Sir.—Haemophilus influenzae type b (Hib) infection in children is responsible for approximately 12 000 cases of meningitis and 7500 cases of other invasive diseases annually in the United States,1,2 with a mortality rate of 5% in cases of meningitis and as many as 40% of survivors having significant neurologic sequelae.3
On October 4, 1990, the Food and Drug Administration (FDA) permitted one Hib vaccine manufacturer to amend its package insert to claim safety and efficacy for administration at age 2 months.4 The previous recommended age of first administration had been 15 months. The American Academy of Pediatrics (AAP) soon issued a recommendation for first administration to infants at age 2 months.
A letter called a Ped-Comm was sent from the AAP to its members in late October 1990 recommending the earlier age for first vaccination, but information on safety or efficacy was not included since