A new day in preventing meningococcal disease: Sizing up the available vaccines

This review provides a brief overview of meningococcal disease, compares the characteristics of MCV4 and MPSV4, describes the indications for using the vaccines, and discusses recently raised concerns about the safety of MCV4.

A snapshot of meningococcal disease

Since the implementation of widespread immunization against Haemophilus influenzae type b and Streptococcus pneumoniae, N meningitidis has become the leading cause of meningitis among children and young adults in this country.⁴ Other clinical sequelae, such as pneumonia, septicemia without meningitis, occult bacteremia, and focal infections, also can follow infection with N meningitidis.

Symptoms vary somewhat with age. Older adolescents are more likely than infants to have shock and septicemia without meningitis at presentation, and to die.⁸

Transmission of N meningitidis occurs by respiratory droplets or direct contact with respiratory secretions (kissing, sharing drinking glasses, mouth-to-mouth resuscitation). Although invasive meningococcal disease draws the most public attention, it is believed that asymptomatic nasopharyngeal colonization with nonencapsulated, low-pathogenicity strains is actually the most common form of infection.^9-11 Colonization is thought to immunize most people; those who do not produce antibodies after colonization are likely still susceptible to future infection.¹² The colonization rate, which varies greatly with age, geography, and crowding, may be more than 20% in some populations.^9,13

In the US, the highest incidence of invasive meningococcal disease occurs in children younger than 1 year; a second, lower peak of illness appears in late adolescence (see Figure 1).⁴ Although the rate of disease is higher among the youngest children, most meningococcal illness (62%) occurs in children 11 years or older.⁴