West Nile Virus vaccine to enter safety trials in humans

8 Jul

The National Institutes of Health have announced that an experimental vaccine to

protect against West Nile Virus is to enter human trial.

vaccine by injection
The developers say because the vaccine uses inactivated virus it should be

suitable for a wide range of people.

The trial will test the safety of the vaccine – called HydroVax-001 – and its ability

to produce an immune response in human subjects.

In lab trials, the vaccine protected mice against lethal doses of West Nile Virus.

The tests showed the vaccinated animals’ immune systems responded with the

appropriate antibodies and CD8+ T cells, which bind to and kill infected


The randomized, placebo-controlled, double-blind phase 1 clinical trial will be

conducted by researchers at Duke University School of Medicine, Durham, NC, and is

expecting to enrol 50 healthy volunteers – men and women aged between 18 and 50 years –

by December 2015.

The participants will be randomly assigned to one of the three groups. One group of

20 volunteers will receive a low dose of the vaccine (1 mcg), another 20

volunteers will receive a higher dose (4 mcg) and a group of 10 volunteers will

receive a placebo.

All participants will receive their doses via intramuscular injection on day 1 and day

29 of the trial and will be followed for 14 months.

Vaccine uses inactivated virus

The vaccine was developed by scientists at Oregon Health & Science University (OHSU)

in Portland. The vaccine uses inactivated virus and cannot cause West Nile Virus


Led by OHSU senior scientist Dr. Mark Slifka, the team created the vaccine

using a new hydrogen peroxide process that inactivates the virus while preserving the

ability of key surface virus structures to trigger the appropriate immune


The researchers say that because the vaccine uses inactivated virus it should be

suitable for a wide range of people, including vulnerable groups like the elderly and

people with weak immune systems.

West Nile Virus is spread by mosquitoes in many parts of the world. It first emerged

in the Western Hemisphere in 1999 in the New York City area and has since spread across

the US.

Most people infected with the virus feel no symptoms, while around 1 in 5 feel like

they have the flu and experience mild symptoms such as headache, muscle ache and fever,

possibly with nausea and vomiting.

1 in 150 people infected with West Nile Virus experience serious problems

However, around 1 in 150 people who become infected with West Nile Virus experience

serious problems, including encephalitis (inflammation of the brain) or meningitis

(inflammation of the lining around the brain and spinal cord). In these cases the

infection can be fatal.

In the US, West Nile Virus infection is typically a seasonal epidemic that begins in

late spring or early summer and continues into the fall. 2,205 cases of West Nile Virus

infection and 97 related deaths were reported in 2014 in the US.

The vaccine trial is being sponsored by the National Institute of Allergy and Infectious

Diseases (NIAID), part of the National Institutes of Health. NIAID Director Dr. Anthony

S. Fauci, says:

“Since first appearing in the United States in 1999, West Nile Virus has

emerged as an important health threat in this country. NIAID is committed to research

efforts to advance a preventive vaccine that could protect people against West Nile Virus


You can see detailed information about the trial on the ClinicalTrials.gov website by

looking up the trial reference number NCT02337868.

Earlier this year, Medical News Today learned that public health experts are

warning that climate change could accelerate the arrival

in the UK of West Nile Virus and other diseases that are transmitted by mosquitoes

and other insects.

Written by Catharine Paddock PhD