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John D. Wilson, M.D.
1200 Hilyard St., Suite S-560
Eugene, Oregon 97401 USA
541/343-6028 fax 485-7702
www.TravelClinicOregon.com |
INFLUENZA AND INTERNATIONAL
TRAVEL - January 2005
I will try to outline a reasonable benefit/cost/risk analysis of whether to
give influenza vaccine to international travelers.
Influenza outbreaks have been documented aboard cruise ships. Air travelers
disperse so quickly after landing that it would be impossible to document
influenza transmission aboard flights. Influenza is probably passed (like
meningococcal disease) by short range droplet as well as person-to-person
contact; crowding of people who congregate from multiple geographic sites
(increased risk for meningococcal disease in military recruits in barracks,
college students in dorms, and travelers to the Hajj). Influenza has a much
higher attack rate than meningococcal disease. Fears about ventilation aboard
aircraft are probably exaggerated. I am less worried about aircraft ventilation
than I am about someone coughing within a few rows of my seat. Maybe also who
touched the doorknob I touch just before I scratch my nose, and did he wash his
hands after he coughed into them.
The CDC recommends influenza vaccine if a person will be mixing with crowds
which may contain international visitors, regardless of the time of year. This
would obviously include any air traveler to a destination outside the US. If you
think about it, influenza is probably the most vaccine-preventable disease a
traveler is likely to contract.
Influenza tends to occur throughout the year (rather than seasonally) the closer
one gets to the equator. We already know about influenza occurring in the
temperate southern hemisphere during their winter. Each year, I try to have
influenza vaccine available for all travelers right up to the June 30 expiration
date, and regret not having vaccine available starting July 1. I documented
influenza in a traveler returning from Brazil in July, 2002.
I make sure my patients, family, staff and myself are all appropriately
immunized against influenza each October, even if we are not traveling, and have
been doing so for 25 years.
Domestically, in the US, we have the situation that the vaccine works least well
in the patients who need it most (infants and the elderly and the chronically
ill), and until we can also immunize the people around them, we will likely
continue to have an estimated 30,000 deaths and millions of cases each winter.
Unfortunately, we have a media-driven feast/famine guessing game every winter.
Federal support for a partial buy-back of unopened vials, operated through the
manufacturers, would tend to insure that we will not be reluctant to purchase
enough vaccine to meet the needs of our practices. After all, this IS a public
health problem.
I believe that, once production and supply problems are worked out, influenza
vaccine could reasonably be offered to each person in the US over age 6 months.
I am hopeful that a recombinant DNA technology will be found which will make
manufacture more reliable, and more responsive to changes in emerging new
strains of influenza virus.
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