OPV Transmissibility in Communities After Cessation of Routine OPV Immunization

May 14, 2019 updated by: Yvonne (Bonnie) A Maldonado, Stanford University
The investigators propose to study both inter- and intra-household Oral Polio Vaccine (OPV) transmission in a primarily inactivated-polio vaccine (IPV)-vaccinated community in Mexico. The investigators will enroll 3 distinct clusters of households in a municipality in Orizaba, Veracruz, Mexico prior to the February 2015 National Immunization Week (NIW.) These clusters will be physically separate from one another and differ only in the proportion of OPV-eligible children who will receive OPV during the February 2015 NIW (10%, 30% and 70% vaccinated.) The investigators will look at inter-household and intra-household transmission. The investigators will then determine if epidemiologic (i.e.: degree of contact), anthropometric (i.e.: nutritional status) or clinical covariates (i.e.: IPV/OPV immunization history) are associated with intra-household transmission.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

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Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

We propose a prospective study to be conducted in 3 distinct clusters of 150 households each in one semi-urban municipality in Orizaba, Veracruz, Mexico during and after the February 2015 National Immunization Week (NIW.) Mexico provides a unique environment to study OPV transmission. The last case of poliomyelitis was reported in 1990. Mexico transitioned from an OPV to an IPV-based immunization regimen in 2007-2008. Currently, Mexican children receive IPV at 2, 4, 6, and 18 months of age. In addition, children ≤5 years old who have received at least 2 doses of IPV are eligible to receive OPV during biannual NIW held in February and May each year. Because of the changes in vaccination regimens over time, Mexican households consist of individuals with different degrees of susceptibility to OPV infection: those born before 2007 who were exposed to WPV and OPV or OPV alone, those born after 2007 exposed to IPV with intermittent OPV exposure, and un-vaccinated infants, some with maternal polio virus antibodies. By studying OPV transmission in this setting, we will be able to assess the impact of differing immunization status on OPV shedding and transmission.

We will conduct our study in a relatively isolated and semi-urban municipality of Orizaba, Veracruz, Mexico. These household clusters will differ only in the proportion of OPV-eligible children who will be OPV-vaccinated during the February 2015 National Immunization Week (10%, 30% and 70%.) We will enroll households that have at least 1 healthy child less than 5 years of age with an up-to-date IPV vaccination history. Enrolled households will then be randomized to the OPV-vaccinated or non-vaccinated arm of each household cluster. Eligible children from households in the OPV-vaccinated arm will then be further randomized to either receive OPV or remain un-vaccinated. Thus, only one child per household in the OPV-vaccinated arm will be vaccinated.

We will collect stool samples from all members of the enrolled households serially over the course of the study and will determine if individuals shed OPV in their stool using a serotype-specific real-time polymerase chain reaction (PCR) assay. We will define inter-household transmission as fecal OPV shedding by any member of a non-vaccinated household. By comparing inter-household transmission rates among all the household clusters, we will determine the if the proportion of OPV-vaccinated children impacts community OPV transmission in a primarily IPV-vaccinated community. These results will be critical to predicting the risk of OPV re-introduction in the event of a poliomyelitis outbreak in the post-OPV era.

We will define intra-household transmission as OPV shedding by household contacts living in vaccinated households. We will examine intra-household transmission in all clusters together to determine if certain characteristics are associated with transmission to household contacts. Elucidating these characteristics would allow for targeted interventions to reduce or prevent OPV transmission as cessation policy is implemented or in the event that OPV re-introduction is needed during polio endgame.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
1828

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

No older than 4 years (Child)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Households with children under the age of 5 who have up-to-date IPV vaccination history and willing to give informed consent and/or assent.

Exclusion Criteria:

  • Unwilling/unable to bring children's IPV vaccination records up-to-date.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Other
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: 10% OPV
In this arm, 10% of the households in this community will receive OPV.
Other: Controlling vaccination rates in communities
Three communities will be in three arms, one per arm. From 150 randomly-selected households, 10% will receive OPV in one community, 30% in the second community, and 70% in the third community.
Experimental: 30% OPV
In this arm, 30% of the households in this community will receive OPV.
Other: Controlling vaccination rates in communities
Three communities will be in three arms, one per arm. From 150 randomly-selected households, 10% will receive OPV in one community, 30% in the second community, and 70% in the third community.
Experimental: 70% OPV
In this arm, 70% of the households in this community will receive OPV.
Other: Controlling vaccination rates in communities
Three communities will be in three arms, one per arm. From 150 randomly-selected households, 10% will receive OPV in one community, 30% in the second community, and 70% in the third community.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Time Frame
Inter-household transmission of poliovirus
Time Frame: Feb 2015-May 2015; 4 months
Feb 2015-May 2015; 4 months
Intra-household transmission of poliovirus
Time Frame: Feb 2015-May 2015; 4 months
Feb 2015-May 2015; 4 months

Collaborators and Investigators

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Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Stanford University

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
Bill and Melinda Gates Foundation
Instituto Nacional de Salud Publica, Mexico

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
February 1, 2015

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
February 28, 2017

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
March 31, 2019

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
February 18, 2015

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
February 24, 2015

First Posted (Estimate)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
March 3, 2015

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
May 16, 2019

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
May 14, 2019

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
May 1, 2019

More Information

Terms related to this study

Keywords

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 31546

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