LIVE POLIO IRUS VACCINES

Vaccination and Challenge-Poliomyelitis in Nicaragua
553
85 per cent in 1958. Only two cases in the
country occurred in persons over ten years of
age and one of these was in Managua-an adult
European who died.
In Table 4, the attack rates for poliomyelitis
are shown for Nicaragua and Managua since
1951. During this period the rates for 1959,
both in Nicaragua, as a whole, and in Managua,
were the lowest experienced in the 10-year period.
LIOMYELITIS AND ATTACK RATES PER 100,000
POPULATION IN NICARAGUA AND THE
DEPARTMENT OF MANAGUA 1951-1960*
YEARS
NICARAGUA
MANAGUA
CASES RATES CASES RATES
1951 32 2.9 22 11.4
1952 24 2.1 20 10.1
1953 191 16.4 99 48.3
1954 45 3.7 28 13.2
1955 113 9.1 69 31.5
1956 48 3.7 36 15.9
1957 68 5.1 34 14.5
1958 256 18.6 107 44.1
1959 23 1.7 15 6.4
1960 202 13.6 98 33.5
* Up to 14 May.
POLIOMYELITIS IN VACCINEES
TABLE 4. REPORTED CASES OF PARALYTIC PO-
Among the 225 cases reported, 27 (or 12 per
cent) occurred in persons who received one or
more virus types by oral vaccination. Twentyone
of these cases were reported from Managua
and the remaining from the Department of
Chinandega (four cases), Masaya (one case),
and Rivas (one case) (Fig. 1 and Table 5).
No deaths were recorded among these 27 cases.
Table 6 shows the type of vaccine virus received
and the intervals between vaccination and the
probable date of onset of symptoms. It will be
noted that the longer intervals are associated
with the monovalent vaccine, the use of which
was discontinued in February 1959. There were
three cases which developed in children one
to nine days after emergency vaccination was
started in communities where no oral vaccine had
previously been used.
VIROLOGICAL STUDIES
In February 1960 arrangements were made
with the Middle America Research Unit in
Panama and the Viral and Rickettsial Research
Section of the American Cyanamid Company in
Pearl River, New York, to conduct virological
studies on stool samples from suspected cases
of poliomyelitis. An effort was made to obtain
specimens and clinical histories from all cases
as promptly as possible after the onset of symptoms.
However, in many instances the cooperation
of patients and families could not be se-
TABLE 5.
REPORTED
CASES OF PARALYTIC POLIOMYELITIS
IN NICARAGUA 1959-1960*
BY VACCINE STATUS AND AGE GROUPS
NICARAGUA
DEPARTMENT OF MANAGUA
AGE IN
YEARS
VACCINATED
NOT VACCINATED
VACCINXATED
NOT VACCINATED
Total
27
198
21
82