LIVE POLIO IRUS VACCINES

Vaccination and Challenge-Poliomyelitis in Nicaragua 557
tory was confirmed. It may be noted in the
table that eight of these patients were vaccinated
during the mass vaccination program in Managua
in 1958, and they received all three types
of poliovirus as monovalent vaccines. The other
seven patients had received liquid trivalent vaccine.
These two groups will be considered separately.
Cases among monovalent-vaccine-fed children.
Cases Nos. 3 and 4, from whom fecal material
was not collected, recovered completely within
four months after the onset of paralysis. This
could suggest that the transient paralysis observed
was not due to poliovirus infection.
From the stool sample of case No. 7, a nonpoliovirus
agent was recovered in monkeykidney
tissue culture (MKTC). The sample was
collected 54 days after onset.
In case No. 8, from whom a stool specimen
was collected five days after onset, no agent
was recovered by any of the laboratories. This
fact may suggest an etiology unrelated to poliovirus.
Unfortunately, stool specimens were not
available from cases Nos. 1, 2, and 6. Serologic
results on two of these cases do not make it
possible to rule out poliovirus infection, and
these cases, therefore, could be considered as
vaccine failures.
Cases among trivalent-vaccine-fed children.
The onset of paralysis in cases Nos. 11 and 12
occurred within 48 hours after vaccine administration.
The onset of paralysis in cases Nos. 10
and 13, occurred 49 and 44 days, respectively,
after vaccine administration, and thus represent
onsets well beyond the accepted incubation perriod.(3)
They will be regarded as instances of
vaccine failure if the stool and blood studies
which are in progress confirm the clinical diagnosis
of poliomyelitis.
Cases Nos. 5 and 9 had onsets nine to 13 days
after feeding, and in spite of the fact that they
occurred within the period of the outbreak under
consideration, they deserve comment since both
might be suspected of vaccine strain etiology.
Case No. 5. Although this 32-month-old child
had had four injections of Salk vaccine, the last
one being eight months previously, she was fed
the trivalent vaccine on 11 December 1959. Her
illness had onset 13 days later and after four
days with a temperature of 38.5 ° C. she developed
paralysis in both legs and then quadriplegia
at which time she was hospitalized. One
week later she was sufficiently improved to be
taken home. Shortly thereafter her parents took
her to Mexico City for rehabilitation treatment.
After two and a half months she returned almost
fully recovered. She was seen in mid-May at
which time there was still some weakness in
the right deltoid and right leg, but without any
suggestion of muscular atrophy in either legs
or arms. The prognosis of the pediatrician who
treated her in Mexico City was for complete
recovery in 30 to 60 days. A stool specimen
from this patient, obtained 27 days after vaccination
and 15 days after onset, yielded Type 3
poliovirus. Neutralizing antibodies to all three
types of poliovirus were demonstrated in a
serum specimen which was collected on the same
date as the stool specimen. Available laboratory
data do not rule out poliovirus infection, but
the clinical evolution of this patient's disease
is rather suggestive of a non-poliovirus etiology.
Case No. 9. Poliovirus Type 1 has been isolated
from a stool specimen taken 11 days after
vaccination and two days after onset. Laboratory
studies are not yet complete and the case is
still under observation. The interval between
vaccine administration and onset, as well as the
fact that the virus isolated corresponds in type
to the one responsible for the epidemic, requires
that both natural infection and vaccine implication
be carefully studied. Investigations designed
to provide additional data for consideration
are still in progress.
In Table 7a the data are summarized for 12
paralytic cases for which the records for the
dates and types of vaccine administered are
incomplete or missing, or the patients failed to
receive all three types of virus. Cases Nos. 16,
17, and 18 received only vaccines for Types 2
and 3 during the mass vaccination program in
1958. Stools from cases Nos. 16 and 18 were
collected 25 and nine days, respectively, after
onset, and, when examined in MKTC one
yielded a non-poliovirus and the other no virus.
Type 1 poliovirus was isolated from case No. 17.
Because none of these three patients had received
Type 1 vaccine they may be dismissed
from further consideration.
Cases Nos. 21, 23, 25, and 27 were apparently
vaccinated as infants and are assumed to have
received one dose of monovalent vaccine, presumably
Type 2, since trivalent vaccine did not
come into use in Managua until sometime in