Clinical Study of Immunity Duration of Yellow Fever Vaccine in Military

Completed

• Conditions: Yellow Fever Vaccine

• Registration Number: NCT03338231
• Lead Sponsor: The Immunobiological Technology Institute (Bio-Manguinhos) / Oswaldo Cruz Foundation (Fiocruz)

Brief Summary

Yellow fever is an acute viral disease transmitted by mosquitoes in South America, Central America and Africa. It is more prevalente in males gender and the age above 15 years due to the greater exposure in the wild endemic area of yellow fever.

According to the World Health Organization (WHO), a single dose of the yellow fever vaccine is sufficient to maintain protective immunity against yellow fever for a lifetime, therefore a booster dose is not required. This issue is difficult to evaluate because there is no serological correlate of protection against yellow fever and seropositivity is defined with several cut-off points. Although studies indicate that the duration of protection after vaccination is long, many studies have demonstrated a reduction of the antibody titrer over the years. Consequently, there is more concern about people who live in endemic areas. For this reason, Brazil recommends revaccinating once at least until additional studies are performed.

It is important to know the duration of immunity induced by lower doses of YF vaccine. In our knowledge, there is a lack of clinical studies evaluating the immunity duration of the yellow fever vaccine with lower doses. This information is relevant to subsidize the routine recommendation of YF vaccine fractional dose for adults.

Detailed Description

This is an observational study in young adult males who received the first dose of the yellow fever vaccine in 2009 when they participated in the "Dose-response study of the yellow fever vaccine 17DD produced by Bio-Manguinhos / Fiocruz.

Study Timeline

• Study Start: 2017-03-27
• Primary Completion: 2017-09-04
• Study Completion: 2017-09-04
• Status Verified: 2017-11
• Study First Submitted: 2017-11-01
• Study First Submitted QC: 2017-11-07
• Last Update Submitted: 2017-11-07
• Study First Posted: 2017-11-09
• Last Update Posted: 2017-11-09

Recruitment & Eligibility

• Status: COMPLETED
• Sex: Male
• Target Recruitment: 374

Inclusion Criteria

• Participated in the "Dose-response study of the yellow fever vaccine 17DD produced by Bio-Manguinhos / Fiocruz" in 2009.
• Not been revaccinated during the "Dose-response study of the yellow fever vaccine 17DD produced by Bio-Manguinhos / Fiocruz" of 2009.
• Not having received another dose of the 17DD yellow fever vaccine after participating in the 2009 "Bio-Manguinhos / Fiocruz" 17DD yellow fever vaccine dose-response study.
• Provide name, address, telephone and other information so that you can contact if necessary.
• Ability to understand and sign the TCLE.

Exclusion Criteria

• Impossibility or refusal to collect blood

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
Number of seropositivity participants to YF vaccine as assessed by PRNT.	8 years after the 1 st dose of yellow fever vaccine	To evaluate the seropositivity by the means of the neutralizing antibody dosage in the participants of the "Dose-response study of the 17DD yellow fever vaccine produced by Bio-Manguinhos/Fiocruz" realized in 2009

Secondary Outcome Measures

Name	Time	Method
Individual repertoire of immunoglobulins profile as assessed by the PEPperPRINT and phenotypic/functional anti-amaryl memory cell analyse.	8 years after the 1 st dose of yellow fever vaccine	To evaluate individual repertoire of immunoglobulins profile directed to amaryl epitopes by the PEPperPRINT (PEPperCHIP® Yellow Fever Virus Proteome Microarrays) Guidelines and to evaluate the phenotypic and funcional profile of anti-yellow memory cell in the participants of the "Dose-response study of the 17DD yellow fever vaccine produced by Bio-Manguinhos/Fiocruz" realized in 2009

Trial Locations

Locations (1)

Bio-Manguinhos/Fiocruz; 🇧🇷 Rio de Janeiro, Brazil