LIVE POLIO IRUS VACCINES

9. IMMUNIZATION OF NEWBORN INFANTS WITH LIVE
ATTENUATED POLIOVIRUS VACCINE*
SAUL KRUGMAN, M.D., JOEL WARREN, PH.D., MARVIN S. EIGER, M.D.,
PETER H. BERMAN, M.D., RICHARD H. MICHAELS, M.D., AND
ALBERT B. SABIN, M.D.
Departments of Pediatrics and Obstetrics, New York University School of Medicine,
Department of Biologic Research, Chas. Pfizer and Co., and the Children's Hospital
Research Foundation, University of Cincinnati College of Medicine
DR. KRUGMAN (presenting the paper): Live
attenuated poliovirus vaccine was administered
to 400 newborn infants during a three-month
period (October 1959-January 1960). This study
was designed to obtain information which might
provide answers to the following questions: (1)
Would the ingestion of larger doses permit
enough of the vaccine viruses regularly to pass
the "acid barrier" of the stomach of newborn
infants and result in regular multiplication in
the intestinal tract? (Poliovirus may be destroyed
below a pH of 2.5 and the gastric contents
of newborns often have a pH of about 1.5);
(2) Would it be possible to by-pass the potential
handicap of high gastric acidity by swabbing the
vaccine directly on the posterior pharyngeal
wall?; (3) Would all three types multiply following
administration of a mixture of large doses
of Types 1, 2, and 3 poliovirus either by mouth or
by throat as determined by virus excretion and
antibody formation?
MATERIALS AND METHODS
Study Group. The study group included 400
infants born in Bellevue Hospital between October
1959 and January 1960. The mothers of
most of the infants were of Puerto Rican extraction
and came from a low socio-economic group,
a relatively immune population. Consequently,
it was likely that most of the babies would
possess passively acquired maternal poliovirus
antibodies.
Administration of Vaccine. The following
strains of Sabin's poliovirus vaccine' were em-
* Aided by grants from Chas. Pfizer and Co., and
The National Foundation.
315
ployed: (1) Type 1 (LSc, 2ab) containing 10`'°
TCD 50 ml.; (2) Type 2 (P 712, Ch, 2ab) containing
107.2 TCD50/ml.; and (3) Type 3 (Leon,
12a 1 b) containing 107.3 TCD,,/ml. The vaccine
was given orally in the various dosage schedules
listed in Table 1. It was administered by instilling
a measured amount on the back of the
tongue or by swabbing the tonsillar fauces and
posterior pharyngeal wall with an absorbent
cotton swab saturated with undiluted vaccine.
The first 330 infants were assigned in consecutive
rotation to the 11 different groups listed in
Table 1. The'last 70 infants were placed in
groups 5 and 10 and each llth infant was an
unvaccinated control. The first dose of vaccine
was given within 11 hours of birth. The second
dose was administered between 12 and 35 hours
and the third dose between 36 and 59 hours.
Collection of Specimens. Stool specimens were
obtained from most infants on the day of discharge
from the hospital, usually the fourth or
fifth day of life. In exceptional instances, specimens
were obtained as early as the second day
and as late as the 23rd day.
Cord-blood was obtained at the time of delivery.
Subsequently, at about three months of
age, a second blood specimen was obtained in
the Well Baby Clinic. The serum specimens were
kept in the deep freeze until paired samples were
available for antibody determination.
Virus Isolation Studies. Ten per cent stool extracts,
prepared as previously described, 2 were
tested in Rhesus kidney-tissue cultures in the
Cincinnati laboratory. When an initial test on a
total of 0.6 ml. of 10 per cent extract in three
tissue culture tubes was negative, the test was