September 7, 2003, Updated September 13, 2012

The West Nile virus was eliminated in intentionally infected lab mice, and it has already promoted the recovery of a woman at Netanya’s Laniado Hospital.Israeli microbiologists have developed the first passive vaccine against the mosquito-borne West Nile virus, which has killed thousands and infected many more around the world. In the U.S. alone, it has killed 282 and infected 4,156.

The vaccine, called Omr-IgG-am, is effective for six weeks. It is based on a protein group found in the blood’s liquid component called immunoglobulin, which is taken from blood donors found to contain active antibodies against the virus, for which there is no available cure.

“This group contains all the antibodies that a human develops in his lifetime once he is exposed to bacteria, viruses and the like,” said team leader Professor Bracha Rager. Until recently she was chief scientist of the Health Ministry, and is also a veteran researcher at Ben-Gurion University of the Negev’s microbiology and immunology department. Her collaborator in the research was Dr. David Ben-Nathan of the Biological Institute in Ness Ziona.

The researchers succeeded in isolating the “defensive antibodies” produced from a group of proteins taken from Israeli blood donors who had come in contact with the virus. The antibodies were injected into mice who had been infected with the West Nile virus.

The disease was eliminated in the intentionally infected lab mice, and it has already promoted the recovery of a woman at Netanya’s Laniado Hospital.

As a result of their work, published in the July issue of The Journal of Infectious Diseases, the vaccine is about to undergo clinical trials at a number of American hospitals, under supervision of the US National Institutes of Health in Bethesda, Maryland. The trials are being carried out in cooperation with the Israeli biotechnology company Omrix, which has purchased the rights to manufacture the vaccine.

Rager’s team is currently working on an active vaccine that would have a more lasting and powerful effect.

“The research is pinned on our success in proving the effectiveness of the antibody
treatment against the disease. Not every disease can be treated in this way,” Rager said. “In the future, we will know how to produce immunoglobulins that will include the precise amounts of defensive antibodies and it will be possible to build a standard for the treatment of the disease. In addition, we will attempt to develop a vaccine for people who have not yet been infected by the disease.”

Until the late 1990s, West Nile virus was limited to Africa, East Asia, parts of the Middle East, and Europe. But in 2000, there were serious outbreaks in the US, Israel, and other countries. In Israel, a few dozen people died and hundreds were infected.

The disease appears as a flu-like condition, and is harmless to healthy people. But it can be deadly in individuals with weak immune systems, such as the chronically ill, the elderly, and young children.

The virus is found mostly in wild birds and sometimes mammals. People become infected by mosquitos which bite them after biting the mammals or birds. Infected people are liable to die from complications such as meningitis and encephalitis.

This year, despite the heavy rains, there have been only four reported cases of infection here. The authorities credit improved draining of standing water and insecticide spraying, as well as better protection (screens, mosquito repellant, proper dress) by those at high risk.

Rager told The Jerusalem Post that the initial results elicited skepticism among doctors, because the vaccine was tried on only a few patients. But the recovery of the woman from a coma after being vaccinated, despite having contracted chronic lymphocytic leukemia, led to the decision to conduct clinical trials.
Six other very sick local West Nile virus patients have been treated, and two (including a lung transplant patient) improved.

“If the high incidence of severe West Nile virus observed in 2002 in North America is repeated in coming years, there may exist a unique opportunity to determine whether early treatment… with [the] specific antibody is beneficial,” said NIH researchers. Rager added that approval of the vaccine is likely to be swift, not only because immunoglobulins are well known and used for other diseases, but also because the virus is spreading rapidly around the world.

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