July 31, 2013

Jay S. Keystone, MD

KeystoneSpecial thanks to Jay S. Keystone, MD of the University of Toronto and Toronto General Hospital for this guest blog post on travel vaccines. Dr. Keystone will be a featured speaker at the NFID 2013 Fall Clinical Vaccinology Course, November 15-17, 2013 in Cambridge, MA.

Recently, in my travel clinic, I asked a patient when he was leaving for his 3 month vacation in Southeast Asia. The answer was, “tomorrow!”

Unfortunately, last-minute overseas travelers requesting health advice is a common occurrence–up to one third of travelers seek travel health advice in the seven days prior to departure. What is wrong with waiting for the last minute to seek health advice before travel? From an immunization point of view, it may be too late to complete a vaccine schedule. For example, Japanese encephalitis vaccine consists of 2 doses one month apart, while even the accelerated combined hepatitis A/B schedule still needs 3 weeks. The rule in vaccine administration is that you can always lengthen a schedule but not shorten it.

Furthermore, for those of us of retirement age (now 75+) who plan to spend our remaining days and dollars on international travel, our immune system is on the wane to the point that it takes us much longer to develop a protective immune response from vaccines. For example, within 2 weeks, those under 40 will have 90% protection against hepatitis A but only 77% protection for older travelers.

Does this mean that last-minute travelers should not bother to seek pre-travel health advice? The answer is an emphatic no!  Incomplete vaccine schedules can still provide partial protection. Health advice given six to eight weeks before travel will ensure that all necessary immunizations can be administered. The bottom line: don’t put health advice on the bottom of your travel checklist. Seek advice early if possible, but make sure you seek advice!

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