IMMUNIZATIONS - Medicine for Mountaineering and Other Wilderness Activities - page 52

Persons at high risk for complications of influenza and those who were not vaccinated
with influenza vaccine during the preceding fall or winter should consider receiving influ-
enza vaccine before travel if they plan any of the following:
Travel to the tropics
Travel with organized tourist groups at any time of year
Travel to the Southern Hemisphere during April through September
Two influenza vaccines are available: an inactivated (killed-virus) vaccine that must be
injectedandanattenuatedlive-virusvaccinethatisadministeredasanintranasalspray.The
inactivated vaccine is cheaper and is recommended for all routine immunizations.
The nasal-spray flu vaccine (FluMist®) is approved for use in people two to forty-nine
years of age who are not pregnant and who do not have an underlying medical condition
that predisposes them to influenza complications. Persons at high risk for influenza-related
complications and severe disease include children aged six months to five years, pregnant
women, persons older than fifty years, persons of any age with chronic medical conditions
such as diabetes, heart disease, or lung disease, and health care workers.
More information about the nasal-spray flu vaccine is available at the CDC site
( www.cdc.gov/flu/about/qa/nasalspray.htm ) . Detailed information about the prevention
and control of influenza is available at www.cdc.gov/mmwr/preview/mmwrhtml/
rr5306a1.htm .
Japanese Encephalitis
Japanese encephalitis isamajor problem inmuchofAsiabutisanuncommon infection
among travelers, among whom CDC investigators estimate the incidence to be less than
one per million ( Fig. 5-1 ). Vaccination is recommended only for travelers who plan to
spend a month or longer in endemic areas during the transmission season—which is dif-
ferent for each country. (Detailed information about different countries is available at
www.cdc.gov/travel/diseases.htm#hepa .) However, CDC warns that travelers with extens-
ive unprotected outdoor, evening, and nighttime exposure in rural areas, such as might be
experienced while bicycling, camping, or engaging in certain occupational activities, may
be at high risk even if their trip is brief. To avoid being bitten by the mosquitoes that trans-
mit the infection, repellents, appropriate clothing, and mosquito nets must be used.
Ixiaro®, a new vaccine for Japanese encephalitis, was licensed by the FDA on March
30, 2009. (The old vaccine is no longer being produced.) The new vaccine is considered
safer and freer from the side effects (which included anaphylactic reactions) associated
with the old vaccine. It is indicated for active immunization against JE virus for persons
seventeen years of age and older.
Ixiaro® is an inactivated vaccine based on cell culture technology. It provides a good
immune response and is well tolerated. The vaccine is provided as a ready-to-use liquid