When the World Health Organization announced on July 16 that it would stop issuing global counts of confirmed cases of the H1N1/09 virus (the new WHO-approved name differentiates the virus from older versions of H1N1), it wasn't because the disease had burned out. Far from it.
Since the new flu virus was officially declared a pandemic on June 11, the disease has spread faster in six weeks than past pandemics had spread in six months. Virtually every nation in the world has been infected, with the U.S. alone which has 263 confirmed deaths, more than any other country estimated to have logged more than 1 million cases. Although the good news is that most H1N1/09 illnesses have been extremely mild, the rapidity of its spread and the fact that young people seem to be especially vulnerable still worries global health officials. "We don't know if it will actually ever completely go away," says David Butler Jones, the public health chief of Canada, which has been unusually hard-hit. "We're still seeing new cases, so nobody should let down their guard."
The real test will come in the fall, however, when the Northern Hemisphere's flu season returns with a vengeance. (Southern Hemisphere nations are currently in the early weeks of their flu season, and H1N1/09 has caused real trouble in Argentina, which has more than 130 confirmed deaths second only to the U.S.) There is always a chance that the virus could become more virulent when it returns in the fall just as the deadly 1918 pandemic did. Key to the world's defense against the flu will be an effective vaccine, and vaccine companies have been gearing up to produce hundreds of millions of doses. Production is already under way, with the Australian drug company CSL this week becoming the first manufacturer to begin testing a vaccine in human subjects. "Things are proceeding well," says Jesse Goodman, the chief scientist and deputy commissioner of the U.S. Food and Drug Administration.
But vaccinemakers have already reported problems; the amount of antigen, the active ingredient in vaccine, reaped from each batch is only about 25% to 50% of the norm for seasonal flu vaccine. That means it will take longer to manufacture H1N1/09 vaccine and since very few people have immunity to this flu strain, people may need two shots, which means annual global capacity would drop to a little more than 400 million doses.
There is a way to get around this, by using adjuvants chemicals added to a vaccine that boost the immune system's response. That could stretch the world's capacity to more than 2 billion doses. But the U.S. has never licensed an adjuvated flu vaccine, which could delay approval in America. And while Europe doesn't have that problem, if Washington demands pure vaccine from its suppliers, that would affect supply for the rest of the world. For now, adjuvants are seen in the U.S. as a last resort. "Adjuvant use would be contingent upon showing that it was needed or clearly beneficial," says Goodman. "But we want them on the table."
Regardless, the U.S. Department of Health and Human Services doesn't expect to receive its first vaccines until mid-October, when flu season is already under way, so additional measures will need to be taken to control H1N1/09. In New York, by far the hardest-hit city in the U.S., plans include setting aside space in hospitals and clinics to screen potential flu victims before they flood emergency rooms. During the initial weeks of the spring outbreak, legions of the "worried well" those who mistakenly thought they had swine flu overwhelmed New York hospitals, leaving fewer resources for the truly ill. By trying to identify possible victims early, officials hope to keep hospitals running, mindful of the fact that accidents and other diseases continue even during a flu pandemic.
In Britain, the hardest-hit country in Europe, the government's chief medical officer caused a brief stir last week when he said that the National Health Service was preparing for a worst-case scenario of 65,000 deaths from the flu next winter. To prevent hospital overcrowding, the NHS is planning to allow people who think they might have swine flu to call a telephone line and answer a few questions; those whose answers indicate they might have it will be allowed to receive the antiviral Tamiflu or have a "flu friend" pick it up for them. (The system is available only in England for now sorry, Scotland.)
The biggest question will be what to do about schools. Because the virus has struck the young at such unusually high levels some 60% of the world's confirmed cases have occurred in people age 18 or younger schools have become a major locus of infection. Outbreaks incubate among children in schools, then spread to the community when those kids go home. A study in the journal Lancet found that closing schools as a preventive measure in the early stages of a pandemic could sharply cut the number of cases initially, which would reduce the later surges of infections that can overwhelm hospitals.
But that would come at a cost the Lancet researchers also estimated that a 12-week school closure could cost the U.S. as much as 6% of its GDP, and the burden would fall disproportionately on working families with few options for child care. For now, the WHO and national health agencies are hedging their bets. "School closing is one mitigation measure that could be considered by individual countries," says WHO spokesperson Alphaluck Bhatiasevi.
The simple fact that flu cases are still being recorded in the U.S. this summer, during a time when the virus should be virtually dormant, is a sign that things will get worse once the weather cools. The question is whether or not we'll be ready. "We're taking this virus very seriously, and I think it's important for the public to be thinking ahead," says Anne Schuchat, director of the National Center for Immunization and Respiratory Diseases at the Centers for Disease Control and Prevention. "This virus is not going away."