Is the flu shot right for you?
To get the shot or not?
That's the question millions of Canadians ask each fall as flu season arrives. It's a worthy query, although answering it with an unequivocal yes or no would be to ignore the realities of the virus or the ways humans respond to it.
On the surface, getting the shot seems a no-brainer. About 1,500 Canadians die annually from the flu, a strain of which killed an estimated 20 to 40 million worldwide in 1918. While the vast majority of people who get the flu never come close to being critically ill let alone dying, they can endure a week of fever, muscle pains, exhaustion and other nasties. Who needs that?
But nothing is straightforward when it comes to influenza.
The making of a vaccine
That's because the flu constantly reinvents itself. Every spring the World Health Organization predicts the three most virulent strains for the coming season and that determines what goes into the vaccine.
“You have to have those three components in your vaccine,” says Earl Brown, a virologist at the University of Ottawa. “You know that those are going to be the players, but you don't know which are going to be the big players.”
How a shot can protect you
The vaccine aims to trick the body into thinking it has been exposed to those three strains, thereby triggering production of antibodies. Healthy individuals who get immunized have 70 to 90 per cent protection. Immunity lasts up to a year. Some may have mild soreness and swelling at the injection site and a few experience fever and muscle aches shortly after vaccination.
“That's your defense system mobilizing and it's kicking you at the same time,” says Brown.
Because the vaccine contains dead viruses, it cannot cause the flu. But neither can it protect against other strains of influenza or non-influenza agents. Health Canada reports that of the more than 48,000 cases of influenza-like-illnesses examined and tested during the 2001-2002 flu season, 13 per cent were either influenza A or B and the rest - 87 per cent - involved other pathogens.
Who should and shouldn't get the shot
Still, Vancouver Coastal Health Authority chief medical health officer Dr. John Blatherwick says the shot is a must for the elderly and those with chronic health conditions. What's more, he adds, “for a health care worker not to get this vaccine and not protect the people they care for, is absolutely unacceptable.”
Those who should not get the flu shot are: anyone allergic to eggs (the virus is grown in chicken eggs), anyone who has had a severe reaction to a previous flu vaccine, and children under six months.
Testimonial for the flu shot
Gilles Presseau is a 44 year-old Ottawa social worker and flu shot devotee. Before he chose to get immunized, the flu caused him to miss a week of work at a time.
“The first year I tried it, I still got the flu but it only lasted 24 hours . . . which was wonderful,” Presseau says.
Yet, he points out, hardly anyone else in his office gets the shot. Despite a massive public health campaign, many Canadians decline. The flu shot is not without its skeptics.
The other side of the story
Dr. Jim Wright is a University of B.C. professor, physician, pharmacist and head of a drug evaluation program called Therapeutics Initiative. He used to get the flu shot but stopped after finding little proof of its purported powers.
“I was shocked at how weak the evidence is that it is beneficial,” Wright says. “I think the answer is we really don't know how much benefit there is.”
What's more, says Wright, the vaccine, like any medication, can come with side effects.
Saddled with side effects
Janaia McQuaig is a 30-year-old Calgary mother of three who says she suffered adverse effects from the influenza vaccine. In October 1999 McQuaig, an asthmatic, got the second flu shot of her life.
“I was a believer in vaccinations,” she says.
The following day, McQuaig woke with bloodshot eyes, vomiting and wheezing. “My asthma was completely out of control.”
Figures and factors
Adverse reactions of the sort McQuaig experienced are not common but they do happen. In the 2000 – 2001 flu season, almost 2,450 people reported having adverse effects to the flu shot. Many suffered red eyes and wheezing-like respiratory symptoms known as oculo-respiratory syndrome (ORS). Vancouver epidemiologist Danuta Skowronski of the B.C. Centre for Disease Control studied the occurrence extensively. Skowronski says the large number of adverse reactions were linked to a flaw in the vaccine's production process.
Weighing your options
“Overall, if you balance the risk of that side-effect with the risk of influenza, the vaccine is still a clear winner,” Skowronski says. “But even mild adverse effects can be disturbing especially if you're targeting more young healthy people in the population, which we are.”
Brown agrees. While people shouldn't lose sight of what infections like influenza can do, he says, that doesn't mean “there's no problem with vaccines.”
Says Blatherwick, “There are adverse reactions. . .but in this province we do close to a million shots a year. You're going to have people who are going to have something in association with this vaccine. Yet it's been proven to be one of the safest vaccines around.”
