LIVE POLIO IRUS VACCINES

208 Safety-Field Evidence of Safety
208 Safety-Field Evidence of Safety
Vaccine. The vaccines used in this study were first inactivated for 30 minutes at 560 C. in a
liquid trivalent preparations developed by Dr. constant water bath. The serum samples were
Herald R. Cox and produced and provided to the then prepared in four-fold dilutions in duplicate,
authors by Lederle Laboratories. Each cubic 1:4 through 1:1024. Approximately 100 to 300
centimeter of vaccine contained 108 s TCD,,o ' of TCD,, of the representative strains of virus were
each of the SM (Type 1), MEF, (Type 2), and added to the respective serum dilutions and the
Fox (Type 3) strains of attenuated poliovirus. mixtures held at room temperatures for three
The attenuation history of these strains has previously
been reported by Cabasso et al. 2
The fol-
suspensions were added to each of the serum-
hours. Trypsinized monkey-kidney tissue cell
lowing lots of vaccine were used: a mixture of virus mixtures, and to appropriate controls. The
lots No. 7-1231-121, No. 7-1232-216, and No. tubes were kept at constant temperature of 37 ° C.
7-1233-318; lots No. 7-1238-800; No. 7-1238-801; and read on the sixth or seventh day. Antibody
No. 7-1238-801-2, and No. 7-1238-804A. - Vaccine titers were calculated by the method of Reed and
was dispensed in individual two cc. vials or by Muench. 4 By this technique a four-fold rise in
calibrated dropper from a 25 cc. multiple dose antibody titer is significant. Any titer of less
vial. All 0.5 cc. and 1.0 cc. doses were given by than 1:4 is considered unmeasurable.
the latter technique. All vaccine was stored at
constant temperature of 4 ° C. until used to
insure uniform potency.
Method of Administration. The vaccine was
poured from the individual 2.0 cc. dose vial or
squirted by dropper in the measured quantity
directly into the mouth of each participant and
followed immediately by a sip of water. Vaccination
at BMH and CIH was usually in the late
forenoon. All other feedings were at random.
Laboratory. At the time of vaccination, ten
cubic centimeters of whole blood was collected
with sterile vacumatic tube by antecubital
venipuncture. A second identical sample was
obtained about four to eight weeks after feeding.
About 7 per cent of those whose results are reported
here had the post-feeding specimen taken
before four or after eight weeks.
After clot retraction at room temperature the
specimens were centrifuged and the serum removed
by sterile pipette, placed in sterile serum
tube, frozen, and stored at -20 C. Any blood
specimens that did not have the serum separated
immediately were refrigerated at 4 ° C. until such
time as this separation could he done. When
sufficient numbers of paired serum specimens
accumulated they were shipped without refrigeration
by air express to the Viral and Rickettsial
Research Section of Lederle Laboratories, Pearl
River, New York for serological testing.
The method of antibody determination used
was the pH or color test according to the procedure
of Salk and Youngner. 3 All sera were
* Tissue-culture doses .
RESULTS
Pre-vaccination and post-vaccination antibody
titers were completed on 262 of the 310 participants.
The remaining 48 participants did not
have a post-vaccination specimen taken because
of discontinuance of care or delivery before a
three week interval had passed to allow antibody
response to the vaccine. Tables 1, 2, and 3
summarize the antibody titer responses of the
262 to the dosages of vaccine used. These tables
show a 39.1 per cent four-fold rise in titer to
Type 1, 30.9 per cent to Type 2, and 42.7 per cent
to Type 3. The two-fold or booster response
for each type is about 20 per cent higher. One
Type 1 and two Type 3 antibody determinations
were not done.
The per cent of significant response to each
immunotype for each of the three dosages of
vaccine used is shown in Fig. 1. Although these
data fail to demonstrate the superiority of the
largest over the smaller dosages, those participants
with unmeasurable antibody titers who
received 2.0 cc. of vaccine responded better (92
per cent) than did those who received 1.0 cc. (87
per cent) or 0.5 cc. (82 per cent). Although
these differences may indicate a trend, they were
not considered significant when subjected to
statistical analysis.
Of the 262 women with paired sera available
for serologic testing there were 72 (27.5 per
cent) with unmeasurable antibody titers to one
or more poliomyelitis immunotypes before vaccination.
These, together with their antibody
response to trivalent oral vaccine, are tabulated