Ensuring the Safety of Yellow Fever Vaccination in Travelers-The Experience at a Large U.S. Academic Medical Center in Colorado.

Mehdi Bandali,William Mundo,Jonathan Schultz,Donna Mcgregor,Solana Archuleta,Elaine Reno,Carlos Franco-Paredes,Kimlien Than,Daniel Chastain,Sindhu Chadalawada,Andrés F Henao-Martínez

doi:10.3390/tropicalmed5030125

Abstract

Background: Yellow fever (YF) virus has the potential to cause fatal outcomes among at-risk individuals visiting endemic areas. Vaccinating travelers who are at risk is necessary to prevent virus-related life-threatening complications. We lack data on the clinical features of persons seeking YF vaccination. We aim to describe the characteristics of a cohort of persons receiving the YF vaccine before travel. Methods: A retrospective analysis of 964 travelers receiving the YF vaccine (Stamaril®) from Oct 2016 to Jul 2019 was performed at the University of Colorado Hospital, U.S. Percentages, means, and standard deviations were calculated. A multivariate logistic regression model was built to evaluate the association between receiving YF vaccination less than 10 days before departure and visiting friends and relatives (VFR). Results: The average age of the subjects was 39 ± 18 years with a range of nine months to 83 years. Persons who were 60 years of age and older represented 17%. Women consisted of 52%, and most of the travelers were Caucasians (64%). Travelers reported traveling to Africa (57%) or South America (40%). The primary destinations for travelers overall were Kenya (19%), Uganda (11%), and Tanzania (11%) in Africa; and Peru (14%) and Brazil (13%) in South America. The most common reasons for travel included leisure (44%), VFR (18%), and mission trips (10%). Comorbidities included a history of hematologic disorders (4%), HIV infection (2%), and diabetes mellitus (3%). The average duration between vaccine administration and travel was 43 days. Those VFR were two times more likely to receive the YF vaccination <10 days before departure. Conclusions: Identifying the type of travel, itinerary, and underlying medical conditions allows providers to administer the YF vaccine to travelers safely. There is a need to identify strategies to improve the timing of YF vaccination among VFR travelers.

Highlights

Yellow fever (YF) is a hemorrhagic disease caused by a flavivirus and transmitted by the Aedes aegypti mosquito, which is found in parts of tropical South America and sub-Saharan Africa
The YF vaccine is widely used for the prevention of YF in travelers, and for people living in endemic areas
Sanofi held the manufacturing of YF-VAX® in 2016 due to factory production issues, and the company made available an alternative vaccine, Stamaril®, which is administered in the U.S through an FDA-approved expanded access program

Summary

Introduction

Yellow fever (YF) is a hemorrhagic disease caused by a flavivirus and transmitted by the Aedes aegypti mosquito, which is found in parts of tropical South America and sub-Saharan Africa. The subgroup of patients traveling to visit friends and relatives (VFR) can be a vulnerable population at higher risk for some preventable infections, such as malaria, due to loss of previous immunity, and a lesser likelihood to seek pre-travel advice or take prophylaxis, while going back to their home countries [7,8]. This study aimed to identify important descriptors of patients getting the YF vaccine before travel, including patients traveling to visit friends and relatives. This information can aid public health agencies to enhance strategies to increase immunizations of patients at risk and avoid complications. There is a need to identify strategies to improve the timing of YF vaccination among VFR travelers

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