LIVE POLIO IRUS VACCINES

362 Efficacy-Laboratory Evidence
TABLE 6. VIRUS ISOLATION FROM PHARYNX OF PERSONS IVITH PREVACCINE ANTIBODY TITER OF 4 on
GREATER TO ONE OR MORE TYPES. HOUSES A AND D-RECEIVED UNENCAPSULATED VACCINE
TITER GREATER
TiiAN 4
TYPE
NUMEiu OF
PERSONS
11
III
VíIRUS ISOLATED)
I AND
11
I AND
II AND
III
1, II,
AND III
TOTAL NUMIBER
OF ISOLATES
NUMBER OF PERSONS
FROML WHOM VIRUS
WAS ISO1iATED
1 2
XO
X
3
II
3
XO
III
1
0
# XO
#XO
x
# O
I and II 1 5
XO
XO
x O
#
23
7
I and III 5
O
1
II and III 5
#X
#XO
S
3
I,II, and III 12
0
X
0
10
Total 43
51 *19
Suminary showing day aíld nuíbeor isolated by virus types
DAY I II ITI TOTAL ISOLATED
# 3 el 2 5 13
X 5 6 2 12 20
0 7 7 3 8 18
Total 19 25 5l
` Number of persons from whom virus isolated: 19/43 or 44.2%.
was less than four to all three types of virus.
Type 1 virus was isolated from four of five persons
with an antibody titer of less than four to
all three types of poliovirus (a ratio of 1:1.25),
from two of nine persons with antibody titers of
less than four for poliovirus Types 1-2 and 1-3
(a ratio of 1:4.5), and from one of 10 persons
with an antibody titer of less than four to Type 1
poliovirus (a ratio of 1:10). Type 1 virus was
isolated from the blood serum of seven out of 24
persons (a ratio of 1:3.4) with an antibody titer
less than four for Type 1 where this titer occurred
singly or in combination with poliovirus Types
2 and 3. Poliovirus Type 3 was isolated from
the blood serum of only one out of 44 persons
whose antibody titer was less than four for Type
3 singly or in combination with the other two
types of poliovirus. No Type 2 virus was detected
in the blood serum specimens tested.
DISCUSSION AND CONCLUSIONS
The dose form and the ingestion of trivalent
vaccine before or after a meal does not appear
to influence the antibody response. The high conversion
rate (81.2 per cent) experienced by the
participants in House B, the placebo-fed (control
group), is unexplainable at the present time.
Participants in this house were given unencapsulated
vaccine approximately one month later.
July 13, than participants in other houses, but
at the same time as placebo-fed (control) participants
in Houses A, C, D, and E whose antibody
conversion rate (57.9 per cent) was comparable
to participants who received the vaccine
approximately one month earlier. Two persons
in House B and two persons among the placebofed
groups in Houses A, C, D, and E showed an
antibody conversion during the control period