Saturday, November 11, 2006

Prevention of meningococcal disease

Gardner P. NEJM 355: 1466-1473. Clinical Practice section.

N meningitidis colonizes the nasopharyx in 18 % of the population. Transmission is by droplet. Most adults have antibodies to the pathogenic subgroups (A,B,C,Y w-135). Classically infection occurs in crowded conditions, eg. military recruits. Infection occurs within 7-10 days of transmission and can be fatal. Occurrence is 0.5-1.1 per 100,000 population. Case fatality rate is 10 %. Sequelae occur in 11-19 % due to neurologic effects or DIC residua. 62 % occur in kids < 11. Other risk factors include crowding, RTI, active and passive smoking, asplenia, terminal complement deficiency. Travel to endemic areas such as Saudi Arabia or sub Saharan Africa also are risk factors. In year one of college rate is 5.1/100,000 but by year two its 1.4 or almost normal.

Chemoprophylaxs of close contacts: "Close contacts" are defined as people in 3 foot range (droplet range) or exposure through oral secretions including ventilatory tubing. For adults chemoprophylaxis is Copro 500 mg once, rifampin 600 q 12 for two days, or ceftriaxone 125 mg im onc if <15, 250 mg im once if older than 15. Chemoprophylaxis is indicated for vaccinated since vaccine does not cover all strains. Chemoprophylaxis should be undertaken within 24 hours.

Vaccines cover strains A,C, Y W-135 but not B. Two vaccines exist. Number one , Menomune (Sanofi) lasts 3 years and is good for travellers, people with limited risk (army recruits, college kids). Second one Menactra (also Sanofi) just released last two years, is more durable (lasts longer) and revaccination results in booster response. There is a warning on Menactra about GBS but it is not clear the 8 cases were more than would be expected in the population.

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