LIVE POLIO IRUS VACCINES

592
Discussion
592 Discussion~~~~~~~~~~~~~~~~
no Salk vaccine at all, as well as those who had
three or more doses; and two, to measure conversion
rates subsequently.
Among the children in the poor areas of the
city we bled at least 54 children who had had no
Salk vaccine at all and we found one interesting
thing: Type 1 poliovirus must have been spreading
among them during the past six months because
about 50 per cent in each group from
seven to 11 months, one to two years and two to
three years already had antibodies for Type 1.
It is therefore of interest that the only poliovirus
that we isolated among the small number
of agents recovered from the rectal swabs was
Type 1 poliovirus, which was present in the
community before we started the vaccination
program.
If we assume that rectal swabs are efficient only
to the extent of about 30 per cent, we might estimate
that just before feeding of the vaccine during
the last week in April, roughly 1 per cent of
the children in the poor areas of the city was
already disseminating Type 1 poliovirus.
I should like to elaborate further on the soil
on which the Type 1 vaccine was seeded. We
obtained records on every child not only regarding
his own extent of Salk vaccination but also
that of his parents and siblings.
The situation in Cincinnati is somewhat like
this in preschool children: among the preschool
children who had their own private physicians,
73 per cent had had three or more Salk vaccinations;
on the other hand, the children who came
to all the clinics, representing generally a mixed
group, only 54 per cent. But when we limited our
investigation to the children from the poorest
parts of the city, only 34 per cent had had three
or more doses of Salk vaccine.
Furthermore, it is also interesting to note
that among the children aged one to two years,
who had three doses of Salk vaccine, and who
were attended by private physicians, 34 per cent
had no demonstrable Type 1 antibody.
I limited this analysis to one- and two-year-old
children because (a) it would represent the more
recent vaccine used, and (b) it would also give us
only the children who had their last dose not
more than one year ago.
It was among this kind of population that,
within one week, about 75,000 preschool children
received the Type 1 vaccine only. The dose
was 200,000 plaque-forming units by actual titration
of a portion of the diluted vaccine used.
Two and a half to three weeks went by and
then, because New York State decided to carry
out a program on school children as well as preschool
children, Cincinnati demanded that all the
school children be included if enough vaccine
was available, and they were.
Within a matter of about four days, 90,000
school children received Type 1 oral poliovirus
vaccine, all of it being given in the schools after
permission cards had been obtained from the
parents. They just had a recess for vaccination,
and a whole school was covered in no time at all.
So it can be done very simply and quickly. Subsequently,
about 10,000 additional school children
in adjacent county schools also received
the vaccine.
It is now six weeks since the 75,000 preschool
children were fed the Type 1 vaccine and only
about three weeks since the school age children
were fed.
The school-age children had much more Salk
vaccinations-well over 80 per cent had three or
more doses.
But I think it is of interest also to look into
the contacts of the preschool children, with regard
to Salk vaccine status. We discovered that
46 per cent of the fathers, mostly young fathers
of these preschool children, had had no Salk vaccine
at all. Seventy-five per cent of the mothers
did have Salk vaccine, but of course, not all had
three doses. So there is a rather large contact
group among young fathers and mothers without
Salk vaccine protection.
We set up a very careful surveillance program,
supplying tubes and materials for the collection
of specimens on any suspect case of centralnervous-system
disease that might come into the
hospitals.
I should like to tell you that, prior to the beginning
of the program in Cincinnati, there was
only one reported case of clinical polio in 1960,
but the clinical diagnosis must be questioned. As
a clinician, I would not have made the diagnosis
of poliomyelitis on the findings in this case. It
had no pleocytosis. It had hyperactive reflexes
with a partial paralysis in one leg. Fortunately,