An antiviral stockpile is a reserve supply of essential

antiviral medication Antiviral drugs are a class of medication used for treating viral infections. Most antivirals target specific viruses, while a broad-spectrum antiviral is effective against a wide range of viruses. Unlike most antibiotics, antiviral drugs do ...

s in case of shortage. Many countries have chosen to stockpile antiviral medications against

pandemic influenza An influenza pandemic is an epidemic of an influenza virus that spreads across a large region (either multiple continents or worldwide) and infects a large proportion of the population. There have been six major influenza epidemics in the las ...

. Because of the time required to prepare and distribute an

influenza vaccine Influenza vaccines, also known as flu shots, are vaccines that protect against infection by influenza viruses. New versions of the vaccines are developed twice a year, as the influenza virus rapidly changes. While their effectiveness varies fr ...

, these stockpiles are the only medical defense against widespread infection for the first six months. The stockpiles may be in the form of capsules or simply as the

active pharmaceutical ingredient An active ingredient is any ingredient that provides biological activity, biologically active or other direct effect in the diagnosis, cure, mitigation, treatment, or prevention of disease or to affect the structure or any function of the body of h ...

, which is stored in sealed drums and, when needed, dissolved in water to make a bitter-tasting, clear liquid. There are no evidence-based guidelines to guide the use of these stockpiled drugs, and plans are based on assumed similarities to seasonal influenza. The most common antivirals are

neuraminidase inhibitors Neuraminidase inhibitors (NAIs) are a class of drugs which block the neuraminidase enzyme. They are a commonly used antiviral drug type against influenza. Viral neuraminidases are essential for influenza reproduction, facilitating viral budding from ...

, which, if begun during the first 48 hours after symptoms appear, will reduce the duration of seasonal influenza by about one day. Taken before symptoms appear, it may prevent disease in about three-quarters of people treated prophylactically. Currently, this is recommended in institutionalized elderly people and other high-risk groups as a form of

post-exposure prophylaxis Post-exposure prophylaxis, also known as post-exposure prevention (PEP), is any preventive medical treatment started after exposure to a pathogen in order to prevent the infection from occurring. COVID-19 In 2021, the FDA has approved bamlanivi ...

during seasonal influenza outbreaks. However, since pandemic influenza differs somewhat from normal seasonal influenza, it is not clear that these drugs will prove either safe or effective for their intended purpose. For a person that has very recently been exposed to seasonal influenza, effective post-exposure prophylaxis generally requires taking a drug like

oseltamivir Oseltamivir, sold under the brand name Tamiflu, is an antiviral medication used to treat and prevent influenza A and influenza B, viruses that cause the flu. Many medical organizations recommend it in people who have complications or are at hig ...

for seven to ten days, at half the daily dose needed for treatment. A person that is repeatedly exposed, such as hospital staff members, may require continuous treatment throughout the duration of the outbreak in a community. Based on experience with seasonal influenza in

nursing homes A nursing home is a facility for the residential care of elderly or disabled people. Nursing homes may also be referred to as skilled nursing facility (SNF) or long-term care facilities. Often, these terms have slightly different meanings to in ...

, control of influenza requires full treatment of any ill persons and prophylactic treatment of all their contacts. In a pandemic situation, before a vaccine becomes available, this level of treatment and medical prevention may require providing drugs to 80% of the people in an affected community. Consequently, very large supplies of the drugs must be made available — much larger supplies than could be produced on demand. Stockpiles are generally arranged in advance by government health authorities, due to fear of shortages and an awareness of manufacturing limitations during an outbreak.

Supplies in each country

List of available treatments of antiviral per country.

References

{{Population country lists Anti-influenza agents Lists of countries