Re Flu Vaccine Requires Further Thought (the News, October 15):
I am grateful that Barbara Drury took time to voice her concerns about the influenza vaccine as this gives me the opportunity to correct some misconceptions about this vaccine.
Is the flu such a big deal? For a young healthy person, influenza generally means a few days in bed or away from work or school. But for those who are more vulnerable, it can be devastating Ã even deadly. There is no other infectious disease threat in Canada that comes with such regularity and with such a toll on the public as influenza.
For the purposes of this letter I will paraphrase Drury’s comments in order to explain each concept in sequence.
1) Immunization weakens the body’s ability to recognize and resist viruses, making us more susceptible to disease.
False. There is no evidence whatsoever that any vaccine interferes with our intrinsic ability to resist disease. On the contrary, vaccines assist our immune systems in recognizing pathogens. The “flip side” of not vaccinating is that even though most will recover, some individuals will be overwhelmed by the infection and can get complications or even die from the infection.
2) Agents that are used in the vaccines (such as squalene, thimerosal, etc.) may have dire consequences for some people.
False. Additives to vaccines are present for a variety of purposes, whether as immune boosters (or adjuvants), preservatives, stabilizers or to prevent contamination.
Squalene, which is a shark-oil derivative, was used in last year’s adjuvanted H1N1 vaccine. Using an adjuvant or immune booster increased the effectiveness of the vaccine and allowed more vaccine to be available. Although adjuvants are used in other vaccines, such as HPV vaccine, there is no adjuvant in the seasonal influenza vaccine. Initial clinical trials showed squalene to be extremely safe. Canada’s vaccine surveillance system confirmed how safe this product was during the administration of millions of doses of H1N1 vaccine last year.
Thimerosal is used as a preservative and as an antiseptic to prevent contamination of the flu vaccine vials. It is present in extremely small quantities, has been studied extensively, and has not been linked to any adverse effects. In recognition that there is significant public discomfort with this product, thimerosal-free influenza vaccine vials are being researched and are expected to be available within a few years.
3) Science is divided on how well flu vaccines work or how necessary they are.
Somewhat true but mostly false. The debate is not between opposite views as much as between differing interpretations of how well the vaccine works, and therefore how useful it really is. What medical scientists do agree upon is that next to safe drinking water and sanitation, immunization is the most effective way to protect people from communicable disease and its consequences.
As often happens in scientific inquiry, there is debate over numbers: how effective is influenza vaccine in preventing deaths and complications? Variable conclusions are almost inevitable due to the types of observational studies that are required to answer these questions. Such studies are hard to rid of confounding factors that can explain some of the conclusions.
In addition, there is substantial variation from year to year in how well the vaccine matches the circulating influenza viral strains. Add to this that the flu vaccine works better in some age groups than in others: the strongest response to the vaccine will be in healthy young people, whereas the weakest uptake tends to be in those who are most prone to the complications. Overall, the vaccine’s effectiveness in preventing influenza varies from 40 to 90 per cent depending on the match. Thus in any one year, at least half, if not the vast majority of the people vaccinated will be protected from the flu.
4) Canada, unlike Europe, New Zealand and Australia, accepts “hook, line and sinker” what the pharmaceutical companies are advocating.
False. New Zealand and Australia and many, if not most, European countries have publicly funded influenza vaccine programs that target similar groups to those identified in Canada as being especially at risk.
The pharmaceutical companies that manufacture vaccines have products to sell, often in a competitive environment. It is our job in public health to examine new products, make sure that the studies are adequate in number and design, compare new vaccines to our needs and priorities, involve expert groups in evaluation, ensure products go through a rigorous regulatory process, and then decide whether publicly funding such products are in the best public interest.
What’s best for Yukoners? I believe that the current influenza vaccination program is the best option for us, protecting our population from influenza-associated complications and death. As always, Yukoners can exercise their choice to opt out, and that is a choice that I must respect.
The best medical evidence along with expert advice tells us that there would be a substantial risk to the health of Yukoners, especially to our seniors, our very young, and those with chronic medical conditions, by not offering the vaccine as a public service.
Brendan E. Hanley MD CCFP(EM) MPH
Chief Medical Officer of Health, Yukon