Influenza Activity - Update
Updated: January 7, 2004
The Public Health Agency of Canada continues to monitor global influenza activity. Significant
influenza activities are currently occurring in Europe, Africa and North
America. So far this year, most influenza outbreaks have been associated
with the influenza A (H3N2) virus with most being antigenically characterized
as A/Fujian/411/2002-like, with the rest being A/Panama/2007/99-like.
Source: The World Health Organization 
It is not possible to absolutely predict in advance what type of flu season
we will have. Influenza viruses are changing all the time. The effectiveness
of a vaccine depends, in part, on the match between vaccine strains and
circulating viruses. In Canada, the influenza vaccine is formulated annually
based on the influenza strains predicted to arrive in the northern hemispere
in the coming season.This year's vaccine contains an A/Panama/ 2007/99 (H3N2)-like,
an A/New Caledonia/20/99 (H1N1)-like, and either B/Hong Kong/330/2001-like
or B/Shangdong/7/97-like antigen.
While the vaccine available in Canada this year covers the A/Panama/2003/99-like
strain, is does not cover the A/Fujian/411/2002-like strain currently circulating
in certain areas. However, laboratory studies indicate that the current
vaccine should still provide some cross-protection against A Fujian strain.
Travellers are reminded that influenza outbreaks may occur anywhere in
the world at any time. The influenza season usually runs from November to
March in the northern hemisphere. In temperate regions of the Southern Hemisphere
(e.g., Australia, Argentina, Chile), most activity generally occurs from
April through September. In the tropics (e.g., Caribbean), influenza can
occur throughout the year.
Influenza outbreaks have been well documented in relation to travel by
train, aircraft and cruise ships because of the close quarters shared by
travellers. Individuals may be exposed to travellers originating from various
countries, and with them, various strains of influenza. As such, international
travellers may introduce influenza in parts of the world at a time when
it is not expected.
The influenza virus is generally transmitted from person to person. The
flu typically starts with a headache, chills and a cough followed rapidly
by a fever, loss of appetite, muscle aches, fatigue, runny nose, sneezing,
water eyes, and throat irritation.
Complications such as pneumonia may occur, especially in the following
high risk groups: adults and children with cardiac or pulmonary disorders
severe enough to require regular medical follow-up or hospital care: people
age 65 years or older; adults and children with chronic conditions, such
as diabetes mellitus and other metabolic diseases, cancer, immune deficiencies,
immunosuppression (due to underlying disease and/or therapy), renal disease,
anemia, hemaglobinopathies, children and adolescents with conditions treated
for long period with acetylsalicylic acid (aspirin); and HIV-infected persons.
Vaccination against influenza or preventative therapy for a potential exposure
to influenza is available. Preventative therapy is not a substitute for
prevention by vaccination except when the vaccine is contraindicated or
was not given prior to the onset of influenza exposure and may be considered
for those at high risk for influenza-related complications.
Recommendations
The Public Health Agency of Canada recommends that prior to travel all travellers should consult
their personal physician or a travel medicine clinic to assess their individual
health risks including their risk for influenza. In consultation with a
physician, the need for influenza vaccination or the need to carry prophylactic
medication can be assessed. Travellers at high risk for complications from
influenza should take the opportunity to vaccinate themselves against pneumococcal
disease if they haven't already done so.
Travellers are reminded that regular hand washing is another way to help
minimize your risk. By washing your hands often, you will reduce your chance
of becoming infected after touching contaminated surfaces.
For more information:
The Public Health Agency of Canada produces weekly FluWatch reports,
summarizing influenza surveillance activities in Canada.
For information on influenza or the flu vaccine, visit Health Canada's Flu Information web site.
For international reports of the flu, visit the World
Health Organization influenza
web site or the Centres
for Disease Control .
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