TABLE 1
Universal Immunizations
A combination vaccine against diphtheria, teta-
nus, and pertussis (DTP) was first licensed in the
1940s. The initial vaccine consisted of diphtheria and
tetanus toxoids (a weakened form of the toxin that ac-
tually does the damage in the infections), and inacti-
vated, whole pertussis bacteria. As seen in Table 2,
tremendous reductions have been achieved in all
three diseases. Use of the original whole-cell pertussis
vaccine was marred in the past by concerns that the
vaccine could cause brain injury (specifically, an en-
cephalopathy). While this was largely disproven, the
concerns were enough to lead many people to refuse
the vaccine in the 1970s. In both Great Britain and
Japan, the decline in immunization coverage resulted
in epidemics of pertussis. In Great Britain alone,
more than 100,000 cases of pertussis occurred be-
tween 1977 and 1979. In both countries, vaccination
programs were restarted after the consequences of
low immunization rates were seen. In the United
States, a switch from the whole-cell pertussis vaccine
to an acellular preparation with significantly less fever
and local reactions was made in 1991.The first polio vaccine was the injectable, inacti-
vated polio vaccine (IPV) introduced in 1955. The
live-attenuated oral polio vaccine (OPV) was licensed
in 1960. Since the polio virus attacks the nerve cells
that control muscle movement, vaccines against polio
are responsible for enormous reductions in paralytic
poliomyelitis throughout the world, and for the eradi-
cation of natural polio infection from the entire west-
ern hemisphere. In the United States, the OPV was
used principally from the 1960s until 1997. Since
1997, a transition has been made to the IPV in order
to eliminate any chance of vaccine-associated paralyt-
ic poliomyelitis caused by OPV. IPV has no risk of202 IMMUNIZATION