Did the 2009 flu vaccine give people narcolepsy?

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Experts blame spike in sleep disorder on the shot – which the US has stockpiled for the next swine flu outbreak

  • Swine flu, or the H1N1 strain of the virus, swept the globe in 2009
  • In Europe, scientists found a surge in cases of narcolepsy afterwards 
  • They believe a particular flu shot may have triggered an autoimmune problem that causes the disease
  • Narcolepsy cases did not increase significantly in the US where the problematic ingredient was not used in the shot
  • But now the US stockpiles the immune response-boosting ingredient in case of another H1N1 pandemic 

By Natalie Rahhal

An emergency stock of powerful flu vaccines may cause narcolepsy, and scientists are still trying to work out why.

In 2009, the H1N1 or swine flu pandemic swept the globe, killing an estimated 284,000 people.

In many countries in Europe, people were given an adjuvant vaccine against the illness, meaning it contained ingredients intended to ramp up the body’s immune responses to the flu exposure.

Many people still got the flu, and scientists noticed a spike in cases of the rare sleep disorder, narcolepsy, following the pandemic.

Now, researchers believe the shot may have triggered an autoimmune disease that in turn caused narcolepsy and are attempting to prove it before another swine flu pandemic heads for the US and we need to dip into the adjuvant stockpile.

Though the link couldn’t be established int he US, where the adjuvant shot wasn’t used in 2009, experts told Stat that we should still be wary of its neurological effects.

For healthy adults, the flu does not typically pose a serious threat (although this most recent season served as a reminder that no one is truly safe from a powerful strain).

Young children, on the other hand, are particularly susceptible to the illness. The younger they are, the less their immune systems have been exposed to and the weaker they are.

The Centers for Disease Control and Prevention (CDC) caution that children under five can easily develop serious and even life-threatening complications of the flu and are more likely to wind up hospitalized.

For that reason, the agency urges parents to make sure that all children over six months old get a flu vaccine each year.

These families are far more likely to be concerned that their child stays safe from the flu than they are about their son or daughter suddenly developing narcolepsy.

But after the 2009 pandemic, European families now have to think twice about the flu shot their kids get.

Following the swine flu outbreak, an increase in cases of narcolepsy was reported first in Finland, then in the UK and several other nations.

The spike was traced back to one particular vaccine, called Pandemrix, which is made by the pharmaceutical company GlaxoSmithKline in Europe.

Formulas for flu shots vary and Pandemrix belongs to the adjuvant category of vaccines.

Adjuvants are ingredients added to vaccinations to give them a power boost. Flu shots introduce the body to the virus and adjuvants encourage a stronger immune response to this initial exposure, which should help the body fight off the flu itself.

But what is good for the immune system’s response to flu may actually make the same immune system attack itself, leading to narcolepsy.

Narcolepsy is an autoimmune disorder, meaning it results from the body’s attacks on its own brain cells. It causes the immune system to target cells that produce a chemical called hypocretin.

This chemical keeps us alert and holds us back from slipping into REM sleep at the wrong times.

Without it, narcolepsy sufferers don’t follow normal patterns of waking and sleeping, and may instead find themselves unbearably tired at odd times and seem to fall asleep suddenly, even in the middle of a task.

The rare disorder, which only affects one in every 2,000 people in the US, starts early in life for most, but can come on at any point in adolescence or adulthood.

Scientists remain unsure exactly how the adjuvant vaccines might trigger the narcoleptic autoimmune response, but the link established strongly enough in Finland and the UK for the CDC to post a notice about it.

Most people who got the vaccine in 2009 didn’t get narcolepsy, so scientists think the shot might be just one of several hits to the immune system that can cause it to break down and lead to narcolepsy.

‘So now our hypothesis is that the flu in some circumstances can produce an immune reaction that turns wrong, and instead of clearing the flu, is also attacking the hypocretin neurons. And then you have narcolepsy,’ Stanford University sleep disorder expert Dr Emmanuel Mignot told Stat.

In 2014, the CDC published their own investigation into whether or not there was a similar link in the US, but concluded there was not. Two years later, another study was unable to find strong enough evidence to to link the two in the US, but many remain wary of the adjuvant shot.

For one, the US did not use the adjuvant shot. In fact, H1N1 was new to the country, and the distributed seasonal vaccine did not even protect against the powerful strain of the virus.

But now, the US does stockpile the adjuvant in question, AS103, so when pandemic levels of H1N1 viruses return – and experts say it is a matter of ‘when’ not ‘if’ – it is entirely possible that a spike in narcolepsy cases could follow.

This article (Did the 2009 flu vaccine give some people narcolepsy?) was originally published on Daily Mail and syndicated by The Event Chronicle

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