Medical Examiner

No Immunity

Why this year’s flu outbreak is a looming public health crisis.

Last week I wrote that if you weren’t getting a flu shot you likely had a feeble excuse. This week you’ve got a great one: The country has, for the first time ever, run out of vaccine. This public health crisis struck without warning. And make no mistake: It will be a crisis, with possibly thousands of deaths and hospitalizations. Officials at the Centers for Disease Control who are supposed to plan for such emergencies did not see it coming and have no plan to cope with it.

“This is the time for Americans to really step up to the plate and get vaccinated against influenza,” Dr. Julie Gerberding, CDC director, said at a Nov. 17 news conference. Less than three weeks later, the vaccine was almost all gone. Last Friday, the only two drug companies that manufacturer flu shots, Aventis and Chiron, quietly revealed that they had sold their entire stock. Officials at the CDC’s Atlanta headquarters then spent several frantic hours trying to find out how much remained in the pipeline—at distributors’ clinics and doctors’ offices. They called the health departments of the 24 biggest states and could locate only 80,000 doses out of the 83 million that had been made. Because it takes six months to manufacture flu vaccine, there will be no more for this season. The CDC’s advice to the public? A press release put out late Friday advised, “People wishing to be vaccinated may need to be persistent to find vaccine.”

How did the shortage occur? Amazingly, the CDC does not track vaccine supplies, even as it is urging people to get shots. Another problem is that drug companies alone determine how much vaccine to make, long before anyone knows how severe the season will be, and their decision is based on economics alone. Last year, a mild season, the drug companies made 96 million doses and had to destroy 13 million that went unused. So this year they made only 83 million. (A different company, Medimmune, made 5 million doses of FluMist, the new nasal spray vaccine, but it has not been approved for anyone under 5 or over 50, those who usually need it most.)

The stocks ran out this year, not because the public suddenly heeded the advice of the CDC chief and other health officials, but because the epidemic (a nasty new strain called the Fujian strain) hit harder and earlier than any strain has in three decades, with children especially suffering for reasons that experts do not yet understand. There have been at least 16 deaths and thousands of sick kids, many with severe, unusual complications. People who do not worry much about their own health will go to great lengths to try to protect their children; clinics across the country saw an enormous, unprecedented demand in shots for kids and their parents.

As the virus now spreads from its original epicenters in Texas and Colorado, many of those most at risk of dying from the flu—the old, the very young, and those with underlying medical problems—will not be able to get vaccinated. In addition, because health care workers have been notoriously lax about getting their shots (a mere one-third got vaccinated last year), we could soon be witnessing emergency rooms crowded with people violently ill with the flu and without enough medical staff to care for them.

Is such a drastic scenario inevitable? The virus could die out and not strike other places as hard as it hit the first states, but based on past years, that seems unlikely. Nowadays, doctors can also prescribe four antiviral drugs to treat and prevent influenza—but, no surprise, those already are in short supply because in many parts of the country where the vaccine has run out, doctors already have been using them, and there is no plan for ramping up production. If the epidemic does get very bad, our best defense will be thorough hand-washing and medical masks for health workers and patients brought into hospitals where there are not enough isolation facilities, but we could soon face a shortage of masks as well.

By the time the flu season wanes in April or May, congressional investigators will almost certainly be asking officials at the CDC and its parent agency HHS how we got into this mess. Why do we let market economics dictate a supply of 83 million doses of vaccine for a nation of 280 million? Why doesn’t the agency track remaining stocks?

Congress will also want to know about the composition of this year’s vaccine. As popular as it is, the vaccine does not quite match the nasty Fujian strain. It will take two or three more weeks before researchers finish a series of tests to find out just how much protection the vaccine has afforded those who managed to get it. Every year in early spring, the CDC together with the World Health Organization surveys the strains circulating in the world. Based on that information, an FDA panel decides on the composition of the vaccine to be manufactured for the fall. The Fujian strain had appeared by the time of this year’s survey, but the FDA panel decided against trying to get it into the vaccine because some panel members worried that trying to include it might create production delays.

Bad as they are, the difficulties in coping with this year’s influenza epidemic are like the tiny tremors in California that remind you of the looming Big One. In the world of influenza, the Big One is a pandemic—a strain of influenza so different from what has circulated before that people have no immunity. That’s what happened in 1918 when the flu killed between 20 million and 40 million people worldwide. Pandemics that killed well over half a million also struck in both 1957 and 1968.

One of the reasons that flu can become such a threat is that the virus passes easily from animals to humans and back again, often mutating in the process, and mutations often give rise to viruses to which people have less immunity. AIDS, Lyme disease, SARS, and Ebola all illustrate the threat to humans when, in the changing ecology of the world, viruses jump from animals to humans. With flu, it happens all the time.

Until 1997, researchers thought that flu viruses passed from birds (including migrating ducks that help spread it) to pigs to people. But a 1997 outbreak in Hong Kong showed that an avian influenza could directly infect and kill humans. Many hoped that outbreak—contained with a massive slaughter of chickens—was an isolated incident. But last year, in China and in the Netherlands, bird flu again infected and killed people and spread from person to person. Officials again contained the outbreaks by slaughtering thousands of chickens, isolating infected people, and in the case of the Netherlands, treating potential contacts of infected people with antiviral drugs. Last year’s bird flu outbreaks got far less attention than the 1997 incident because they occurred just before and during the Iraq war and the SARS outbreak. (As long as we’re contemplating health nightmares, we might think of what would happen if SARS returns during this bad flu season, when emergency rooms are filled already with people with similar symptoms.)

While one bird flu incident might have been interpreted as an isolated occurrence, multiple bird flu incidents increase odds that eventually an outbreak of a newly mutated strain will not be contained. The risk is exacerbated by the ever growing sizes of flocks kept in factory farming production. Dr. Robert Webster of St. Jude Hospital, an expert on influenza ecology, flatly predicts, “We will have a pandemic sometime in the next 10 years. The clock is ticking.”

But we can prepare. Modern molecular biology can learn to make vaccines much more quickly than the six months it now takes. We can stockpile enough antiviral drugs to treat the entire population. Those steps would require big investments for a risk that many believe to be hypothetical. But perhaps by end of this flu season people will realize just how dangerous influenza can be.