. Less common forms of meningococcal disease include pneumonia, septic arthritis, and pericarditis.

Risk factors

Risk factors include:

• Age (children aged 1 years old and below, teens, young adults and elderly aged 65 years old and above)

• Relevant travel history to areas with reported cases or transmission of meningococcal disease e.g. to the meningitis belt in sub-Saharan Africa

• Participants of mass gatherings (e.g. Haj, Umrah Pilgrims)

• Immunocompromised individuals with immunodeficiency such as asplenia, HIV and terminal complement deficiencies

• Persons living in congregated settings e.g. dormitories

Diagnosis

Detection of N. meningitidis in sterile body fluids including blood, cerebrospinal fluid analysis, through isolation or polymerase chain reaction.

Treatment and management

Meningococcaemia and meningococcal meningitis are medical emergencies and admission to hospital is necessary. Early institution of appropriate intravenous antibiotics is critical to improve outcomes. Dexamethasone has not shown to be of any significant benefit in meningococcal meningitis.

Precaution, prevention, and control

Isolation measures

Standard and droplet precautions should be applied until 24 hours after initiation of effective antibiotic therapy.

Contact management

Post-exposure chemoprophylaxis of all close contacts is recommended. Healthcare workers generally do not require chemoprophylaxis unless they had direct exposure to patient’s secretions without the appropriate personal protective equipment e.g. intubation without respiratory protection.

Vaccination

There are different formulations of meningococcal vaccines available such as quadrivalent vaccines against serotype A, C, Y and W135, bivalent (A and C), or monovalent vaccines (A, B or C).

Meningococcal vaccination is a mandatory requirement for travellers to Saudi Arabia for the Hajj or Umrah pilgrimage.

Notification

Meningococcal disease is a legally notifiable disease in Singapore.

Who should notify:

• Laboratories

When to notify:

• On laboratory confirmation

How to notify:

• Please refer to the Infectious Disease Notification for more information.

Notification timeline:

• As soon as possible. No later than 24 hours.

Resources

Please refer to the Weekly Infectious Diseases Bulletin for the number of meningococcal cases in Singapore.

For more information on meningococcal disease, please refer to the World Health Organization website.

For general travel advisory, please refer to Health Advice for Travellers.