Name of the study:

Administering neutralizing convalescent plasma to hospitalized patients with West Nile fever - a double-blind randomized controlled study.

The purpose of this study is to test the safety and effectiveness of giving blood plasma from convalescents rich in neutralizers as treatment against West Nile fever.

The study is performed in Sheba Medical Center ( and will be expanded in the soon future to other Medical centers in Israel).

Hospitalized patients diagnosed by blood/CSF PCR or IgM, with West Nile Virus will be recruited to the study.

After signing an informed consent they will be randomized (2:1) to receive either blood plasma rich in neutralizing antibodies or saline as placebo.

Number of participants in this center: 130 Age range: 60 years old and older, 18-60 years old with immunosuppression.

Inclusion criteria:

• Hospitalized patients with positive WNV-PCR with fever/neurological symptoms, and 72 hours have not yet passed since the positive result.
• Age 60 or older.
• Age over 18 and younger than 60 with immunosuppression (hypogammaglobulinemia, solid organ transplants, bone marrow transplants, hemato-oncological malignancies).

Exclusion criteria:

• Age younger than 60 without immunosuppression.
• More than 72 hours have passed since the diagnosis of West Nile fever.
• Pregnant women.

Reference to the inclusion of pregnant women, special populations - children and those lacking judgment- not relevant: excludes pregnant women and special populations.

The duration of the medical trial includes the follow-up period after the trial:

The duration of the treatment is one day, single dose of plasma/saline. The follow-up period is 90 days.

The clinical follow-up plan (during and at the end of the treatment):

A total of 10 visits will be conducted. On day 1, the following will be performed: screening, Medical history & Physical examination, IV Convalescent Plasma vs. Saline, Urine and blood for PCR, functional & neurologic assesment, IgG and IgM from serum, blood test for CBC & renal function.

On day 2-7 and 30 and 90, AE will be collected. On day 3, 5, 7 Urine and blood for PCR will be collected. Neurologic assesment will be conducted on all visits. Serology will be collected also on day 30 and 90.

After discharge, a follow-up visit will be performed either by a visit to the clinic or via phone call.

Inclusion Criteria:

• Hospitalized patients with positive WNV-PCR with fever/neurological symptoms, and 72 hours have not yet passed since the positive result.
• Age 60 or older.
• Age over 18 and younger than 60 with immunosuppression (hypogammaglobulinemia, solid organ transplants, bone marrow transplants, hemato-oncological malignancies).

Exclusion Criteria:

• Age younger than 60 without immunosuppression.
• More than 72 hours have passed since the diagnosis of West Nile fever.
• Pregnant women. Criteria for exclusion from the experiment: none Reference to the inclusion of pregnant women, special populations - children and those lacking judgment- not relevant: excludes pregnant women and special populations

The study will be conducted in a double-blind manner - the preparation/placebo will be provided by the pharmacy in a sealed bag.