I seem to be having a lot of people showing up at my door-step asking for a flu shot, just in case that avian thing shows up. This theoretical concept of bird flu resulting in a human pandemic seems to have a lot of people worried. It is interesting to see that fear and misinformation are once again driving this year's immunization campaign. There are two things that patients are surprised to learn. Firstly, this year's shot does "diddly" for people who think that sneezing birds are going to give them the flu. The Avian flu poses no substantial danger to the human race at this time. Your money would be better spent wagering on the Leafs to win the Stanley Cup. Secondly, anyone who pays taxes has already pre-paid for the flu shots, so you might as well drop in and collect what is owing to you.
After a mild flu season last year, Influenza A activity has yet to make its presence felt in Ontario. Influenza is a group of closely related viruses which produce sudden and severe respiratory illness. We loosely divide flu into Types A, B and C with the A group being more troublesome. Viruses are very small particles of genetic material within protein coats that are microbiological dwarfs compared to monstrous bacteria. The influenza virus exists by attaching to and invading human cells. This is essential for reproduction and survival. The A group, which natural host has always been birds, is more likely to spontaneously mutate and produce a new strain as a way to get around immune systems and survive. We refer to subtypes by using the geographical location of first isolation along with year of discovery, coupled with short-forms for two different proteins found on the coat. Hence names like A/Wyoming/3/2003 (H3N2), A/NewCaledonia/20/99 (H1N1), or B/Jiangso/10/2003. It is possible to be infected by several different strains through the course of a season. Last year, the influenza season had a "light" impact on our health care system. Tens of thousands of Canadians were infected with over 800 different species of influenza. Symptoms appeared suddenly and quickly: Fevers, chills, muscle aches, stomach upset, cough, mild sore throat and fatigue, to name a few. It has been described like being beat up. Thousands succumbed to it mostly because they were ill to begin with.
We are fortunate in having the distinction of being one of the few places in North America where a free mass vaccination program is in effect. It is not cheap and does have some problems with distribution, duplication, delays and record keeping. Public Health distributes the vaccine to physicians and runs parallel clinics in public places. I would prefer to see these publicly run clinics targeting high risk groups by being run in nursing homes and hospital out-patient areas rather than local shopping malls. If you use a public clinic to get your shot, ensure that you obtain documentation of which vaccine you received, the lot number and expiry date. The only way this information gets into your medical record is if you put it there. I advocate getting your flu shot through your own doctor.
Let's consider a few pointers. There are different manufacturers and hence several vaccines on the market. Most of the vaccines in Ontario are of the split-virion type. This year's flu-shot will protect against three nasty subtypes of virus (A/New Caledonia/20/99-H1N1, A/New York/55/2004- H3N2, and B/Jiangsu/10/2003). This contrasts with the avian strain which is a H5N1 subtype. The included strains are selected from data compiled by the World Health Organization on a best-guess basis. Vaccine makers choose a virus which resembles the wild virus, but grows easily in egg culture. It is then inactivated with formaldehyde and ultra-violet light. This is followed by chemical disruption and filtration to purify the components. There is no live virus in flu-shots anymore. Vaccination introduces the proteins found on the virus to our immune system. It is these proteins or antigens that our immune system uses to recognize foreign invaders. The idea is to get your immune system to respond, so that the feeling of a mild impending cold afterwards is normal. It is a safe effective method to prevent a few severe illnesses.
Flu shots do not protect you from all influenza, but are effective against three severe forms. There are other alternatives which are less effective, but merit mention only because the only certainty that I can truly offer is that influenza activity in our region is a guarantee. Some of my healthy and fit patients have chosen to temporarily defer the flu shot and monitor the Health Canada Flu Watch Program. What card-counters are to black-jack, these people are to flu mutation. They monitor outbreak activity along with sero-types and take their shots when they are certain the strains contained in the shot are imminent in their community. One problem with this is the delay between outbreak and diagnosis. So how do you know? One tidbit from the trenches suggests that when 10 percent of your employees or students are down with influenza-like symptoms, there is a good chance that a major outbreak is occurring. I only hope that vaccine is still available when they finally decide they need it. Others have taken the attitude of running. In this strategy, you seclude yourself from the air-borne sources in your community by staying indoors or moving to a non-infested location at the first sign of severe disease activity. This strategy is neither practical nor economical, but does work for some. When an outbreak occurs in a nursing home and the culprit flu virus is not covered by the shot, and then out comes a hardy dose of an older medication called amantidine for all the residents. It helps prevent invasion and is still effective for many subtypes of the flu. Stockpiling of drugs like Tamiflu is not a prevention method, nor is it a sure-shot cure. It simply helps reduce the duration of illness in some cases.
Most fit and healthy adult Canadians have successfully fought off more than one bout of influenza in their lives. Despite all precautions and research, we have no potential to eliminate the influenza virus from our lives anytime soon. In parting, my wish for you is that no matter which preventative strategy you choose, I sincerely hope that your next infection is a minor one.
● Current Flu Situation in the United States.
● Flu Shot Clinics in Canada.