Preparing for a pandemic

Three recent outbreaks of avian influenza — the first two in Miyazaki Prefecture in Kyushu and the third in Takahashi, Okayama Prefecture — serve as a warning about a possible outbreak of an influenza pandemic that could cause millions of deaths worldwide. Virus samples taken from dead chickens in the first two outbreaks — Jan. 10 in the town of Kiyotake and Jan. 23 in Hyuga City — pointed to the highly pathogenic H5N1 strain as the culprit. This strain has pandemic potential because it is feared that it could mutate into a virus that can be transmitted from human to human.

Since the mutant virus would be new, people in general would have no immunity to it. The new form of influenza would spread quickly, causing more serious illness than normal influenza. The strain responsible for the third outbreak on Jan. 26 was found to be type H5.

According to the World Health Organization (WHO), 267 people have been infected with the nonmutant H5N1 strain in 10 countries since 2003; 161 of them have died. Indonesia has seen 62 deaths, the largest number, followed by 42 deaths in Vietnam, 17 in Thailand, 14 in China and 10 in Egypt.

Nine days after the bird flu outbreak in Kiyotake, the health ministry presented a panel of experts with draft guidelines designed to prevent a pandemic in the event of an outbreak of a new form of influenza. This will help people become conscious of the danger posed by the mutant H5N1 strain. The guidelines will be finalized by the end of March.

The government’s worst-case scenario indicates that 640,000 people would die in an influenza pandemic. On the basis of people’s behavioral patterns in the Tokyo megalopolis, the national Infectious Disease Surveillance Center estimates that a person returning from Southeast Asia to the nation’s capital carrying a new form of influenza could cause 120,000 people in Tokyo and four adjacent prefectures to be infected in just 10 days.

The 20th century witnessed three influenza pandemics: the Spanish flu in 1918, causing an estimated 40 million to 50 million deaths worldwide; the Asian flu in 1957, resulting in an estimated 2 million deaths; and the Hong Kong flu in 1968, taking an estimated 1 million lives. Utilizing Asian flu data, the WHO estimates that a new influenza pandemic would cause 2 million to 7.4 million deaths worldwide. Using Spanish flu data, the death estimate tops 100 million.

If there is an outbreak of a new form of influenza, the draft guidelines call for administering the antiviral drug Tamiflu to “patient zero,” his or her relatives and people in the person’s workplace or school to prevent the spread of the influenza. If the spread cannot be contained, the drug would be administered on a preferential basis to serious cases requiring hospitalization.

As for the administration of the drug to outpatients, the draft guidelines fix an order of priority: first, medical staff and those engaged in social services such as law enforcement, mass transit, city water supply, electricity and gas; second, high-risk patients; third, children and elderly people; and fourth, other adults. To make the plan effective, it would be necessary for the panel and the health ministry to narrow the definitions of priority types — a difficult task.

In administering a vaccine that will have been made before the outbreak, priority will also be given to medical staff and people engaged in social services. After an outbreak, a vaccine will be made from the new viral strain. In the initial stage, the amount of available vaccine will be small. Discussion of the issues of vaccination priorities and triage arrangements for hospitalization cannot be avoided. The ministry has submitted several options, including one giving priority to sick patients and another to children. The panel and the health ministry need to carefully listen to people’s opinions and make a reasonable decision that is acceptable to the public.

The sweeping character of the draft guidelines testifies to the expected seriousness of an outbreak of a new form of influenza. They call for isolating patients, closing schools, workplaces, theaters and other places where people gather, and restricting the movement of people in communities affected by the outbreak, including cutting off traffic to and from such communities if necessary. This means that individual citizens, enterprises and local governments must work together to contain the outbreak. The draft guidelines call on citizens to store a two-weeks’ supply of water, food and daily necessities.

Local governments clearly have a crucial role to play in the event of a potential pandemic. In refining the guidelines, the panel and the health ministry need to consider financial and other assistance to local governments so they can function properly.