Information

April 2001

Meningococcal Disease

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What is meningococcal infection?
Meningococcal infection is caused by a bacterium known as "meningococcus". Many people (approximately 10% of the population) carry meningococci bacteria at the back of the throat or nose without any ill effects. In rare instances, meningococci overcome the body's natural defences and cause serious diseases, including meningitis (infection of the lining of the brain) and meningococcemia, a widespread infection involving the blood and multiple organs.

How is meningococcal infection spread?
Meningococcal infection is not very contagious. The infection is spread from one person to another through a transfer of secretions from the throat or nose during close contact. Kissing, sharing eating utensils, drinking glasses, water bottles, cigarettes or sharing of lipstick can spread the disease. The infection is not acquired by simply being in the same room as an infected person or breathing air where an infected person has been.

Who gets meningococcal disease?
Most people exposed to the bacteria do not easily become infected, and even if infected, the majority do not develop any disease or symptoms. However, in a small number of cases the bacteria invade the body and produce meningitis, meningococcemia and other serious infections.

Although the disease can occur at any age, the highest risk for meningococcal disease is among children under one year of age with the next highest risk among teenagers 15 to 19 years of age.

What are the symptoms of meningococcal disease?
Meningitis symptoms commonly include high fever, headache, stiff neck, vomiting and drowsiness. Other symptoms include nausea, vomiting, dislike of bright lights (photophobia), confusion, drowsiness or a small purplish skin rash. In young children, the most noticeable symptoms may be marked behavioural change, such as drowsiness, irritability or excessive crying. These symptoms can develop over several hours or they may take 1 to 2 days. In people with meningococcemia without meningitis, the headache, neck stiffness and photophobia may be absent but the rash may be extensive, and may be associated with bleeding.

People who have had a sudden onset of these symptoms should contact their doctor immediately or go to a hospital emergency for diagnosis.

How serious is meningococcal disease?
Meningococcal disease is serious and sometimes fatal. Approximately one in ten persons who develop the disease may die. In addition, approximately one in ten persons who recover will experience some long-term effects such as deafness.

What is the treatment for meningococcal disease?
There are effective antibiotics for the treatment of meningococcal disease. It is important that treatment be started as soon as the disease is suspected.

How can we prevent the disease?
Most cases of meningococcal disease are unexpected and cannot be prevented. During an outbreak situation, preventive measures to reduce the transfer of infected throat or nose secretions, such as not sharing drinks, eating utensils, lipsticks, cigarettes may help reduce the risk. Regular, frequent hand washing is also a good practice.

Specific antibiotics are recommended to close contacts of the person with meningococcal disease, such as family members, the infected person's girlfriend or boyfriend, to prevent the development of disease and further spread of the infection.

Vaccines against several meningococci of types are available and may be used in an outbreak situation to provide more broad-based protection, for example in a school or community where there have been cases of meningococcal disease.

How effective are vaccines for meningococcal disease?
Current "polysaccharide" meningococcal vaccines, are 75% to 90% effective in adolescents and adults, approximately 50% effective in children 2 to 10 years of age, but provide no protection for children under the age of 2 years. The protective effect of the vaccine is short-lived, lasting 2 to 5 years.

New "conjugate" vaccines against group C meningococcus were recently used in mass immunization campaigns in the United Kingdom. These vaccines are safe and provide protection for infants, as well as for older children and adults, and is expected to result in long term protection. These vaccines are not yet available in Canada.

Is meningococcal disease on the rise?
The number of cases of meningococcal disease goes up and down in irregular cycles, with local and regional outbreaks occurring approximately once every 10 to 15 years. The last peak was seen in 1992 when over 400 cases were reported to Health Canada. From 1993 to 1999 the number of cases declined to less than 190 cases per year. During 2000, Alberta experienced an increase in meningococcal C disease. Since January 2001, an increase in meningococcal C disease has also been reported in Manitoba, Quebec and British Columbia.

What strains are causing outbreaks in 2001?
Meningoccocci are divided into various serogroups, including A, B, C, W135 and Y. Groups B and C meningoccoci cause most of the disease in Canada. Current outbreaks of meningococcus in Canada are due to "group C", which is vaccine preventable.

What is Health Canada doing to prevent the spread of meningococcal disease?
Health Canada works with the provinces and territories to monitor meningococcal disease across the country. Health Canada's National Microbiology Laboratory in Winnipeg tests samples submitted by the provinces and territories to rapidly identify cases and to determine which strains of meningococcal bacteria are causing disease. This information helps provincial, territorial and local public health authorities decide on the most appropriate approach to combat an outbreak. Health Canada also assists the provinces and territories in identifying the availability of current and new vaccines.

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