LIVE POLIO IRUS VACCINES

316
Efflcacy-Laboratory Evidence
316 Efficacy-Laboratory Evidence
TABLE 1. SCHEDULE FOR LIVE POLIOVIRUS VACCINE ADMINISTRATION
TO NEWBORN INFANTS
VACCINE
FED*
GROUP
METHOD
DoSE & DILUTION
OF VACCINE
D)AY
GIVEN**
TYPE 1
ONLY
1
2
3
4
5
MOUTIT
THROAT
1 cc undiluted
1 cc 1:10
Undiluted
0
0,1,2
0
0,1,2
0,1,2
TYPES
I+11+III
6
7
8
9
10
MOtUTH
THROAT
1 cce undiluted
1 cce 1:10
Undiluted
0
0,1,2
0
0,1,2
0,1,2
- l l I~ --
NONE
11
* Sabin strains
Type 1 (LSc, 2 ab)
Type 2 (P 712, Ch, 2 ab)
Type 3 (Leon, 12 a 1 b)
**0 = birth to 11 hours
1 = 12 to 35 hours
2 = 36 to 59 hours
repeated in an additional five tubes with an additional
1 ml. of stool extract. The isolates were
identified by appropriate neutralization tests. No
cytopathic agents, other than polioviruses, were
recovered.
Neutralizing Antibody Determinations. Tests
for antibody were carried out simultaneously on
the stored specimens of cord blood and on the
three-month specimens by the pH, metabolic inhibition
test at the Pfizer Research Laboratories.
The sera were tested in two-fold dilutions in
duplicate cups, and the titer was the dilution of
serum which neutralized the virus in both cups.
RESULTS
Clinical Observations. All 400 infants were
asymptomatic during the period of observation in
the nursery. No untoward reactions were reported
or observed in 270 infants examined at
the one month and three-month follow-up visits.
Virus Isolations on Single Stool Specimens.
The incidence of poliovirus isolations from single
stool specimens is shown in Table 2. Virus was
detected in about 80 to 90 per cent of the cases.
A single 1 cc. dose seemed to be as effective as
three daily 1 cc. doses of undiluted vaccine. Similar
results were also obtained with three daily
applications of undiluted vaccine by throat swab.
None of the stools of 31 control patients yielded
virus.
Extent of Poliovirus Multiplication. Table 3
shows the extent of poliovirus multiplication
after a single feeding of either Type 1 or of
trivalent vaccine. Stool specimens were obtained
from 20 infants two to 14 days after vaccine ad.
ministration. Ten infants received 1 cc. of
Type 1 undiluted vaccine; the remainder received
3 cc. of the undiluted trivalent mixture.
Feeding of Type 1 poliovirus vaccine was followed
by evidence of multiplication of virus on
the fourth, fifth, and eighth post-vaccination day.
The amount of virus recovered from the stool
ranged from 103 -2 to 104'.7 TCD 2 o per gram.
Triple-negative, five to 10-year-old children, who
had received 0.01 ml. of the same vaccine, excreted
104.7 to 106'2 TCD,, per gram of stool
at a comparable time."