(RxWiki News) All types of preventive medicine offer benefits and risks, and vaccines are no exception. But often, the risks related to getting a disease may be greater than the risks of the vaccine.
A recent study found that the risk for a specific nerve disorder was greater for people who become sick with the flu than those who received the flu shot.
There was a tiny increased risk for Guillain-Barré syndrome in individuals who received the flu shot. But the risk for this nerve condition among those who became sick with the flu was much greater.
Patients should be aware of both risks, the authors said, in making their decisions about whether to get the flu shot.
"Ask your doctor about the flu vaccine."
This study, led by Jeffrey C. Kwong, MD, of the Institute for Clinical Evaluative Sciences and the Dalla Lana School of Public Health at the University of Toronto in Canada, looked at the risk of Guillain-Barré syndrome after the flu shot and after being sick with the flu.
Guillain-Barré syndrome is an autoimmune disorder in which the immune system attacks the body's nervous system.
The researchers used a database of health care records in Ontario, Canada from 1993 through 2011 for their data. They identified all the individuals who had received the flu vaccine and all the individuals who had been seen for the flu, based on doctor billing records.
Then they compared this information to those patients who were hospitalized for Guillain-Barré syndrome during the same time.
A total of 2,831 patients were admitted to the hospital for Guillain-Barré syndrome during the study period. Of these patients, 330 had received the flu vaccine and 109 had been seen for the flu within the previous 10 months.
The researchers found that the risk for being hospitalized for Guillain-Barré syndrome within six weeks of getting the flu shot was 1.5 times higher than among those who did not get the flu shot.
However, the risk of hospitalization for Guillain-Barré syndrome was significantly higher among those who became ill with the flu.
The risk for Guillain-Barré syndrome was almost 16 times higher for patients who were sick with the flu than those who did not get the flu.
Put another way, approximately one person for every one million flu vaccines may be admitted to the hospital for Guillain-Barré syndrome.
Meanwhile, 17 people will be admitted to the hospital for Guillain-Barré syndrome for every one million who get the flu.
"The small risk of Guillain-Barré syndrome associated with influenza vaccines of roughly one admission per million vaccinations should be placed in the context of the risk of Guillain-Barré syndrome associated with influenza infection," the authors wrote.
"Patients considering immunization should be fully informed of the risks of Guillain-Barré syndrome from both influenza vaccines and influenza illness, as well as the more substantial direct and indirect benefits from immunization in terms of preventing morbidity and mortality," they wrote.
This study was published in the September issue of The Lancet Infectious Diseases. The research was funded by the Canadian Institutes of Health Research.
One author has received research funding from Sanofi Pasteur and GlaxoSmithKline and has received funds for speaking or advisory positions from Sanofi Pasteur, GlaxoSmithKline and Novartis Pharmaceuticals. No other authors reported potential conflicts of interest.