It’s that time of year again. Many of your patients will join the 80.2 million Americans with plans for international travel this summer.
In 2016, Mexico (31.2 million) and Canada (13.9 million) were the top two destinations of U.S. residents. Based on 2016 U.S. Commerce data, an additional 35.1 million Americans headed to overseas destinations, including 9% who traveled with children. Vacation and visiting friends and relatives accounted for 55% and 27% of the reasons for all travel, respectively. Education accounted for 4% of travelers.
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Required versus recommended vaccines
The goal of a required vaccine is to prevent international spread of disease. The host country is protecting its citizens from visitors importing and facilitating the spread of a disease. Yellow fever and meningococcal disease are the only vaccines required for entry into any country. Entry requirements vary by country. Yellow fever may be an entry requirement for all travelers or it may be limited to those who have been in, or have had transit through, a country where yellow fever can be transmitted at least 6 days prior to the arrival at their final destination – a reminder that the sequence of the patient’s itinerary is important. In addition, just because a vaccine is not required for entry does not mean the risk for exposure and acquisition is nonexistent.
In contrast, recommended vaccines are for the protection of the individual. Travelers may be exposed to vaccine-preventable diseases that do not exist in their country (such as measles, typhoid fever, and yellow fever). They are at risk for acquisition and may return home infected, which could create the potential to spread the disease to susceptible contacts.
Most travelers comprehend required vaccines but often fail to understand the importance of receiving recommended vaccines. Lammert et al. reported that, of 24,478 persons who received pretravel advice between July 2012 and June 2014 through Global TravEpiNet, a national consortium of U.S. clinics, 97% were eligible for at least one vaccine. The majority were eligible for typhoid (n = 20,092) and hepatitis A (n = 12,990). Of patients included in the study, 25% (6,573) refused one or more vaccines. The most common reason cited for refusal was a lack of concern about the illness. Travelers visiting friends and relatives were less likely to accept all recommended vaccines, compared with those who were not visiting friends and relatives (odds ratio, 0.74) (J Trav Med. 2017 Jan. doi: 10.1093/jtm/taw075). In the United States, international travel remains the most common risk factor for acquisition of both typhoid fever and hepatitis A.