My teenage son recently started to smoke. Next year he will attend university. I read somewhere that both teens who smoke and first year university students who live in dormitories are at an increased risk of getting meningitis. Is that true? What can I do to reduce his risks overall?
You are indeed correct: cigarette smoking is a known risk factor for meningococcal disease, and students who attend university and live in dormitories are also at an increased risk. But the good news is that there is now a new vaccine available to cover the bacteria Neisseria meningitidis, which causes meningococcal disease or meningitis. The vaccine is known as Menactra.
The above question is very timely, but it is also an important opportunity to discuss the seriousness of meningeal disease in general. In Canada, there are three main types of bacteria which can cause meningitis: Pneumococcus, Haemophilus, and Neisseria meningitidis. Given meningitis is such a serious illness, there is a vaccine for each of these bacteria.
The clinical manifestations of meningococcal disease include any of the following: sudden onset of headache, fever, neck stiffness, nausea, vomiting, and an increased sensitivity to light (photophobia). In infants, the diagnosis may be harder to make because the onset of meningeal infections is often slower, subtle, and without neck stiffness.
When meningeal disease presents as a blood infection (meningococcemia), the situation is often quite dangerous. There is a sudden onset of fever accompanied by a typical rash known as petechiae (areas of pinpoint bleeding in the skin) as well as bleeding of the adrenal glands leading to shock, dropped blood pressure, and multi-organ failure. Meningococcemia carries a fatality rate of 20-40%. Survivors may end up with problems such as amputation, hearing loss, and neurological damage.
Becoming infected with Neisseria meningitidis can lead to meningococcal disease, mainly manifesting as meningitis or as meningococcal septicemia. In the latter, the patient has a very serious and life-threatening infection which spreads throughout the body via "seeding" in the blood. Neisseria meningitidis may also cause pneumonia and other infections, but these presentations are less common than meningitis and septicemia.
The bacterium Neisseria meningitidis, first isolated in 1887, spreads by droplets and enters the body via the nasopharynx (back of the throat). Some people may be asymptomatic carriers, which means they can harbor the organism in their throats but not get sick from it themselves. A study from John Hopkins University in Maryland suggests that adolescents in particular may spread this infection from their throats, via droplets, to younger children - a population especially at risk of getting meningococcal disease.
Other populations who are at increased risk include: people with weakened immune systems; those without a spleen (This organ may have been removed given significant bleeding in it due to blunt trauma to the abdomen, perhaps related to skiing, snowboarding or biking accidents); those infected with the human immunodeficiency virus (HIV); people living in overcrowded conditions; new military recruits; lower socio-economic populations; and those living in close proximity with a vast number of young adults, especially people aged 15 to 24 years.
A concurrent viral infection of the upper respiratory tract also increases the risk of meningococcal disease. This is probably due to an enhanced spread of respiratory droplets, but also because of diminished protection from the viral-damaged mucous membranes of the upper respiratory tract.
Humans are the only hosts of meningococcus. There are at least 13 serotypes of the bacteria, but only four are vaccine preventable: Strains A, C, Y and W-135. Menactra uniquely covers all four strains. Although strain B is another important strain, currently there is no effective vaccine available. Another vaccine for meningococcal disease, Menomune, only covers strain C.
In Canada, strain C accounts for 34% of invasive meningococcal disease (IMD); strains Y and W-135 now constitute 32% of cases. In Ontario, strain C is responsible for 24% of all IMD, whereas Y and W-135 comprise 40 % of all cases. In households where a case of IMD has occurred, the risk of invasive disease in family members is increased by a factor of 400 to 800.
The epidemiology of various strains of meningococcal disease in Canada continues to change regularly. This has prompted a prominent infectious disease expert, Dr. Ronald Gold from The Hospital for Sick Children in Toronto, to refer to it as "the influenza of bacteria in that it can change itself in response to the immune level of protection".
So far, Menactra has an excellent safety profile. The most common side effect reported is injection site pain. Given the vaccine has been available longer in the US, the Centers for Disease Control (CDC) has responded to reports of a very rare occurrence of Guillain-Barre Syndrome (GBS). The CDC states that results so far are inconclusive (there have been 17 reported cases of GBS following 6.6 million doses of Menactra vaccine), and continues to recommend vaccination with Menactra.
The vaccine schedule for children and adolescents is getting longer and longer each year. Last year marked the release of what some experts see as one of the most successful vaccines ever, Gardisal, which is expected to reduce cervical cancer by 70%.
The cost of Menactra varies from province to province. Thus far, there is no information as to the likelihood the Alberta Government will cover the cost of the vaccine in the near future.
More information on Menactra will be given to media outlets via press releases this week. Currently, Canadian doctors are receiving additional information on the vaccine in order to become more familiar with its benefits.
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