Because
most measles vaccine failures are attributable to failure to respond to the
first dose, that all children receive two doses of measles-containing vaccine is
essential for the control of measles.
The purpose of the two-dose
vaccination schedule is to produce immunity in the small proportion of persons
who fail to respond
immunologically to one or more of
the components of the first dose.
During the 1980s, outbreaks of
measles occurred among school-age children in schools with measles-vaccination
levels of greater than or equal to 98% (18). Primary vaccine failure was
considered the principal contributing factor in these outbreaks.
Although some epidemiological studies
have shown slight increases in attack rates over time after vaccination with
live vaccine at 12 months of age or older, none has yet documented a significant
increase. During outbreaks, observed attack rates in persons vaccinated 15
years or more before infection have been on the order of 5% or less, and
calculated vaccine efficacies have generally been 90 to 95% or greater.
Since the initial recommendations for
a second measles vaccination were made in 1989, no additional epidemiological
evidence has emerged to suggest that waning immunity is a significant problem.
Boosting of prevaccination antibody titers, when it occurs, appears to be
transient (?). The major effect of the second dose appears to be in
immunizing persons who failed to respond to the initial dose (i.e., persons who
experienced primary vaccine failure).
ALL INFORMATION, DATA, AND
MATERIAL CONTAINED, PRESENTED, OR PROVIDED HERE IS FOR GENERAL INFORMATION
PURPOSES ONLY AND IS NOT TO BE CONSTRUED AS REFLECTING THE KNOWLEDGE OR OPINIONS
OF THE PUBLISHER, AND IS NOT TO BE CONSTRUED OR INTENDED AS PROVIDING MEDICAL OR
LEGAL ADVICE. THE DECISION WHETHER OR NOT TO VACCINATE IS AN IMPORTANT AND
COMPLEX ISSUE AND SHOULD BE MADE BY YOU, AND YOU ALONE, IN CONSULTATION WITH
YOUR HEALTH CARE PROVIDER.
"A foolish faith in authority is the worst enemy of truth."
-- Albert Einstein, letter to a friend, 1901
"I know of no safe depository of the ultimate powers of the society but the people themselves, and if we think them not enlightened enough to exercise control with a wholesome discretion, the remedy is not to take it from them, but to inform their discretion by education."
-- Thomas Jefferson, letter to William C. Jarvis, September 28, 1820
"What's the point of vaccination if it doesn't protect you from the unvaccinated?"
-- Sandy Gottstein
"Who gets to decide what the greater good is and how many will be sacrificed to it?"