More flu shot info...

Influenza is a very contagious disease caused only by the influenza virus. Other illnesses often have the same symptoms and are often mistaken for influenza. But, only an illness caused by the influenza virus is truly influenza. This is taken from the Canadian Communicable Disease Report on the 2004-2005 flu season. "Between 22 August, 2004 and 12 March, 2005, a total of 68,849 laboratory tests for influenza were reported, of which 10,319 (14.9%) were positive." Only 14.9% of people who suspected they had the flu were actually infected with the influenza virus. I get people in the clinic everyday telling me "I got a flu shot this year and I'm still sick?!" You're likely not infected with the influenza virus, you likely have a different virus or you have a different strain of the influenza virus that the immunization does not protect you from.

Influenza can lead to other illness such as pneumonia which is especially deadly in the elderly population or people with compromised immune systems, heart or breathing problems. Does that mean that if you're not living with elderly people or anyone who is immunocompromised, that you don't need the flu shot?? The decision is always yours to make but think about the people who you come into contact with everyday. Your elderly neighbor, maybe your co-worker who hasn't confided in you that he has a congenital heart defect, the 8 year old child across the street who was born prematurly and now has asthma... How do you know that you're not giving the virus to people who are at risk?

These are the recommendations that the Canadian Communicable Disease Centre made for the 2005-2006 Influenza Vaccine based on the previous years' statistics:

"The antigenic characteristics of current and emerging influenza virus strains provide the basis for selecting the strains included in each year's vaccine. NACI (National Advisory Committee on Immunization) recommends that the trivalent vaccine for the 2005-2006 season in Canada contain A/New Caledonia/20/99 (H1N1)-like, an A/California/7/2004 (H3N2)-like, and a B/Shanghai/361/2002-like virus strains. Vaccine producers may use antigenically equivalent strains because of their growth properties. The A/New York/55/2004 is antigenically equivalent to the A/California/7/2004 (H3N2) virus strain; B/Jiangsu/10/2003 is antigenically equivalent to Influenza B/Shanghai/361/2002 virus strain. The vaccines to be marketed in Canada for the 2005-2006 flu season contains A/New Caledonia/20/99 (H1N1), A/New York/55/2004 (H3N2), and B/Jiangsu/10/2003 virus antigens. Continual antigenic drift of the influenza virus means that a new vaccine, updated yearly with the most current circulating strains, is needed to protect against new infections."

We find out how correct the CCDC was in estimating the components of the influenza vaccination when the 2005-2006 report is released next fall. It is not just a "guess" as to which strains to include in the vaccine. The vaccination is created based on statistics from past flu seasons. The strains that were prevalent not just last year but years before that as well. Some strains that may have been dormant in the past, come back to haunt us again, and this time they've mutated and become more virulent. That's the problem, strains mutate and change and become more deadly each year. It's impossible to keep up with all the different mutations, it's even more impossible to vaccinate against each one. The best we can do is choose the most prevalent strains, the most deadly, the ones who are the most antigenically equivalent to other strains and protect ourselves against them. We are long overdue for another influenza pandemic and it will come but that is another topic entirely. All I'll say about that is that each year there are more and more protocols and procedures in place to guide health care professionals in identifying and coping with a global influenza outbreak. It is going to make the SARS outbreak look minor.