LIVE POLIO IRUS VACCINES

10. RECENT EXPERIENCE WITH THE LEDERLE
TRIVALENT ORAL POLIOMYELITIS VACCINE
HERALD R. Cox, Sc.D., VICTOR J. CABASSO, Sc.D., JUAN EMBIL, JR., M.D.,
FLOYD S. MARKHAM, Pr.D., MAX J. MOSES, M.D., ARDEN W. MOYER, PH.D.,
MANUEL ROCA-GARCIA, M.D., AND J. M. RUEGSEGGER, M.D.
Viral and Rickettsial Research Section, Industrial and Community Relations Section,
and Medical Research Section, Lederle Laboratories, American Cyanamid Company,
Pearl River, New York, and Municipal Children's Hospital, Havana, Cuba
DR. Cox (presenting the paper): Since apparently
I am the only one given credit on the
program, I should also like to give due credit to
my associates, who are responsible, along with
me, for the data we are going to report today:
Dr. Victor Cabasso, Dr. Juan Embil from Cuba,
Dr. Floyd Markham, Dr. Max Moses, Dr. Arden
Moyer, Dr. Manuel Roca-García, and Dr. James
Ruegsegger. All these men, incidentally, are
members of the Pearl River staff, with the exception
of Dr. Embil.
INTRODUCTION
330
The increased incidence of paralytic poliomyelitis
in the United States during 1959, despite
the availability and use of large quantities of
formalin inactivated poliomyelitis vaccine, has
served to heighten interest in the oral method of
immunization with attenuated strains of polio
virus. In a recent publication namely, the British
Medical Journal, October 1959,' we briefly
reviewed the literature dealing with the simultaneous
application of multiple types of polio
virus and summarized the results of a small scale
trial of trivalent oral vaccine. Extensive field
trials with this type of vaccine, both in the United
States and in Latin America, as well as in Europe,
are now in progress and it is estimated that these
will comprise well over 1,000,000 persons by the
end of this year.
This report summarizes the completed serologic
study of paired sera obtained from three
separate groups of volunteers in different locations:
a series of 360 Cuban children, 123 members
of a closed institution in New England, and
933 persons, most of whom are Lederle employees
or members of their families. The trivalent
oral vaccine used in these studies was prepared
from the same virus strains previously described.'
Seventy-nine per cent of the 1,416
volunteers of the present study received vaccine
from a single lot; the remainder received vaccine
from two other lots which were similarly prepared
and administered. In all instances a single
2 ml. dose representing 1,200,000 tissue-culture
doses (106-1 TCD, 0 ) of each of the three virus
strains was fed. Blood samples were collected at
the time of vaccination and again four to seven
weeks later. Antibody levels were determined
by the metabolic inhibition test described earlier.'
Since this is a very important point, I would like
to state that in our case the paired sera were run
simultaneously, after they had been inactivated
at 560 for 30 minutes. We used four-fold serum
dilution, starting with 1:4 and ending at 1024.
We used 1/4 cc. volume of serum, to which we
added 100 to 300 tissue-culture doses of virus.
These mixtures were held at room temperature
for three hours, and then the cells were added.
In our laboratory, which is air-conditioned and
thermostatically controlled the year-round, the
temperatures vary between 70 and 750 F. The
cells were quantitated to contain, as nearly as
possible, 150,000 primary monkey-kidney cells
per 1/4 cc. volume always using Cynomolgus
monkey-kidney cells.
Our tests were carried out in duplicate tubes,
using the pH method.' We always used positive
and negative serum controls. I think it is quite
important to point this out.
There were no instances either in those who
were fed, or in their contacts, of illness or other
untoward manifestations attributable to the vaccine
and attention will therefore be confined to