What we can learn from the shortage of H1N1 vaccine.

Health and medicine explained.
Nov. 2 2009 2:35 PM

Blowing the Shot

What we can learn from the shortage of H1N1 vaccine.

H1N1 nasal vaccine. Click image to expand.
H1N1 nasal vaccine

The current shortage of the H1N1 swine flu vaccine was both predictable and largely avoidable. But it's not too late to remedy the situation. The last three pandemics—in 1968, 1957, and 1918—each lasted for more than three years, and this one is not going away any time soon. Now we must refocus public health priorities going forward, so we can apply the lessons of the swine flu to future outbreaks.

The first problem in preparing the H1N1 vaccine has been that we haven't yet transitioned to faster, more modern technology. Currently, the virus is grown in hen eggs, a laborious process that dates back to the 1950s. Culturing the virus in mammalian cells and using genetic splicing techniques to speed the manufacturing process, as we do with other vaccines, would be helpful for staying ahead of a burgeoning pandemic. Congress allocated more than $1 billion to five manufacturers in 2006 for this purpose, but they've been slow to make the change. Even when vaccines are done, they must face the FDA, which is slow to approve the latest vaccines—in part because of saber-rattling fear mongers who view any vaccine as an aliquot of poison.

The slow process is compounded by the fact that our health officials believe too much in the old technology. The Centers for Disease Control and Prevention and the Department of Health and Human Services decided to finish making the seasonal flu vaccine before transitioning to the new vaccine, even as evidence suggested that the new pandemic was going to crowd out the yearly flu. "It is difficult to turn production to new directions based on inertia," says Lone Simonsen, an epidemiologist and nationally recognized flu pandemic expert at George Washington University. But it is just this inertia that makes redirection in vaccine production so crucial.

Last March, as the emerging influenza flu strain took hold in Mexico, infecting thousands before taking hold in the United States, studies showed that this new flu was dominant: It was found in more than 90 percent of the flu cases in Mexico. This new crab grass taking over the lawn was predictable. Since most people (especially the young) had never been exposed to this virus before, there were few barriers to transmission.

Instead of switching immediately to the manufacture of a new pandemic vaccine, the seasonal flu vaccine was completed first. By early fall, 115 million doses of the seasonal flu vaccine were rolled out, and compliance was at an all-time high, thanks to a massive national campaign to promote compliance. Health and Human Services Secretary Kathleen Sebelius said during a Sept. 10 press conference that "getting vaccinated for seasonal flu right now is good advice." Accordingly, more than 60 million rolled up their sleeves and got the vaccine by October, despite the fact that there was no seasonal flu to be found. Lost in the frenzy for flu shots was the fact that the yearly flu season didn't typically peak until late January or February, while pandemics characteristically do not obey the boundaries of traditional winter flu seasons.

Also lost in this well-meaning public-health push was the fact that it was H1N1, not seasonal flu, that continued to spread—with no vaccine to help contain it. Throughout the spring and summer in the United States and around the world, the new flu spread from schools to summer camps. H1N1 was by far the predominant strain during the flu seasons in Australia, New Zealand, and South America, which occur during our summer.

Finally, as production of the yearly flu vaccine was completed in the late summer, preparations began for the H1N1 vaccine, with the CDC announcing in August that it anticipated 45 million doses available by mid-October. Bruce Gellin, head of the National Vaccine Program at HHS, proclaimed that there would be enough vaccine to immunize 160 million people this year.

The fact that these estimates proved to be huge exaggerations—as of this week, we have just around 30 million doses available—was predictable. Part of the problem was that the United States contracted with four manufacturers in Europe and Australia to make millions of doses of the injected vaccine using the antiquated process of inoculating hen eggs with the virus, which can take six to nine months under the best of circumstances. With the H1N1 vaccine, there were also difficulties getting the virus to grow in eggs.

There was another alternative that was not considered here in the States. Baxter Pharmaceuticals' H1N1 vaccine Celvapan utilizes the much speedier process of culturing mammalian (monkey) cells rather than hen eggs. Despite some early concerns that this vaccine could provoke antibodies against our own cells, vaccine trials demonstrated the vaccine to be safe in clinical trials, and it has been approved for use in Europe, where it will be given to millions of people, particularly those with severe egg allergies. But here in the United States, the FDA won't dare fast-track a new, useful vaccine like Celvapan, even in a pandemic, for fear of public criticism.

Going forward, the first step is to re-educate the public about which flu to be concerned about before more people die or are hospitalized unnecessarily. More than 20,000 have been hospitalized so far from H1N1, with close to 4,000 unconfirmed deaths. We must realize that the seasonal flu vaccine is currently useless or, worse, a diversion in the way of getting the H1N1 vaccine. When a 40-year-old asthmatic smoker came to me for the yearly flu shot this week as a result of seeing ads for it, he was upset to find out that I had run out of it. It was hard for me to convince him that he was lucky—I had just received the H1N1 shot. He was worried about its safety, despite my assurances that it was made the same way as all flu shots.

Second, we must put pressure on the FDA to approve the safe and effective Baxter vaccine, and the CDC and HHS should put in an order for millions of additional doses immediately. Simonsen told me that cell-culture flu vaccines are a high priority for the NIH but that the "regulatory world may not be on the same page."

Third, our public health officials should encourage the use of the inhaled Medimmune FluMist vaccine, which is safe for everyone healthy between the ages of 2 and 50. Medimmune has had a very good yield, and millions of more doses can be made in a hurry. Our national vaccine program must be responsive to a pandemic that has now been declared a national emergency. We must be pro-active, and we must be fearless.

Marc Siegel, M.D., is a professor of medicine and medical director of Doctor Radio at New York University’s Langone Medical Center.

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