Risk-benefit looks different in hindsight

Just saw this article from Reuters:  Insight:  Evidence grows for narcolepsy link to GSK swine flu shot.

The crux of the story- the GSK vaccine (used in Europe, not the US) against the 2009-2010 swine flu may be linked to an increase in narcolepsy in young people.

My first reaction, in all honesty, is a fear that anti-vaccination fanatics will latch onto this story and use it as more evidence that vaccines are bad.

My second, I feel sorry for these kids and their families, but I’d take a narcoleptic kid over a dead kid any day.  I feel much worse for the families that lost loved ones to H1N1.

My third reaction, I hope my virologist colleagues can come up with a universal flu vaccine sooner, rather than later, and safety and efficacy studies can be done thoroughly, without a deadly pandemic looming (more so than it looms currently).

How did this happen?  How did this vaccine get approval?  You have to remember the timeline- it’s extremely tight going from identification of a newly emerged flu strain to creating a vaccine against it, studying safety, and ramping up production in time to protect people from it.  This was made even more difficult because H1N1 was identified AFTER manufacturers had already started making the standard seasonal flu vaccine.  If H1N1 had emerged and been identified earlier, it would have been included in the regular seasonal flu shot and this situation may never have arisen (I say “may” because we don’t really know what is happening with the link between the vaccine and narcolepsy).

David Salisbury, the British government’s director of immunization, says “therein lies the risk, and the difficulty, of working in public health” when a viral emergency hits.

“In the event of a severe pandemic, the risk of death is far higher than the risk of narcolepsy,” he told Reuters. “If we spent longer developing and testing the vaccine on very large numbers of people and waited to see whether any of them developed narcolepsy, much of the population might be dead.”

Pandemrix was authorized by European drug regulators using a so-called “mock-up procedure” that allows a vaccine to be authorized ahead of a possible pandemic using another flu strain. In Pandemrix’s case, the substitute was H5N1 bird flu.

When the WHO declared a pandemic, GSK replaced the mock-up’s strain with the pandemic-causing H1N1 strain to form Pandemrix.

GSK says the final H1N1 version was tested in trials involving around 3,600 patients, including children, adolescents, adults and the elderly, before it was rolled out. Source.

Research is ongoing to figure out what the biology is behind this, but there are a number of possibilities- including the adjuvant (not used in the American flu vaccines) as well as genetics and age of those vaccinated.  However, to give you an idea of the numbers:

In total, the GSK shot was given to more than 30 million people in 47 countries during the 2009-2010 H1N1 swine flu pandemic. Because it contains an adjuvant, or booster, it was not used in the United States because drug regulators there are wary of adjuvanted vaccines.

GSK says 795 people across Europe have reported developing narcolepsy since the vaccine’s use began in 2009.

Independent teams of scientists have published peer-reviewed studies from Sweden, Finland and Ireland showing the risk of developing narcolepsy after the 2009-2010 immunization campaign was between seven and 13 times higher for children who had Pandemrix than for their unvaccinated peers.

Being a wealthy country, Sweden was at the front of the queue for pandemic vaccines. It got Pandemrix from GSK almost as soon as it was available, and a nationwide campaign got uptake of the vaccine to 59 percent, meaning around 5 million people got the shot.

The World Health Organization (WHO) says the 2009-2010 pandemic killed 18,500 people, although a study last year said that total might be up to 15 times higher.

While estimates vary, Stiernstedt says Sweden’s mass vaccination saved between 30 and 60 people from swine flu death. Yet since the pandemic ended, more than 200 cases of narcolepsy have been reported in Sweden. Source.

I was pregnant with Mabel when the swine flu epidemic hit.  That year I got two vaccinations- one standard season flu vaccination, and a second specifically for the H1N1.  As a pregnant woman, I was particularly susceptible to flu, and on the priority list of the H1N1 vaccine that was in short supply.

I think what is crucial for the public to understand about this situation is that decisions were being made in an emergency.  There was limited time for safety studies- and it would have taken a very large and time-consuming study to recognize the increased risk of narcolepsy if only 200 out of 5 million people vaccinated developed it.

They say hindsight is 20/20 for a reason.

PANDEMICS ARE EMERGENCIES- Yet the problem with risk-benefit analyses is that they often look radically different when the world is facing a pandemic with the potential to wipe out millions than they do when it has emerged relatively unscathed from one, like H1N1, which turned out to be much milder than first feared. Source.

If H1N1 had been as deadly as we initially feared it would be, we would be rejoicing that all it cost was a few hundred cases of narcolepsy.  However, because we dodged a bullet and H1N1 did not kill as many people as a ‘worst case scenario’ we feel differently.

My heart breaks for these children whose lives were changed, and their families, just as it breaks for those whose loved ones died from H1N1.

For info on how the flu vaccine works, why you need a flu shot every year, and lots of answers to other questions, see the CDC’s “Key Facts about Seasonal Flu Vaccine.”

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Filed under Mother, pregnancy, Scientist

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