The Next Pandemic?

Laurie Garrett

From Foreign Affairs, July/August 2005

Summary:  Since it first emerged in 1997, avian influenza has become deadlier and more resilient. It has infected 109 people and killed 59 of them. If the virus becomes capable of human-to-human transmission and retains its extraordinary potency, humanity could face a pandemic unlike any ever witnessed.

Laurie Garrett is Senior Fellow for Global Health at the Council on Foreign Relations and is the author of The Coming Plague and Betrayal of Trust.

The H5N1 strain of avian flu poses an additional problem: the virus is 100 percent lethal to chickens -- and that includes chicken eggs. It took researchers five years of hard work to devise a way to grow the 1997 version of the H5N1 virus on eggs without killing them; although there have been technological improvements since then, there is no guarantee that an emerging pandemic strain could be cultivated fast enough.

In the current system, all influenza vaccines must be quickly made following a WHO meeting of flu experts held every February. At that gathering, scientists scrutinize all available information on the flu strains known to be circulating in the world. They then try to predict which strains are most likely to spread across every continent in the next six to nine months. (This year the WHO committee chose three human flu strains, of types H3N2 and H1N1, to be the basis of the next vaccine.) Samples of the chosen strains are delivered to pharmaceutical companies around the world for vaccine production, and the vaccines are hopefully available to the public by September or October -- a few months after influenza typically strikes Asia, in the early summer. Europe and the Americas are usually hit shortly after, in September. Because viruses constantly change themselves, the process cannot be executed earlier in the year.

Although new technology may allow an increase in production capacity, manufacturers have never made more than 300 million doses of flu vaccine in a single year. The slow pace of production means that in the event of an H5N1 flu pandemic millions of people would likely be infected well before vaccines could be distributed.

GLOBAL REACH

The scarcity of flu vaccine, although a serious problem, is actually of little relevance to most of the world. Even if pharmaceutical companies managed to produce enough effective vaccine in time to save some privileged lives in Europe, North America, Japan, and a few other wealthy nations, more than six billion people in developing countries would go unvaccinated. Stockpiles of Tamiflu and other anti-influenza drugs would also do nothing for those six billion, at least 30 percent of whom -- and possibly half -- would likely get infected in such a pandemic.

Resources are so scarce that both wealthy and poor countries would be foolish to count on the generosity of their neighbors during a global outbreak. Were the United States to miraculously overcome its vaccine production problems and produce ample supplies for U.S. citizens, Washington would probably deny the vaccine to neighbors such as Mexico, since governments tend to reserve vaccine supplies for their own citizens during emergencies. Were the United States to falter, it would probably not be able to rely on Canadian or European generosity, as it did just last year. When the United Kingdom suspended the license for the Chiron Corporation's U.K. production facility for flu vaccine due to contamination problems, Canada and Germany bailed the United States out, supplying additional doses until the French company Sanofi Pasteur could manufacture more. Even with this assistance, however, the United States' vaccine needs were not fully met until February 2005 -- the tail end of the flu season.

In the event of a deadly influenza pandemic, it is doubtful that any of the world's wealthy nations would be able to meet the needs of their own citizenry -- much less those of other countries. Domestic vaccine purchasing and distribution schemes currently assume that only the very young, the elderly, and the immunocompromised are at serious risk of dying from the flu. That assumption would have led health leaders in 1918 to vaccinate all of the wrong people. Then, the young and the old fared relatively well, while those aged 20 to 35 -- today typically the lowest priority for vaccination -- suffered the most deaths from the Spanish flu. And so far, H5N1 influenza looks like it could have a similar effect: its human victims have all fallen into age groups that would not be on national vaccine priority lists, and because H5N1 has never circulated among humans before, it is highly conceivable that all ages could be susceptible. Every year, trusting that the flu will kill only the usual risk groups, the United States plans for 185 million vaccine doses. If that guess were wrong -- if all Americans were at risk -- the nation would need at least 300 million doses. That is what the entire world typically produces each year.

There would thus be a global scramble for vaccine. Some governments might well block foreign access to supplies produced on their soil and bar vaccine export. Since little vaccine is actually made in the United States, this could prove a problem for Americans in particular. Facing such limited supplies, the U.S., European, and Japanese governments might give priority to vaccinating heads of state around the world in hopes of limiting social chaos. But who among the elite would be eligible? Would their families be included? How could such a global triage be executed justly?

A similar calculus might be necessary for countries engaged in significant military operations. Troop movements would certainly help spread the disease, just as World War I aided the growth of the 1918-19 Spanish flu. Back then, the flu wreaked havoc on combatant nations. In the summer of 1918, influenza killed far more soldiers than did bombs, bullets, or mustard gas. By October, some 46 percent of the French army was off the field of battle -- ailing, dying, or caring for flu victims. Influenza death tolls among the various military forces generally ranged from 5 to 10 percent, but some segments fared even worse: historian John Barry has reported that 22 percent of the Indian members of the British military died.