Is the H1N1 Swine Flu Vaccine Safe?
H1N1 Swine Flu Vaccine Safety: Hype, Myths, and Facts
Does the H1N1 swine flu vaccine contain thimerosal?
The 2009 H1N1 swine flu vaccine comes in three basic types: the FluMist nasal spray, single-syringe shots, and
Only the multi-shot vials contain thimerosal, a preservative that prevents
bacterial contamination of the vial. Before thimerosal was added to vaccines,
there were occasional vaccine injuries due to contamination.
Extensive study shows that there are no more adverse events in children or
adults who receive thimerosal-containing vaccines than in those who do not.
But thimerosal contains a form of mercury. It's ethyl mercury, which is
likely not as toxic as some other forms. Even so, nobody argues that mercury is
good for your body. People who want to avoid thimerosal-containing flu vaccines
must get the FluMist vaccine or the single-syringe shots.
Most people should have this choice. But single-syringe vaccines may not be
available for every person in every location during every week of the
The 1976 swine flu vaccine wasn't safe. Why should I trust this one?
The 1976 swine flu vaccine was linked to safety issues. Neal Halsey, MD,
director of the Institute for Vaccine Safety at the Johns Hopkins Bloomberg
School of Public Health, was at the CDC in those days.
"We did identify an increased risk of GBS [Guillain-Barre syndrome] in
the six weeks following immunization," Halsey tells WebMD. "What is not known
at this time is exactly why that vaccine was associated with that increased
No flu vaccine since then has been linked to this risk. Halsey thinks there
is the potential for the H1N1 flu vaccine to carry a risk of causing one case
of GBS per million people vaccinated.
"The theoretical risk of that rare complication has to be balanced against
the severity of the H1N1 flu," he says. "There already have been a lot of
deaths, many in otherwise healthy, normal children. There is always a real risk
from the flu, and a theoretical risk from the vaccines."
In 1976, the risk from flu was theoretical, too. Despite a scary and fatal
outbreak of an H1N1 swine flu at a military base, the virus never spread.
The 1976 H1N1 swine flu was a very different virus from the 2009 H1N1 swine
flu, which combines elements from flu viruses that evolved in birds, humans,
and pigs. And unlike the 1976 virus, the 2009 bug is causing a very real
Do we really know what drugmakers are putting in the swine flu vaccine?
Vaccine labels are not easy to read. But they are made public by the FDA and
other sources. If you want to know exactly what's in each kind of 2009 H1N1
swine flu vaccine, read the label. You can find all the labels here: http://www.vaccinesafety.edu/package_inserts.htm.