LIVE POLIO IRUS VACCINES

Discussion
323
vaccinated siblings in 16 out of 50 families, with
two or more children. Nineteen out of a total
of 75 contact children became infected.
The virus excreted by the contact children did
not show any increased virulence on intrathalamic
injection in monkeys.
Contrary to the excellent results obtained by
vaccination in infants over three months of age,
intestinal infection developed in only about 60 to
70 per cent of newborns and infants younger than
two months of age; however, those newborns and
young infants who became infected with the vaccine
virus developed as high antibody titers as
older infants, regardless of the level of passively
transmitted maternal antibody.
The following figures and tables give additional
data on the results obtained by the Swiss
group:
F. BUSER AND M. SCHAR, BERN
Antibody titer against Type 1 poliomyelitis virus
in 63 2-12 months old infants before and after
vaccination with avirulent Type 1 poliovirus
(CHAT strain).
>1000
a >200
*H -1000
.-
4.
0
o -200
0-5
es· o · · ·
*: * "***e
0-5 >5-50 >50-200 >200 >1000
-1000
titer after vaccination
F. BUSER, BERN AND R. MARTIN DU PAN, GENEVA
Level of antibodies against Type 1 poliovirus in
43 newborns before and after vaccination with
live avirulent polio vaccine Type 1 (CHAT
strain).
F. BUSER AND M. SCHXR, BERN
Persistence of antibodies against Type 1 poliovirus.
Retitration 2 years after the vaccination with
avirulent Type 1 vaccine (CHAT strain) in 20
triple negative infants.
O
o
>1000
oo
o**
>1000
-H +>
>200
a -1000
O
$ >50
-200
00 05 0@0 *S
U)
u-'
o'
r4
>200
-1000
>50
-200
00 *·ee
b
,
'4
-50
l a _ ·
0.5
o000 _ e I se ...
000
0-5
-5r 6 wU- afer vaccination 1000
Títer 6 weeks after vaccination
0-5
0-5 >5-50 >200 >50-200
0- ,5-50 > ;50-200 >200 >1000
-1000
* Virus excretora
o no virus excreted
Titer ia 1960