LIVE POLIO IRUS VACCINES

570 Efficacy-Fi eld Evidence
Two subsequent panel conferences reviewed
the 275 cases reported after the first meeting.
Of this total, all but 72 were rejected as being
without neurological content. The 72 cases
were segregated into non-polio cases with neurologic
signs and symptoms due to such diverse
causes as facial paralysis of unknown etiology,
a number of which had been seen before the
vaccination campaign started, polyneuritis, birth
trauma, tuberculous meningitis. There were
also cases of post-infectious encephalitis, meningitis,
and herpetic infection. Among these 72
cases were 53 which were accepted as paralytic
poliomyelitis. Forty-five of these were non-vaccinated
individuals and 14 had a history of oral
vaccination. The age distribution of these 59
cases is shown in Table 1. During the course of
the investigation of the neurologic cases, fecal
or blood or both types of specimens were examined
by the laboratories cooperating in the
program. In addition, stools and blood samples
from 62 household contacts of suspected cases
were investigated. Twenty-eight of the contact
specimens failed to yield any virus and from the
remainder, Types 1 and 3 poliovirus were isolated
once each, and Type 2 eight times. Nonpolioviruses
were isolated 17 times and results
of seven contact stool examinations are still
pending.
The results of the virological studies on the
stool specimens from the vaccinated and nonvaccinated
cases reported with confirmed neurologic
symptoms are summarized in Table 2.
Here it may be seen that polioviruses were isolated
from eight of the 49 non-paralytic cases
manifesting neurologic signs. Five of the eight
isolations were made from vaccinated individuals.
Three of the isolates were Type 1 poliovirus,
three were Type 2 and two were Type 3.
Other non-polio enteroviruses were isolated from
nine patients in the non-paralytic group.
Confirmed Poliomyelitis Cases. Of the 326
reported instances of suspected poliomyelitis
reported to the Surveillance Service and
TABLE 1.
PARALYTIC POLIOMYELITIS INCIDENCE
BY AGE IN COSTA RICA SINCE THE BEGINNING
(17 MARCH 1959 TO 17 APRIL 1960)
AGE IN
YEARS
10
Totals
OF THE ORAL VACCINATION PROGRAM-
VACCI-
NATED
5
5
2
1
o
o
1
14
CASES
NOT VAC-
CINATED
11
10
11
5
1
3
4
45
TOTAL
16
15
13
6
1
3
5
59
TABLE 2.
CASES WITH NEUROLOGICAL SYMPTOMS-RESULTS OF STOOL EXAMINATIONS
NON-PARALYTIC
PARALYTIC
ISOLATES
NOT
NOT
VACCINATED VACCINATED VACCINATED VACCINATED
TOTAL
Poliovirus Type 1
Poliovirus Type 2
Poliovirus Type 3
Other Enteric Virus
Negative
Pending
2*
2
1
3
1
2
1
1
1
6
26
3
0
5t
it
2
1
2
1 4
12 20
2 5
4 15
5 33
3 10
Total
11
38
11
27 87
* One case who received trivalent vaccine 16 days prior to stool collection.
t Includes one patient who received trivalent vaccine nine days before stool collection.