How Effective Is the Vaccine for West Nile Virus?

There is no effective human vaccine for West Nile virus, although there is ongoing scientific research to find one. West Nile virus is a disease spread by mosquitoes which, in the minority of cases, may cause severe disease with neurological effects and even death. It was first reported in Africa but is now endemic to many parts of the US, Africa, Asia and the Middle East.

It is thought that the West Nile virus is contracted by humans from a mosquito which has previously bitten an infected bird. The first case in the US was reported in New York City in 1999 and it has since spread across the US. It seems to be more endemic during late Summer and Fall with a peak of reported cases in late August. Efforts to establish a vaccine for West Nile virus are ongoing.

In most people who have contracted West Nile virus, symptoms are mild and may even go completely unnoticed. A small percentage of those infected may get a mild form of the disease with symptoms such as headache, fever, body aches and, in some cases, swollen glands or painful eyes. In a very small number of cases the disease may have serious neurological complications such as meningitis or encephalitis, which may result in brain damage or death. Anybody experiencing neurological symptoms such as incoordination, confusion, seizures or stiff neck should seek urgent medical attention.

As there is no vaccine for West Nile virus, neither is there any direct treatment. It is not caused by a bacteria, so antibiotics have no effect. Treatment is purely symptomatic and to prevent complications and will be given in hospital under close medical supervision. People most susceptible to the severe form of the disease include the elderly or very young children, pregnant women and immunocompromised people, such as those with HIV.

Due to the lack of an effective vaccine for West Nile virus, preventative measures are the only way of avoiding the disease and these should be followed closely when in an endemic area. The main deterrent is to avoid mosquito bites. Measures include avoiding being outdoors during the times that mosquitoes most regularly bite, which is between dusk and dawn. Where possible, long sleeves and long pants should be worn and mosquito repellents should be used.

Reducing breeding places for mosquitoes can also reduce the risk of transmission. Removal of any still-standing water such as in pools or trash cans is vital. Due to the lack of a vaccine for West Nile Virus, these preventative measures and an awareness of symptoms and prompt treatment in the case of infection are very important.