New Immunization Recommendations: “Meningococcus”
Dr. Jonathan Wood, MD
The Centers for Disease Control and the American Academy of Pediatrics recently released new recommendations for vaccination of older children and young adults against Neisseria meningiditis, a bacteria that causes severe illness in this age group. The common name for this organism is “meningococcus”.
The term “meningococcus” brings with it the picture of meningitis, a severe infection of the lining of the brain and spinal cord. This can be very confusing because the most severe form of disease caused by “meningococcus” doesn’t necessarily involve meningitis!
Here are some facts (1) about meningitis, (2) about the bacteria “meningococcus”, and (3) about the new vaccine and recommendations:
Meningitis Information:
Many viruses and bacteria cause meningitis. Some are preventable with vaccines and some are not.
Both types of meningitis are quite severe, but bacterial meningitis tends to cause more problems than viral meningitis.
Although we have antibiotics to treat most bacterial diseases, the problems from severe meningitis are often from the body’s own battle with the disease more than directly from the bacteria itself.
“Meningococcus” is only one cause of bacterial meningitis. For the last 10-15 years, we have regularly vaccinated against the other two big culprits, haemophilus and pneumococcus, decreasing their incidence dramatically. As a result, “meningococcus” has become the leading cause of bacterial meningitis in the US.
Most meningitis does not require preventive treatment of close contacts. Meningitis from haemophilus and from meningococcus are the 2 main types requiring such treatment of contacts.
“Meningococcus” Disease Information:
Although it is now the leading cause of bacterial meningitis in the US, the most severe form of “meningococcus” disease is NOT meningitis.
The most severe form of “meningococcus” disease is systemic or “whole body” disease. This is called meningococcemia. Meningococcemia is the form of “meningococcal” disease that progresses rapidly and has a high complication and death rate.
When a person is infected with “meningococcus”, there are 3 possible diseases patterns:
Meningitis
Meningitis with accompanying meningococcemia
Meningococcemia without clinical evidence of meningitis
Note: Of the 3 forms of disease, patients with meningitis alone fare the best
There are several types of meningococcus bacteria, usually described with letters (i.e. type B, type C, etc)
Type B Meningococcus causes a 1/3 of all cases and causes most cases in infants and young children
Most cases (>98%) of “meningococcus” disease occur sporadically, NOT as a result of an “outbreak”.
The Vaccine:
The newly licensed vaccine is a new form that stimulates the immune system better than previous varieties.
Type B Meningococcus (see above) is NOT covered by any vaccine.
The new vaccine recommendation: (CDC and AAP)
Young adolescents (age 11-12) should be vaccinated with the new type of vaccine (MCV4) at the preadolescent health visit.
Adolescents not receiving this vaccine at the preadolescent visit should be vaccinated before entry to high school.
Other “at risk” populations should also be vaccinated. Example include:
College freshmen living in dormitories
Military recruits
People without spleens or with certain immunodeficiencies
Some travelers (see the CDC website for traveler health information)
The older vaccine should be used for people “at risk” in the 2-11 year range and those greater than 55 years old.
Vaccines are also used as part of the control of outbreaks, when these uncommon occurrences occur.
For more information, contact your pediatrician
A helpful (and very complete) document from the CDC about the new recommendations:
http://www.cdc.gov/mmwr/pdf/rr/rr5407.pdf