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The question: I read a recent news story that said the vaccine used a few years ago to protect against the H1N1 flu virus could have caused narcolepsy in children. Should I be worried about having my children vaccinated this year? Is the flu shot safe?
The answer: It’s true researchers are investigating the possibility that the H1N1 flu shot, or the virus itself, may be linked to an apparent spike in cases of the sleep disorder.
However, you can rest assured that this year’s flu vaccine is very different from the one used to guard against H1N1 in 2009.
“H1N1 was a very special case – it was not the regular flu vaccine,” says Dr. Brian Murray, a sleep specialist at Sunnybrook Health Sciences Centre.
At the time, you may recall influenza experts were concerned the H1N1 virus –commonly known as the swine flu – could lead to an extremely deadly global pandemic. Pharmaceutical companies rushed special vaccines into production to deal with the potential threat.
Like regular seasonal flu shots, the H1N1 vaccines contained antigens, or proteins, that trigger the immune system to produce antibodies to fight the virus. But some of the H1N1 vaccines also included an adjuvant – or booster – to increase the body’s immune response. Using an adjuvant meant the vaccine could be made with fewer antigens. This helped speed up production of the pandemic flu shots, which were in great demand from governments around the world.
About a year later, doctors in Finland were among the first to report an unusual blip in narcolepsy cases especially among children and teens. Only one type of H1N1 vaccine had been used in Finland – Pandemrix which contained an adjuvant. In other countries where adjuvants were used – notably in Europe and China – doctors began to make similar observations.
Still, the actual number of cases remains relatively small compared to the millions of people who received the vaccine worldwide.
According to a report from the National Institute for Health and Welfare of Finland, the increased risk corresponds to about 6 extra cases of narcolepsy per 100,000 children vaccinated and one extra case per 100,000 adults who got the shot.
Narcolepsy is a rather uncommon neurodegenerative condition. It normally occurs among 25 to 50 out of every 100,000 people in the general population and rarely affects children.
Patients suffer from profound daytime drowsiness says Dr. Murray who is also an associate professor at the University of Toronto.
They can also experience a related problem called cataplexy – the sudden loss of muscle tone, particularly with an emotional trigger. “If you tell them a joke, they can fall down,” says Dr. Murray. “It sounds very bizarre, but there are pathways in the brain that suggest why that happens.”
Narcolepsy results from the loss of a brain chemical called orexin (also known as hypocretin) that plays a key role in regulating sleep-wake cycles.
Dr. Murray points out that the human mind typically exists in three different states – awake, REM sleep and slow-wave sleep.
“Orexin is a kind of psychic glue that holds you in one state or another and it is when you start to drift in between states there is a problem,” he explains. “You start to fall asleep while you are awake. Or, you lose muscle tone which is a normal feature of REM sleep, but it is abnormal for the waking state.”
Dr. Murray says it’s possible a component of the H1N1 vaccine leads the immune system to destroy orexin-producing cells in some people who are genetically predisposed to the disorder. But he cautioned a lot more work is needed to confirm such a theory.
The Brighton Collaboration, a vaccine-safety group sponsored by the World Health Organization and the U.S. Centers for Disease Control, is providing seed money to researchers who are investigating the matter.
With some of that funding Dr. Murray and Dr. Jeff Kwong, an epidemiologist with the Institute of Clinical Evaluative Sciences at Sunnybrook, are conducting a study to see if the vaccine is linked to a rise of narcolepsy cases in Ontario.
“It’s a gargantuan task,” says Dr. Murray. “We are trying to identify every patient who developed narcolepsy in Ontario, and then go through all the paper records of immunization status to figure out whether they got the vaccine or not.”
In Canada, the H1N1 vaccine was called Arepanrix. It was similar to Pandemrix used in Europe and included an adjuvant. (Some batches of non-adjuvanted vaccine were produced for pregnant women.)
The findings from the Ontario research, and other studies, could have important implications for the future use of adjuvants, said Dr. Murray.
For this flu season, though, adjuvants are not an issue. The vaccine doesn’t contain them. “Don’t let this prevent you from getting the regular flu vaccine,” says Dr. Murray. “This is not the same kind of scenario.”
Paul Taylor is Sunnybrook’s Patient Navigation Advisor. His column Personal Health Navigator provides advice and answers questions from patients and their families, relying heavily on medical and health experts. His blog is reprinted on healthydebate.ca with the kind permission of Sunnybrook Health Sciences Centre. Email your questions to AskPaul@sunnybrook.ca
The comments section is closed.
I’m from Ontario and became sick directly after the H1N1 shot in 2009 with moderate head, neck, arm pain and sever gatrointestanial symptoms. I recovered for a short period of time but then gradually within a year symptoms kept surfacing until I now have chronic pain along with fatigue, insomnia, IBS and cognitive memory involvement. I was diagnosed by Rhematology with fibromyalgia which is neurotransmission. Have any links to CFS/ME Fibromyalgia been associated with this vaccination along with norcolepcy? The sleep disorder sounds very familiar to what I experienxe.
Here’s my question to u…… I was 34 last year when I received a flu vaccine jan. 25, 2013. For school purposes. Mid February started showing signs and symptoms of narcolepsy and cataplexy.. I was told by my family doctor I received the 2012 fall flu vaccine in January 2013. Isn’t the same ingredients in that vaccine that was also in the H1N1 vaccine? I’ve been doing research on my on and came across that it was…I’m 35 now and am seeing Dr. Colin Shapiro for all this.. I’ve been healthy as a horse till I had that flu shot. Has there been anymore cases like mine come up recently? Any help or more information as I am currently doing a report on narcolepsy and how it affects the nervous system for my Anatomy and Physiology class. Also to educate my teachers and what they have seen or experienced while I have been in there class.
Hi Lisa, I am In the uk. My 8 year old son had the seasonal flu shot October 2012 and started with symptoms January 2013. His vaccine contained…. A/California/7/2009 (H1N1)pdm09-derived strain used
(NYMC X-179A)
I am also looking into the fact this seems to be the same strain as the 2009.
mummymeof4@hotmail.co.uk
“However, you can rest assured that this year’s flu vaccine is very different”
So roll up your sleeves until we find something wrong with this year’s flu vaccine.
Hi Denise:
The H1N1 shot should not have an additional negative effect on people who already had narcolepsy.
You may recall that narcolepsy results from the loss of a brain chemical called orexin (also known as hypocretin) that plays a key role in regulating sleep-wake cycles.
Once the orexin-producing cells are lost, with the initial onset of narcolepsy “there is no further chance for damage” says Dr. Brian Murray, a sleep specialist at Sunnybrook Health Sciences Centre.
Paul Taylor
Thank you Paul for your prompt response.
Denise
My concern is what impact has the `H1N1 vaccine had on those of of us who already had Narcolepsy ( in my case for the past 16 years). Has there been any studies done on whether the vaccine could havw aggravated the exisiting condition?
Hi Anna:
Thank you for your email.
Dr. Brian Murray’s study will be relying on provincial data bases to assess the possible link between H1N1flu shot and narcolepsy.
So you don’t need to notify him directly about your daughter’s case.
You also had questions about your daughter’s medical care. Where to go for answers depends on your daughter’s age. If she is under 18, Dr. Murray suggests contacting the Hospital for Sick Children in Toronto.
“If she is over 18, I would be happy to see her clinically if there are outstanding concerns,” says Dr. Murray.
Your family doctor would need to make a referral to Dr. Murray.
I wish your daughter the best for her recovery.
Paul
My daughter received the h1n1 vaccine in Ontario.
It took several years but she has now been definitively diagnosed with narcolepsy.
She is currently being treated with medication but we wonder what next?
Should her diagnosis be reported to someone? Can this link be confirmed on an individual basis?
Any advice would bee greatly appreciated.
Thank you for the information provided in your article.