Several years ago, the Centers for Disease Control and Prevention issued recommendations for informing college students about the severity of meningococcal disease, the increased risk for the disease among dormitory residents and the availability of an effective vaccine. Consequently, greater use of meningococcal vaccine is expected. As presently licensed, quadrivalent meningococcal polysaccharide vaccine is to be given by subcutaneous injection. Associated side effects include local injection-site reactions and headache. Previous studies of other vaccines have shown that intramuscular administration decreases local reactions without compromising immunogenicity. In a study carried out by the vaccine manufacturer (Aventis Pasteur), Ruben and colleagues compared intramuscular and subcutaneous administration of meningococcal vaccine.
The randomized study enrolled 141 healthy adults, of whom 133 completed the protocol. The average age of participants was 21 years, and most were white.
Local erythema of less than 1 inch occurred more frequently in participants who received meningococcal vaccine by subcutaneous injection (32 percent) than those who received intramuscular injection (11 percent). Headache occurred more often after subcutaneous injection (12 percent) than intramuscular administration (3 percent). Immunogenicity was evaluated by checking for at least a fourfold increase in antibody to meningococcal capsular antigens A and C. This fourfold increase occurred in 83 to 93 percent of study subjects and did not differ significantly for the two routes of administration.
Ruben and colleagues concluded that intra-muscular and subcutaneous routes were associated with similar immunogenicity. However, intramuscular administration of meningococcal vaccine had fewer associated minor side effects.