Antiviral drugs are medicines that act directly on viruses to stop them from multiplying. These are the drugs used to treat infections caused by viruses. Because viruses can only function within the cells of their hosts, it has been difficult to produce drugs that act specifically against viruses without damaging their host cells.
The effectiveness of antiviral drugs is therefore limited: frequently they will contain an outbreak of viral activity but are not capable of totally eradicating the infection, which can recur (as with cold sores). Fortunately, the majority of viral infections resolves spontaneously in most people and do not require specific medication. However, in immuno-compromised individuals, whose ability to fight infection is impaired because of drug therapy or disease like AIDS, antiviral treatment may be life-saving.
Many antiviral drugs act by interfering with DNA production and thus prevent the virus from replicating. The antiviral drugs are used to prevent or treat the diseases listed above. These drugs are specific for individual viruses and offer no benefit for conditions caused by other viruses.
For patients with symptoms of severe illness that are probably due to pandemic influenza, WHO recommends that treatment with oseltamivir should start immediately, no matter when the illness started and without waiting for laboratory results to confirm infection.
For patients at higher risk for serious disease from pandemic influenza, including pregnant women, children under age 5 and those with certain underlying medical conditions, WHO recommends treatment with either oseltamivir or zanamivir as soon as possible after the onset of symptoms, and without waiting for the results of laboratory tests.
People who are not from a higher risk group but who have persistent or rapidly worsening symptoms should be treated with antiviral. These symptoms include difficulty breathing or a high fever that lasts beyond three days.
Antiviral should only be used when prescribed by a qualified health care provider, as they will be able to assess each situation and make the appropriate decisions on care.
People who are not from a higher risk group and experience mild symptoms need not take antiviral. Most people recover from the pandemic influenza without the need for medical care.