Photo Credit – CDC PHIL
# 5928
We’ve another study – published yesterday in The Lancet- on the safety of the 2009 pandemic vaccine that looked specifically at the development of Guillain Barre Syndrome among pediatric vaccine recipients in the UK.
Guillain-Barre Syndrome (GBS) is a neurological disorder that gained notoriety in 1976 after it was linked to an emergency flu vaccine that was rolled out in anticipation of a `swine flu’ pandemic.
As it turned out, the feared pandemic never came.
But before the campaign was abandoned - among the 40 million people who were vaccinated - around 500 people developed GBS and 25 died.
While not all of those cases were likely caused by the vaccine, the incidence of Guillian-Barre Syndrome was around 1 in every 100,000 vaccinations. Or five times the expected background rate of this disease.
I was a young paramedic at the time, and chronicled my part in that bit of influenza history some time ago in Deja Flu, All Over Again.
In the more than 3 decades since that fiasco, there has been little or no evidence of flu shots causing Guillain-Barre Syndrome.
Still, memories of 1976 linger on, and anti-vaccine activists were only too happy to recall the unfortunate events of that year as they repeatedly warned that the `2009 swine flu vaccine was deadlier than the flu’.
Of course, the evidence clearly showed otherwise.
Surveillance and reporting systems have not found any unusual pattern of deaths in the United States attributable to the pandemic vaccine, and the oft predicted spike in Guillain-Barré syndrome (GBS) never occurred (see CIDRAP VAERS study finds H1N1 vaccine safety similar to seasonal vaccines').
In fact, the VAERS report cited above found 0 deaths they could link to the pandemic Vaccine. Meanwhile, during the same period the CDC estimated that at least 12,000 (mostly younger) Americans died from the flu.
The CDC, along with many other public health agencies, have allowed that the flu vaccine might carry with it a very low risk of developing GBS. But most years the incidence is so low (perhaps 1 in 500,000 or 1 in a million) as to be nearly impossible to measure.
This from the CDC’s Guillain-Barré syndrome (GBS) Q&A page.
What causes GBS?
Many things can cause GBS; about two-thirds of people who develop GBS symptoms do so several days or weeks after they have been sick with diarrhea or a respiratory illness. Infection with the bacterium Campylobacter jejuni is one of the most common risk factors for GBS.
People also can develop GBS after having the flu or other infections (such as cytomegalovirus and Epstein Barr virus). On very rare occasions, they may develop GBS in the days or weeks after getting a vaccination.
Recent studies have shown that you are many times more likely to develop GBS in the weeks following an influenza infection, than you are after getting the flu vaccine (see Lancet: The Influenza - Guillain Barré Syndrome Connection).
The irony here is, that the flu vaccine may turn out to be the best protection against the adverse vaccine effect that people seem to fear the most.
Adding a bit more weight to that argument, we’ve a letter published yesterday in The Lancet that looked at children who developed Guillain-Barré syndrome or Fisher's syndrome between September, 2009, and Aug 31, 2010.
doi:10.1016/S0140-6736(11)61665-6
Guillain-Barré syndrome and H1N1 influenza vaccine in UK children
Christopher Verity, Lesley Stellitano, Anne Marie Winstone, Nick Andrews , Julia Stowe , Elizabeth Miller
During the 12 months of surveillance, 55 children in the UK were diagnosed with GBS or Fisher’s syndrome.
Of those, only 3 had received the pandemic flu shot, and of those, only 1 had received the shot within 6 weeks of developing neurological symptoms – a time frame that could suggest a causal relationship to the shot.
Among those same 55 children, 49 showed laboratory or clinical evidence of infection in the 90 days prior to developing symptoms.
- 22 had respiratory infections
- 13 had gastroenteritis
- 7 had H1N1 influenza (5 laboratory-confirmed)
- 2 had seasonal influenza (1 laboratory confirmed)
- 2 had Epstein-Barr virus
- 1 had chickenpox
- and 2 had unexplained fevers
Which matches pretty close to the CDC GBS FAQ above that states: about two-thirds of people who develop GBS symptoms do so several days or weeks after they have been sick with diarrhea or a respiratory illness.
The authors conclude by stating:
The peak in the number of children with Guillain-Barré syndrome or Fisher's syndrome shortly after the peak of the second wave of H1N1 infection in November, 2009, might reflect this causal association (figure).
Given the proven effectiveness of pandemic influenza vaccine used in UK children, the vaccination programme might have had an overall protective effect against Guillain-Barré syndrome.
Another UK study I highlighted last July (see BMJ: No Substantial Link Between Flu Vaccines And Guillain-Barre Syndrome), similarly found:
“Adjuvanted pandemic influenza A (H1N1) 2009 vaccines did not increase the risk of Guillain-Barré syndrome substantially, if at all.”
For more reassuring research on the safety profile of modern flu vaccines, you may wish to revisit the following blogs:
Harvard Study Reaffirms Safety Of Flu Vaccine
MJA: Safety Of Flu Shot In Young Children
NEJM: Study On China’s H1N1 Vaccine Safety
Lancet: Immunogenicity and safety Of Adjuvanted Flu Vaccines
While no vaccine (or drug) can be said to be 100% safe – and rare but sometimes serious adverse effects have been reported - the preponderance of evidence continues to support the scientific consensus that flu vaccines are very safe and most years, reasonably effective.
