None listed
Conditions
Brief summary
The current World Health Organization (WHO) outbreak response guidelines recommend use of oral poliovirus vaccines (OPVs) to interrupt transmission of poliovirus outbreaks due to their ability to induce intestinal mucosal immunity. However, countries that exclusively use inactivated poliovirus vaccine (IPV) in their immunization schedules may be reluctant to reintroduction of OPV as it poses hurdles in both regulatory aspects and carries risk of seeding of vaccine-derived polioviruses (VDPVs). Additionally, the use of exclusive IPV was able to eliminate wild poliovirus in settings with higher sanitation and hygiene levels where oral-oral transmission dominates, likely through the induction of nasopharyngeal immunity. There is a limited number of studies that analyse nasopharyngeal mucosal immunity related to IPV: 4 interventional studies and 1 observational study during an outbreak in the USA. Furthermore, the studies have many limitations including undetectable virus in nasopharyngeal washings, interference with natural exposure to poliovirus and small sample sizes. Following a literature review conducted on the impact of IPV on mucosal immunity, the SAGE Polio Working Group recommended that a clinical trial is conducted to generate evidence on the impact of IPV on nasopharyngeal shedding, which can inform policy on the use of IPV-only outbreak responses in settings where oral-oral transmission dominates. Cuba provides a unique setting in which to evaluate the serological immunity because of the absence of wild polioviruses since 1962 and its unique strategy for administering OPV in annual campaigns. Poliomyelitis was eliminated from Cuba in the early 1960s. Since then, OPV has been administered to children through biannual NIDs. Each NID round lasts approximately one week during February and May, targeting all children aged greater than one month and less than 3 years with two doses of bOPV. OPV is not available at any other time of the year. In addition, previous studies in Cuba have shown that the attenuated Sabin virus contained in OPV disappears rapidly from the population after the second round of NIDs. For these reasons, the potential for “contamination” of the study arms by circulating OPV-like strains is minimized if not eliminated. Cuba was selected as study country because it is the only country in the world that satisfies two conditions: 1) OPV is administered exclusively in annual campaigns (leaving approximately 7 months of OPV-free environment) and 2) IPV is administered at 14 weeks of age but may be delayed up to 4 months of age. This fits well with the design of the study which seeks to understand viral shedding after poliovirus exposure (through an OPV challenge dose) in IPV-vaccinated children. Cuba is using fractional IPV administered intradermally at 4 and 8 months of age in their routine immunisation (RI) program.
Interventions
This is a two-armed study with an interventional (A) and a control arm (B). The intervention arm A will receive one full dose of Inactivated Poliovirus Vaccine (IPV) administered via intramuscular injection.
- IPV contents: 40 D antigen units of Type 1, 8 D antigen units of Type 2, and 32 D antigen units of Type 3 poliovirus.
- IPV Dose: 0.5 mL (full dose)
- Who will administer: local medical clinic nurse
- Where: at the local medical clinic
- When: between 6-8 months of age
All participants w
This is a two-armed study with an interventional (A) and a control arm (B). The intervention arm A will receive one full dose of Inactivated Poliovirus Vaccine (IPV) administered via intramuscular injection. - IPV contents: 40 D antigen units of Type 1, 8 D antigen units of Type 2, and 32 D antigen units of Type 3 poliovirus. - IPV Dose: 0.5 mL (full dose) - Who will administer: local medical clinic nurse - Where: at the local medical clinic - When: between 6-8 months of age All participants will receive the usual polio vaccines administered via routine immunization and national immunization days in Cuba (i.e., fractional-dose IPV administered intradermally at 4 and 8 months, one dose of bivalent oral poliovirus vaccine (bOPV) in the national immunization days). However, as a result of this study, administration of the second dose of fIPV will be delayed by 1 month. - fIPV contents: IPV contents: 40 D antigen units of Type 1, 8 D antigen units of Type 2, and 32 D antigen units of Type 3 poliovirus. - fIPV Dose: 0.1 mL (fractional dose)
Sponsors
World Health Organization
Study design
Allocation
Randomised controlled trial
Primary purpose
Prevention
Masking
Open (masking not used)
Eligibility
Sex/Gender
All
Age
6 Months to 8 Months
Healthy volunteers
Yes
Inclusion criteria
1. Healthy infants born June-August 2023 (i.e, 6-8 months of age at time of enrolment in February 2024) residing in Camaguey province of Cuba 2. Over the 3rd percentile for height and weight 3. Resident of the study locality for more than or at least 5 months, with no plans to move 4. Previously received one dose of fIPV in primary series at 4 months of age 5. Parent/guardian consent for participation in the study and for samples collection
Exclusion criteria
1. Infant not fulfilling inclusion criteria 2. Contraindication for venepuncture 3. Having received bOPV or 2nd fIPV dose before enrolment 4. Acutely sick child or child requiring hospitalization. These children will be referred to the nearest medical facility equipped to handle the case at their own expense. 5. Diagnosis or suspicion in the subject or an immediate family member of congenital medical conditions (e.g., Down Syndrome); primary immunodeficiency disorder; chronic medical illness (e.g., renal, cardiac) 6. Infants of mothers below the legal age (<18 years) or with mental incapacity will not be eligible to participate.
Outcome results
None listed