3d.2 How common was HiB before routine vaccination, and how common is it now?
Description
This article is from the Childhood Vaccinations FAQ, by Lynn Gazis-Sax lynng@alsirat.com with numerous contributions by others.
3d.2 How common was HiB before routine vaccination, and how common is it now?
Before routine vaccination, about 12,000 cases a year in the US, with
a cumulative risk of 1 in 200 that a child would get the disease by
age 5. A vaccine was introduced in 1985. Since the introduction of the
Hib conjugate vaccine in 1988, the race-adjusted incidence of Hib
among children less than 5, has declined from 41 cases per 100,000 in
1987 to two cases per 100,000 in 1993. (The incidence for people five
or older remained stable. Hib is most serious in children under 5.) (A
decline of 95%, despite the fact that the National Health Interview
Survey showed only 67% of children 12-23 months had received at least
one dose, and 36% three or more doses. This decline is attributed to
the elimination of carriage, which reduces Hib exposure even in
unvaccinated children.) The CDC set a goal of eliminating Hib in the
US by 1996. (HICN708 Medical News, "[MMWR] Progress Elimination
Haemophilus influenzae type b") As of September 1999, this goal wasn't
met, but there has been a significant decline; MMWR's "TABLE
III. Provisional cases of selected notifiable diseases preventable by
vaccination, United States week ending September 11, 1999" records a
cumulative total for 1998 of 788 cases, and for 1999 of 820 cases, in
the US.
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