Secondary Attack Rate Measles Vaccine In Second Situation Contacts Cases Confirmed

Measles Clinical Trial

Official title: Secondary Attack Rate Measles Vaccine In Second Situation Contacts Cases Confirmed

Status Completed

Clinical Trial Summary

This study will be an epidemiological inquiry, in communicating confirmed measles cases. The contacts of the index cases will be asked about the measles diagnosis and previous measles vaccination, and will have their vaccination cards checked. They will also be asked about blocking vaccination (opportune or not opportune) and about the development or not of symptoms. Thus, the investigators will have a group of people exposed to infection with a history of vaccination for measles prior to the outbreak versus a group of people exposed without previous vaccination. The frequency of measles cases will be compared in those two groups, allowing to analyze the effectiveness of the vaccine for individual protection. The effectiveness of the vaccine in preventing the spread of the disease will be analyzed, comparing the relative risk of the vaccine history of contact, in the subgroups of index cases with and without previous measles vaccination. The proposed study will involve the collection and analysis of contact data from measles cases oriented to compare vaccinated and unvaccinated, differing from health surveillance actions. This is based on an exhaustive search for contacts of measles cases, preferably aimed at detecting susceptible individuals, with the purpose of implementing blocking vaccination and interrupting the transmission chain. The proposed study seeks a representation of contacts, without the intention of being exhaustive in the search and detection, but prioritizing selection without bias for one of the exposure groups (vaccination). The results may provide technical and scientific support for future decisions by the Ministry of Health regarding the primary immunization schedule, the priority of the age group in vaccination campaigns, the identification of susceptible individuals, and the assessment of the need for a 3rd dose of the vaccine, for measles.

Clinical Trial Description

This is a retrospective cohort study in which measles case contacts will be categorized according to their vaccination history and the secondary attack rate will be compared in vaccinated and non-vaccinated nodes. ;

Related Conditions & MeSH terms

• Measles

• NCT number: NCT05592756
• Study type: Observational
• Source: The Immunobiological Technology Institute (Bio-Manguinhos) / Oswaldo Cruz Foundation (Fiocruz)
• Status: Completed
• Start date: April 6, 2020
• Completion date: March 31, 2022