Active — Not RecruitingNot Applicable

Immunogenicity of Yellow Fever Vaccine in a Pediatric Population Vaccinated at 12-23 Months of Age in Argentina

Argentina361 participantsStarted 2022-12-06

Plain-language summary

Northern Argentina is a risk area for yellow fever (YF). Recent studies have suggested that immunity wanes in children vaccinated between 9 and 23 months of age. In 2015, a collaborative study conducted by the Ministry of Health (MoH) of Argentina, the Pan American Health Organization (PAHO), and the US Centers for Disease Control and Prevention (CDC) assessed the immunogenicity and safety of co-administration of YF and MMR vaccines in a pediatric population at 12-13 months of age. A total of 741 children presenting for routine immunization at 12-13 months of age enrolled and completed the study. It is now four to seven years since this pediatric group received their YF vaccinations. This cohort is unique because their initial YF vaccination and immune response to the vaccine dose are well characterized. Contact information collected during the earlier study will be used to locate the children. If consent is obtained, a 5ml specimen of blood will be collected and shipped to the CDC's Arboviral Diseases Reference Laboratory (ADRL) in Fort Collins, CO for plaque reduction neutralization testing using a 50% cut-off (PRNT50) to detect YF virus-specific neutralizing antibodies. Children with neutralizing antibody titers that are higher than their baseline titer collected approximately 28 days following YF vaccination will have PRNTs done for cross-reacting flaviviruses.

Who can participate

Age range

4 Years – 8 Years

Sex

ALL

See this in plain English?

AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.

Inclusion Criteria: * Children enrolled in the 2015 study received one dose of YF vaccine and had documented seroconversion regardless of the * Healthy child, determined by clinical history * Availability to perform a single blood draw * Informed consent signed by the parents. Exclusion Criteria: Children in the 2015 study received one dose of the Yellow Fever vaccine and had NO documented seroconversion. * Children enrolled in the 2015 study received a dose of the Yellow Fever vaccine and had documented seroconversion but, for different reasons, received a booster (minimum interval of one month between doses). * Children enrolled in the 2015 study received one dose of the Yellow Fever vaccine and had documented seroconversion but developed Yellow Fever * Children enrolled in the 2015 study received one dose of the Yellow Fever vaccine and had documented seroconversion but are participating in another clinical drug trial of a drug, vaccine, or medical device * Children enrolled in the 2015 study received a dose of the Yellow Fever vaccine and had documented seroconversion but, for various reasons, are immunocompromised: Weakened immune function, including HIV infection, primary immunodeficiencies, having received immunosuppressive doses of oral or injectable corticosteroids (or equivalent), having received immunomodulators or chemotherapeutic agents, disease of the thymus, Severe illness/fever (mild illness without fever is not an exclusion criteria) ● Any condition tha…

Questions worth asking your doctor

Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.

1Based on my diagnosis and history, is this trial worth exploring for me — or is there a standard treatment we should try first?
2What does this trial's phase tell us about how much is already known about its safety and benefit?
3What would taking part actually involve for me — visits, tests, time, and travel?
4What are the known and possible risks or side effects I should weigh, and how would they be monitored?
5If this trial isn't the right fit, what other options or trials would you suggest I look into?

Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.

Questions for the trial coordinator

The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.

1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?

A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.

What they're measuring

The proportion of the pediatric population seropositive for yellow fever ≥ 4 years after yellow fever vaccination at 12-23 months of age in Argentina.

Timeframe: 4-7 years following vaccination

Trial details

NCT IDNCT05644145

SponsorMinistry of Public Health, Argentina

Sponsor typeOTHER_GOV

Study typeINTERVENTIONAL

Primary completion2023-09-07

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