LIVE POLIO IRUS VACCINES

224
Saf etv-Field Evidence of Saf ety
TABLE 12. DISTRIBUTION OF TIME INTERVALS BETWEEN FEEDING AND LAST VIRUS ISOLATION FROM
EIGHT INFANTS FED TRIVALENT ORAL LIVE ATTENUATED POLIOMYELITIS VACCINE* AT AGE 5-7 DAYS
AND SEVEN INFANTS FED AT AGE 2-5 MONTHS
NUMBER OF INFANTS
(FED AGE 5-7 DAYS)
NUMBER OF INFANTS
(FED AGE 2-5 MONTHS)
Ti T2 T, T2T 3 TT T 2 T2 T TT
0** 5 8 1 6 0 7 0 1
1 2 0 5 1 6 0 7 6
2 3 0 6 2 5 0 5 4
Time 3 3 0 3 1 5 0 4 2
in 4 1 0 1 0 3 0 5 2
Weeks 5 1 0 1 0 2 0 5 2
6 1 0 0 0 0 0 4 0
7 2 0 0 0 1 0 1 0
8 1 0 0 0 0 0 1 0
9 0 0 0 0 0 0 0 0
10 0 0 0 0 0 0 0 0
Total Infants 8 8 8 8 7 7 7 7
* 12 infants fed 1067' TCD 5 o each virus; 1 infant fed 106'7 TCDso each virus.
* *Zero indicates no isolations.
TABLE 13. VIRUS ISOLATION AMONG FAMILY CONTACTS OF SEVEN INFANTS FED TRIVALENT ORAL
LIVE ATTENUATED POLIOMYELITIS VACCINE*
Siblin Cont Lcts
Virus Isolated
Adult Contacts
Virus Isolated
Fed Age 5-7 Daye
(5 Infants)
T 1 T2 T
1 0 3
Totals
6
T 1 T 2 T
1 0 0
Totals
10
Fed Age 2-5 Months
(2 Infants)
0 0 2
3
4
Totals 1 0 5
9
1 0 0
14
* 1061 TCDs 5 each virus.
At least two changes are known to take place in
the first four months of life that could explain this
marked change in response to vaccination with
attenuated oral polioviruses. Good 7 has shown
that the newborn infant begins to produce gamma
globulin at about age 40 days. This production
increases rapidly until the infant is between 80-
120 days of age. At this age the gamma globulin
level is within normal range and the full im-
munologic capacity of the infant is nearly
reached. The antibody titer passively transferred
from mother to infant during intrauterine life
declines rapidly after delivery and at age four
months it is about one eighth (based on 37 day
half-life) of the titer of the cord blood. This new
ability of the infant to produce antibodies
coupled with the gradual loss of the protective
antibodies obtained from the mother makes the