The National Institute of Allergy and Infectious Diseases (NIAID) has initiated a phase I clinical trial of an investigational vaccine designed to protect against yellow fever virus.
According to an NIAID statement, the study will evaluate whether an experimental vaccine developed by the pharmaceutical manufacturer Bavarian Nordic is “safe, tolerable and has the potential to prevent yellow fever virus infection.”
Bavarian Nordic’s experimental yellow fever vaccine, called MVA-BN-YF, is based on the company’s proprietary MVA-BN platform, which uses an attenuated version of the Modified Vaccinia Ankara (MVA) virus as a vaccine vector to carry yellow fever virus genes into the body. Bavarian Nordic says that more than 7,600 people, including 1,000 who are immunocompromised, have been safely vaccinated with MVA-BN–based vaccines.
The NIAID statement noted that prior studies have suggested that combining MVA-BN with ISA 720, an experimental immune-boosting adjuvant, induces a strong immune response after a single dose of vaccine. One goal of the study will be to assess whether two doses of unadjuvanted vaccine or a single dose of ISA 720 adjuvanted vaccine could provide protection against yellow fever.
NIAID said the placebo-controlled, double-blinded clinical trial will enroll 90 healthy men and women aged 18-45 years who have never been infected with a flavivirus. Participants will be divided into six groups: One will receive the currently licensed yellow fever vaccine (15 participants) and five groups (15 participants each) will receive the investigational Bavarian Nordic vaccine, either with or without an adjuvant. The investigational vaccine will be administered intramuscularly while the licensed yellow fever vaccine will be administered subcutaneously. Trial participants will receive one or two doses of vaccine or placebo, separated by a month.
According to NIAID’s statement , the multisite trial will be conducted by NIAID-funded Vaccine and Treatment Evaluation Units at the University of Iowa, Iowa City, and Saint Louis (Mo.) University. The Emory Vaccine Center in Decatur, Ga., will assist in evaluating data.
Yellow fever infection usually causes fever, back pain, headache, nausea, vomiting, fatigue, and weakness, but roughly 15% of infected patients develop severe disease manifested as jaundice, hemorrhage, and shock, resulting in potentially fatal kidney, liver, or heart conditions.
The current yellow fever vaccine can produce severe adverse complications, such as neurologic side effects, multiple organ system dysfunction and death, and thus cannot be given to infants, the elderly, pregnant women, and those with compromised immune systems. More than 105 million people in Africa have been vaccinated against yellow fever since 2006, according to the World Health Organization (WHO), but a new outbreak of the disease has caused an estimated 84,000-170,000 severe illnesses and 29,000 to 60,000 deaths in 2013.
For more details about the trial, visit the National Institutes of Health Clinical Trials website .
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