An antiviral stockpile is a reserve supply of essential antiviral medications in case of shortage. Many countries have chosen to stockpile antiviral medications against pandemic influenza. Because of the time required to prepare and distribute an influenza vaccine, 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, 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

Evidence-based medicine

Evidence-based medicine or evidence-based practice aims to apply the best available evidence gained from the scientific method to clinical decision making. It seeks to assess the strength of evidence of the risks and benefits of treatments and diagnostic tests...

 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, 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

Post-exposure prophylaxis is any prophylactic treatment started immediately after exposure to a pathogen , in order to prevent infection by the pathogen and the development of disease.-Rabies:...

 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

Oseltamivir INN , an antiviral drug, slows the spread of influenza virus between cells in the body by stopping the virus from chemically cutting ties with its host cell; median time to symptom alleviation is reduced by 0.5–1 day. The drug is sold under the trade name Tamiflu, and is taken orally...

 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, 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.

Rank	Country / Territory	Population	Treatments	Date Last Updated	Source
1	Mainland China	1,337,722,000
2	India
3	United States		50,000,000	April 27, 2009	Bloomberg.com Report of antiviral stockpile sales
4	Indonesia	230,014,115
5	Brazil
6	Pakistan	166,146,000
7	Bangladesh	162,221,000
8	Nigeria	154,729,000
9	Russia	141,833,393
10	Japan	127,630,000
11	Mexico	109,610,000
12	Philippines	92,226,600
13	Vietnam	88,069,000
14	Germany	82,062,200
15	Ethiopia	79,221,000
16	Egypt	76,030,000
17	Turkey	71,517,100
18	Iran	70,495,782
19	'	66,020,000
20	Early Modern France	65,073,482
21	Thailand	63,389,730
22	United Kingdom	61,612,300	30,000,000	April 28, 2009	BBC News Swine flu: How serious a threat?
23	Italy	60,090,400
24	Myanmar (Burma)	50,020,000
25	South Africa	48,697,000
26	South Korea	48,333,000	21,100,000	August 21, 2009	The Korea Times More Flu Virus Vaccines to Be Stockpiled
27	Ukraine	46,143,700
28	Spain	45,853,000
29	Colombia	44,830,423
30	Tanzania	43,739,000
31	Sudan	42,272,000
32	Kenya	39,802,000
33	Argentina	39,745,613
34	Poland	38,130,300
35	Algeria	34,895,000
36	Canada		1,400,000	April 27, 2009	Bloomberg.com Report of Antiviral Stockpile Sales
37	Uganda	32,710,000
38	Morocco	31,394,044
39	Iraq	30,747,000
40	Nepal	29,331,000
41	Peru	29,165,000
42	Venezuela	28,685,400
43	Malaysia	28,200,000
44	Afghanistan	28,150,000
45	Uzbekistan	27,488,000
46	Saudi Arabia	25,721,000
47	North Korea	23,906,000
48	Ghana	23,837,000
49	Yemen	23,580,000
50	Republic of China	23,027,672
51	Mozambique	22,894,000
52	Syria	21,906,000
53	Australia	21,745,000
54	Kingdom of Romania	21,496,700
55	Côte d'Ivoire	21,075,000
56	Sri Lanka	20,238,000
57	Madagascar	19,625,000
58	Cameroon	19,522,000
59	Angola	18,498,000
60	Chile		950.000	June 6, 2009	Ministerio de Salud de Chile Nueva Influenza Humana A (H1N1)
61	Netherlands	16,508,734
62	Burkina Faso	15,757,000
63	Kazakhstan	15,571,506
64	Niger	15,290,000
65	Malawi	15,263,000
66	Guatemala	14,027,000
67	Ecuador	13,938,115
68	Cambodia	13,388,910
69	Mali	13,010,000
70	Zambia	12,935,000
71	Senegal	12,534,000
72	Zimbabwe	12,523,000
73	Greece	11,262,500
74	Chad	11,206,000
75	Cuba	11,204,000
76	Belgium	10,741,000	3.000.000	1 Jan. 2007	Influenzahttp://www.influenza.be/nl/persberichten/2005-12-14_influenza_stock_antivirale_geneesmiddelen.pdf
77	Portugal	10,631,800
78	Czech Republic	10,474,600
79	Tunisia	10,327,800
80	Dominican Republic	10,090,000
81	Guinea	10,069,000
82	Haiti	10,033,000
83	Hungary	10,029,900
84	Rwanda	9,998,000
85	Bolivia	9,863,000
86	Serbia	9,850,000
87	Belarus	9,690,000
88	Sweden	9,264,000
89	Somalia	9,133,000
90	Benin	8,935,000
91	Azerbaijan	8,629,900
92	Austria	8,356,700
93	Burundi	8,303,000
94	Switzerland	7,705,800
95	Kingdom of Bulgaria	7,602,100
96	Honduras	7,466,000
97	Israel	7,411,000
98	Tajikistan	6,952,000
99	Papua New Guinea	6,732,000
100	Togo	6,619,000
101	Libya	6,420,000
102	Paraguay	6,349,000
103	Laos	6,320,000
104	Jordan	6,316,000
105	El Salvador	6,163,000
106	Nicaragua	5,743,000
107	Sierra Leone	5,696,000
108	Denmark	5,511,451
109	Kyrgyzstan	5,482,000
110	Slovakia	5,411,100
111	Finland	5,333,089
112	Turkmenistan	5,110,000
113	Eritrea	5,073,000
114	Singapore	4,839,400	500,000	April 28, 2009	Referenced. Confirmation expected.
115	Norway	4,814,075	1,400,000	April 28, 2009	http://blog.norway.com/tag/tamiflu/
116	United Arab Emirates	4,599,000
117	Costa Rica	4,579,000	3,000	April 28, 2009	Nacion.com (Spanish)
118	Republic of Ireland	4,517,800
119	Independent State of Croatia	4,432,000
120	Central African Republic	4,422,000
121	Georgia (country)	4,382,100
122	New Zealand	4,306,500
123	Lebanon	4,224,000
124	Puerto Rico	3,982,000
125	Liberia	3,955,000
126	Bosnia and Herzegovina	3,767,000
127	Palestinian territories	3,761,646
128	Republic of the Congo	3,683,000
129	Moldova	3,572,700
130	Panama	3,454,000
131	Uruguay	3,361,000
132	Lithuania	3,350,400
133	Mauritania	3,291,000
134	Armenia	3,230,100
135	Albania	3,170,000
136	Kuwait	2,985,000
137	Oman	2,845,000
138	Jamaica	2,719,000
139	Mongolia	2,671,000
140	Latvia	2,259,400
141	Namibia	2,171,000
142	Lesotho	2,067,000
143	Slovenia	2,053,355
144	Republic of Macedonia	2,048,900
145	Botswana	1,950,000
146	The Gambia	1,705,000
147	Guinea-Bissau	1,611,000
148	Gabon	1,475,000
149	Qatar	1,409,000
150	Estonia	1,340,341
151	Trinidad and Tobago	1,339,000
152	Mauritius	1,288,000
153	Swaziland	1,185,000
154	East Timor	1,134,000
155	Djibouti	864,000
156	Fiji	849,000
157	Cyprus	801,600
158	Bahrain	791,000
159	Guyana	762,000
160	Bhutan	697,000
161	Comoros	676,000
162	Equatorial Guinea	676,000
163	Kingdom of Montenegro	624,000
164	Solomon Islands	523,000
165	Suriname	520,000
166	Western Sahara	513,000
167	Cape Verde	506,000
168	Luxembourg	491,700
169	Malta	412,600
170	Brunei	400,000
171	The Bahamas	342,000
172	Iceland	319,326
173	Maldives	309,000
174	Belize	307,000
175	Barbados	256,000
176	Vanuatu	240,000
177	Netherlands Antilles	198,000
178	Samoa	179,000
179	Guam	178,000
180	Saint Lucia	172,000
181	São Tomé and Príncipe	163,000
182	Federated States of Micronesia	111,000
183	United States Virgin Islands	110,000
184	Saint Vincent and the Grenadines	109,000
185	Aruba	107,000
186	Grenada	104,000
187	Tonga	104,000
188	Kiribati	98,000
189	Jersey	89,300
190	Antigua and Barbuda	88,000
191	Northern Mariana Islands	87,000
192	Andorra	86,000
193	Seychelles	84,000
194	Isle of Man	80,000
195	Dominica	67,000
196	American Samoa	67,000
197	Bermuda	65,000
198	Marshall Islands	62,000
199	Guernsey	61,811
200	Greenland	57,000
201	Cayman Islands	56,000
202	Saint Kitts and Nevis	52,000
203	Faroe Islands	48,797
204	Liechtenstein	35,700
205	Monaco	33,000
206	Turks and Caicos Islands	33,000
207	San Marino	30,800
208	Gibraltar	31,000
209	British Virgin Islands	23,000
210	Cook Islands	20,000
211	Palau	20,000
212	Anguilla	15,000
213	Tuvalu	10,000
214	Nauru	10,000
215	Saint Helena	6,600
216	Montserrat	5,900
217	Falkland Islands	3,000
218	Niue	1,500
219	Tokelau	1,400
220	Vatican City	800
221	Pitcairn Islands	50