LIVE POLIO IRUS VACCINES

7. THE RESPONSE OF NEWBORN INFANTS TO VACCINATION
WITH LIVING TYPE 1 POLIOVIRUS (SABIN-LSc, 2ab)
PRELIMINARY REPORT*
MARTHA LIPSON LEPOW, M.D., ROBERT J. WARREN, M.D.,t NIGEL GRAY, M.B.B.S.,
AND FREDERICK C. ROBBINS, M.D.
Department of Pediatrics and Contagious Diseases
Cleveland Metropolitan General Hospital
and
Department of Pediatrics
Western Reserve University School of Medicine
Cleveland, Ohio
DR. ROBBINS (presenting the paper): The purpose
of this study is to investigate the response of
the newborn infant to vaccination with living
attenuated polioviruses. Newborn infants are to
be compared to those three months of age. The
influence of certain other factors upon the success
of vaccination is also being considered. These
include the antibody titer in the infant's blood at
the time of feeding and the acidity of the stomach.
Data are also being obtained relative to the persistence
of antibody, the immune response as determined
by the susceptibility of the bowel on
refeeding and by giving a booster injection of
killed vaccine, the spread of virus within the
family, and the genetic attributes of the virus
excreted by the infants as compared to those
of the virus fed.
Unfortunately, the investigation is still in its
early stages and relatively few data are available
at the time of writing. Therefore, this can be no
more than a brief preliminary report and will
concern primarily the pattern of virus excretion
and antibody response of newborns, as contrasted
with a group of three-month-old infants. Data
concerning the influence of serum antibody upon
virus excretion and a few observations on familial
spread of the virus will also be included. Because
of the preliminary nature of this report we
have not attempted to refer to the work of others.
* Aided by a grant from The National Foundation.
t Epidemic Intelligence Officer, Public Health
Service.
302
MATERIALS AND METHODS
Virus. The virus employed has been the Sabin
Type 1 (LSc, 2ab) strain and was obtained from
Dr. Sabin in sealed ampules of 1 ml. each. When
titrated in this laboratory in monkey-kidney cell
cultures, an ID,, of 10 - 7 .5 per ml. was obtained.
This agrees well with the titers observed on repeated
titration in Dr. Sabin's laboratory.
Each newborn infant received 1 ml. of virus,
or 107'5 TCID,, administered by dropper into
the mouth. In order to conserve materials, the
older infants have received 1 ml. of a 1:32 dilution
of the same virus, given in the same manner.
Antibody Determinations. Serum neutralizing
antibody has been determined by the metabolic
inhibition test of Salk, Youngner, and Ward.
Sera are diluted in twofold steps starting at a
dilution of 1:4, 100 ID 50 of virus are added to
each tube, and monkey-kidney cells are employed
as the indicator system.
COLLECTION OF SPECIMENS
Blood. Blood samples are secured from pregnant
mothers in the prenatal clinic one month to
six weeks before their expected date of delivery
and cord blood is collected in the delivery room.
A further sample is obtained from each infant at
the age of three months and additional ones will
be taken as indicated.
Those infants who are three months old at the
time of feeding are bled before the vaccine is ad-