LIVE POLIO IRUS VACCINES

520
Efficacy-Field Evidence
thing we could have done which resulted from
findings of our own research.
I do not, of course, feel justified to generalize.
The results and the decisions are based on our
actual investigations, making use of long-term
experience, and results of systematic field surveys
in which many specialists from different
branches participated. The purpose was to demonstrate
the methods we have used. And we
feel that these might have a more general validity,
though the final results may obviously differ
in different countries.
Within the last few hours I have tried to
sketch some simplified schedules applicable to
situations which could be found when using this
method of investigation (Fig. 7). The figure
logical point of view, these situations are very
dangerous and the epidemiological prognosis
of these countries, or parts thereof, is unclear.
Example No. 3 shows the typical situation
which can be found immediately after feeding
of attenuated vaccine: an extraordinary high
spread of viruses and low or no polio morbidity.
The last example is quite atypical. It shows
low spread of polioviruses and a high number
of paralytic diseases. Theoretically, two explanations
can be taken into consideration: either
incorrect sampling was carried out, or the
recorded cases are not poliomyelitis.
It is quite evident that an analogous situation
with different consequences may exist under
different conditions. This, however, is not the
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