The study will evaluate the humoral immunogenicity in various schedule combinations of full dose inactivated polio vaccines (IPV) via intramuscular administration (IM) and of the fractional dose of inactivated poliovaccine (f-IPV) via intradermal administration (ID).
The study will be conducted in a setting where only IPV is being used for polio prevention in infant immunization schedules. The study population will include infants from Uruguay, a pioneer country in immunization programs in Latin America, where tOPV(trivalent oral polio vaccine) was used until 2012, after which the program changed to an all-IPV schedule without transition. The primary IPV immunization schedule in the country is as stand-alone vaccine at 2, 4 and 6 months of age, with a booster dose at 15 months. This setting allows the evaluation of IPV immunogenicity in a scenario where the circulation of any poliovirus is highly unlikely. Infants will receive two or three doses of full dose IPV IM or fractional dose f-IPV ID, in various schedule combinations (6 and 14 weeks; 10 and 14 weeks; 14 and 36 weeks; 6, 14 and 36 weeks; 10, 14 and 36 weeks). Immunological and safety assessments will be made after one dose, two doses and three doses. The study will be conducted in Montevideo, Uruguay and a total of 1493 infants will be randomized into 6 groups. Other vaccines comprise DTPw-HB-Hib (pentavalent combined diphtheria-tetanus-whole cell pertussis-hepatitis B-Hib vaccine), Pneumococcal conjugate vaccine, Rotavirus and will be administered concomitantly. Optimum immunogenicity expected from the dose/s of IPV in the post-eradication era will have to be balanced with the cost and supply constraints of IPV. This study will be critical to determine how many doses of IPV and which schedule will be recommended for the post-eradication era after the cessation of OPV (oral polio vaccine) usage globally.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
NONE
Comparison of different vaccination schedules with 2 different vaccines (IPV and f-IPV) and 2 different types of administration (IM and ID)
Comparison of different vaccination schedules with 2 different vaccines (IPV and f-IPV) and 2 different types of administration (IM and ID)
Seroconversion
Seroconversion will be defined as a change from seronegative to seropositive (antibody titers of ≥1:8) and in infants seropositive at baseline (assumed to be from maternally-derived antibody titers), as a ≥4-fold rise in antibody titers post-vaccination, computed by assuming an exponential decay model with a half-life of 24 days.
Time frame: To be assessed four weeks after the second vaccination for all groups receiving 2 doses of IPV and four weeks after the second vaccination for all groups receiving 2 doses of f-IPV.
Seroconversion
Time frame: To be assessed four weeks after the second or third vaccination, respectively, for the groups receiving IPV and four weeks after the second or third vaccination, respectively, for the groups receiving f-IPV.
Median titers
Time frame: To be assessed four weeks after the second or third vaccination, respectively, for the groups receiving IPV and four weeks after the second or third vaccination, respectively, for the groups receiving f-IPV.
SAEs (Serious Adverse Events)
Time frame: To be assessed throughout the complete study period, approx. 18 months.
IMEs (Important Medical Events)
These are medically significant events that do not meet any of the SAE criteria, but require medical or surgical consultation or intervention to prevent this event from becoming a SAE.
Time frame: To be assessed throughout the complete study period, approx. 18 months.
Severe local reactions
Severe local reactions can include severe pain, inflammation, induration and edema in the injection area.
Time frame: To be assessed throughout the complete study period, approx. 18 months.
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