Friday, August 29, 2014

Low rate of adverse reactions to vaccines

TORONTO—A new Ontario report on vaccine safety shows the rate of adverse events reported after vaccinations in the province is low.
The report says there were 56 serious vaccine-related adverse events reported in 2012—a year when 7.8 million vaccinations were distributed in the province.

That is 7.2 serious events for every one million vaccinations.
Serious reactions were things like convulsions, seizures, and anaphylaxis—an allergic reaction that can range from an itchy rash and hives to difficulty breathing and, in severe cases, shock.
The report said none of the serious reactions reported in 2012 were fatal.
The report is the first of what is expected to be an annual assessment of vaccine safety in the province published by Public Health Ontario.
The agency’s director of immunization and vaccine preventable diseases, Dr. Shelley Deeks, said the goal is to be transparent about vaccines in a climate where there are many questions and misperceptions about the products.
“I feel we have a responsibility to provide this information back [to the public] . . . and probably do a little bit of a better job of communicating how safe our vaccines are,” she noted.
“But also communicating that they’re not perfect, and that no drug or biologic product is perfect.”
The report covers vaccinations given at all ages.
And it makes clear that the adverse events reported may not have been caused by vaccines.
A difficulty that arises in adverse event reporting is that something that happens after someone took a drug or got a vaccination may have been unrelated to the medical intervention—but there often is no way to tell.
So the report says the events are “temporally associated”—linked in time—but may not have been caused by vaccinations.
There were 631 adverse events reported after vaccinations, but the bulk of them fell into the mild category.
They included things like sore arms (252), rashes (137), and fever (47).
That leads to a rate of 4.7 adverse events for every 100,000 vaccines distributed in the province, which is well below the national average of 9.4 per 100,000 vaccinations.

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