ATLANTA Outbreaks of serogroup C meningococcal disease have occurred more frequently in the United States since the early 1990s, and the use of vaccine to control these outbreaks has also increased, according to the Centers for Disease Control and Prevention (CDC).
To combat this increasing problem, the Advisory Committee on Immunization Practices (ACIP) recently updated the guidelines for evaluation and management of suspected outbreaks of serogroup C meningococcal disease. However, the ability to validate some aspects of these recommendations is currently limited by incomplete reporting of serogroup information in most systems for meningococcal disease surveillance in the United States and the infrequency of serogroup C meningococcal disease cases and serogroup C meningococcal disease outbreaks, the CDC stated.
The decision to implement mass vaccination to prevent meningococcal disease depends on whether the occurrence of more than one case of the disease represents an outbreak or an unusual clustering of endemic meningococcal disease.
Mass vaccination can prevent unnecessary morbidity and mortality, and these guidelines are designed to determine whether mass vaccination should be implemented to prevent meningococcal disease.
Based on experience with serogroup C meningococcal disease outbreaks in the United States, the ACIP recommended the following 10 steps for evaluating and managing suspected outbreaks of serogroup C meningococcal disease:
Educating communities, physicians and other health care workers about meningococcal disease is also an important part of managing suspected outbreaks. Educational efforts should be initiated as soon as an serogroup C meningococcal disease outbreak is suspected, the CDC said.
Mass chemoprophylaxis can be considered, but is not effective in most settings in which community-based or organization-based outbreaks have occurred. Disadvantages of widespread administration of antimicrobial drugs for chemoprophylaxis include cost of the drug and administration, difficulty of ensuring simultaneous administration of chemoprophylactic antimicrobial drugs to large populations, side effects of the drugs and emergence of resistant organisms.
In outbreaks among small populations, administration of chemoprophylaxis to all those within this population may be considered. If mass chemoprophylaxis is undertaken, it should be administered to all members at the same time.
Restricting travel to areas with an serogroup C meningococcal disease outbreak, closing schools or universities and canceling sporting events are not recommended for controlling serogroup C meningococcal disease outbreaks, according to the CDC.
During 1980-1993, 21 outbreaks of serogroup C meningococcal disease were identified, eight of which occurred during 1992-1993. Each of these 21 outbreaks involved from three to 45 cases of serogroup C meningococcal disease, and most outbreaks had attack rates exceeding 10 cases per 100,000 population. This is approximately 20 times higher than rates of endemic serogroup C meningococcal disease, according to a recent Morbidity and Mortality Weekly Report.
During 1981-1988, only 7,600 doses of meningococcal vaccine were used to control four outbreaks, whereas from January 1992 through June 1993, 180,000 doses of vaccine were used for eight outbreaks.
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