403
ORIGINAL ARTICLE
Characteristics of Travelers to Asia Requiring Multidose Vaccine
Schedules: Japanese Encephalitis and Rabies Prevention
Xaviour J. Walker, MD, MPH,∗ Elizabeth D. Barnett, MD,† Mary E. Wilson, MD,‡
William B. Macleod, ScD,§ Emily S. Jentes, PhD, MPH,|| Adolf W. Karchmer, MD,¶#
Davidson H. Hamer, MD,§∗∗ Lin H. Chen, MD,#†† for the Boston Area Travel Medicine
Network (BATMN)
Hopkins Bloomberg School of Public Health, Baltimore, MD, USA; † Section of Pediatric Infectious Diseases, Boston
Medical Center and Boston University School of Medicine, Boston, MA, USA; ‡ Harvard T. H. Chan School of Public Health,
Boston, MA, USA; § Center for Global Health and Development, Boston University School of Public Health, Boston, MA, USA;
|| Division of Global Migration and Quarantine, Centers for Disease Control and Prevention, Atlanta, GA, USA; ¶ Division of
Infectious Diseases, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA, USA; # Faculty of Medicine,
Harvard Medical School, Boston, MA, USA; ∗∗ Section of Infectious Diseases, Boston University School of Medicine, Boston,
MA, USA; †† Department of Medicine, Mount Auburn Hospital, Cambridge, MA, USA
∗ Johns
DOI: 10.1111/jtm.12237
Background. Japanese encephalitis (JE) and rabies are serious vaccine preventable diseases which are an important consideration
for travelers to Asia.
Methods. Five Boston-area travel clinics collected demographic data, trip information, and interventions for travelers to Asia seen
at pre-travel consultations from March 1, 2008, through July 31, 2010. We evaluated travelers for proportion vaccinated for JE
and rabies, those traveling for >1 month, and whether travelers had adequate time to complete the JE series (clinic visit ≥28 days
before departure) and rabies pre-exposure prophylaxis (clinic visit ≥21 days before departure).
Results. Among 15,440 travelers from five Boston Area Travel Medicine Network travel clinics, Asia was the most common
destination region, visited by 5,582 (36%) of travelers. Among these travelers, 4,810 (86%) planned to travel to only one Asian
subregion. Median trip duration was 17 days, with more than 20% traveling for >1 month. The most common destinations were
South (41%), Southeast (26%), and East (23%) Asia. Of those traveling to South, Southeast, or East Asia, over one-third with
trips >1 month had insufficient time to complete a series for either JE or rabies vaccine. Overall, only 10% of travelers were
vaccinated (past and pre-travel visit) for either JE or rabies, with lowest percentages among travelers visiting friends and relatives.
Most travelers received advice on vector precautions (96%) and rabies prevention, which included avoiding animal contact, washing
wounds, and obtaining appropriate post-exposure prophylaxis (88%).
Conclusion. Given the insufficient time for completion and relatively low vaccination rates, greater awareness of earlier pre-travel
consultations, at least 4–6 weeks before travel, and accurate risk assessment for travelers are important. Effective counseling about
vector avoidance, rabies, and animal bite prevention and management remains critical.
A
sia has experienced growth in international tourist
arrivals, a 6% increase overall and 10% for
Parts of this paper were presented at the Asia Pacific Travel
Health Conference in Singapore, May 2012, and the American
Society of Tropical Medicine and Hygiene in Washington, DC
in November 2013.
Corresponding Author: Lin H. Chen, MD, Department of
Medicine, Mount Auburn Hospital, 330 Mount Auburn Street,
Cambridge, MA 02138, USA. E-mail: [email protected]
Southeast Asia in 2013.1 Japanese encephalitis (JE)
and rabies, two serious and potentially fatal diseases,
present unique challenges for travelers to Asia.2,3
Travelers on longer trips, travel during peak transmission season, rural area stays, and/or outdoor activities
face increased risk.2,3
JE can be prevented by mosquito avoidance and
vaccination, previously with the three-dose mouse
brain-derived vaccine (JE-MB) and, since 2009, with
the two-dose (days 0, 28) Vero cell-derived vaccine
(JE-VC).4 Rabies can be prevented after an animal
© 2015 International Society of Travel Medicine, 1195-1982
Journal of Travel Medicine 2015; Volume 22 (Issue 6): 403–409
404
exposure with timely administration of post-exposure
prophylaxis (PEP), consisting of a series of four rabies
vaccine doses and one dose of rabies immune globulin (RIG) for those previously unvaccinated.5 Rabies
pre-exposure prophylaxis (PrEP) with three doses
of vaccine (days 0, 7, and 21 or 28) reduces the
post-exposure vaccine need to two doses and eliminates
the need for RIG whose supply is particularly unreliable
in developing countries.3,6 The Advisory Committee on
Immunization Practices (ACIP) recommends JE vaccination for travelers on stay ≥1 month in endemic areas
during the transmission season, and also shorter stays
with outdoor rural visits/activities, accommodations
with suboptimal screening, destinations with ongoing
JE outbreak, and uncertain plans.2,4 Similarly, ACIP
recommends rabies PrEP based on rabies prevalence at
destination, availability of anti-rabies biologics, planned
activities, and duration of stay or repeat travel.3,5
We analyzed data from travelers seen at Boston
Area Travel Medicine Network (BATMN) clinics to
understand JE and rabies vaccine use for travelers to
Asia, with a focus on the influence of time to departure
and travel purpose.
Methods
BATMN, a research collaboration of five Boston-area
travel clinics, collected demographic data, trip information, and interventions for travelers seen at pre-travel
consultations from March 1, 2008, through July 31,
2010. Institutional Review Board (IRB) approvals were
obtained at all clinic sites. The US Centers for Disease
Control and Prevention (CDC) determined that CDC
participation did not require IRB review. Analyses were
performed using SAS version 9.4 (SAS Institute Inc.,
Cary, NC, USA).
First, characteristics and JE and rabies immunization
status of travelers visiting one of five UN subregions7
of Asia (travelers to multiple subregions were excluded)
were analyzed by using frequencies for discrete demographic variables and medians and interquartile ranges
(IQRs) for continuous variables. Second, we examined
JE and rabies vaccinations among travelers to South,
Southeast, and East Asia, the three subregions with both
JE and rabies risk, with respect to reasons for travel
(if the traveler had multiple reasons for travel, they
were excluded from this analysis), trip duration, and
the number/proportion of travelers with adequate time
to complete the JE series (clinic visit ≥28 days before
departure) and rabies PrEP (clinic visit ≥21 days before
departure).5,6 Finally, although JE transmission can
occur year-round in the tropical and subtropical areas,
the months of May through October are considered to
be the higher transmission period for most temperate
areas. Therefore, we analyzed the JE vaccination rates
for travelers visiting South, Southeast, and East Asia
during the May to October higher transmission season
and traveling for ≥1 month.8
J Travel Med 2015; 22: 403–409
Walker et al.
Travelers who did not receive the recommended
number of JE or rabies vaccinations were considered
not fully immunized. We calculated prevalence ratios
(PR) and 95% confidence intervals (CI) of unvaccinated
travelers with trips ≥1 month. Based on travelers who
were JE and rabies vaccine-naive but initiated those
vaccines and were departing in <28 days or <21 days,
we estimated the number/proportion who might need
to complete these immunizations during travel.
Results
Among 15,440 travelers, 5,582 (36%) planned travel
to Asia. Of those, 4,810 (86%) planned travel to only
one of the five subregions (Table 1). Median age of
these travelers was 37 years; 47% were male; 74% were
white, 19% Asian, and 3% black. Median trip duration
was 17 days; 20% traveled for ≥1 month. Median time
to departure was 23 days; 58% were leaving within 28
and 45% within 21 days. Common reasons for travel
were tourism (57%), business (21%), and visiting friends
and relatives (VFR) (18%). More travelers visited South
(41%), Southeast (26%), and East (23%) Asia than West
(10%) and Central (<1%) Asia. Visits to South and
Southeast Asia had the highest proportions of VFR
travelers (23% and 21%, respectively). Trips to Central
Asia were longer in duration (37% ≥1 month) compared
with other subregions (22%) (p = 0.03).
Of the 5,097 Asia travelers going to South, Southeast, or East Asia, 4,115 (81%) reported one reason for
travel (Table 2). Of the 4,102 reporting information on
vaccination (either past or at pre-travel clinic visit), a
total of 408 (10%) reported receiving JE vaccine and
415 (10%) reported receiving rabies PrEP (including
in past and at pre-travel visit). For travelers with trip
duration ≥1 month, 27% and 23% completed JE and
rabies vaccination (past and at pre-travel visit), respectively. Vaccination rates for JE and rabies were lowest
for VFR travelers (both 6%) (Table 2). Of travelers
on trips ≥1 month and lacking full JE vaccination, 355
(43%) of 826 were seen within 28 days before departure.
Similarly, 311 (36%) of 864 with trips ≥1 month lacking
full PrEP were seen within 21 days before travel. Among
nonvaccinated travelers, VFR were more likely to travel
≥1 month and depart within 28 or 21 days of the travel
clinic visit compared with tourists (JE: PR = 1.85;CI
1.53–2.25; rabies: PR = 1.80; CI 1.44–2.25). Most
travelers received advice on vector precautions (96%)
and rabies prevention, which included avoiding animal
contact, washing wounds, and obtaining appropriate
PEP (88%) (Table 1).
The majority of travelers to Asia were visiting
JE-endemic countries; of all 5,097 Asia travelers, 4,459
(88%) were visiting JE-endemic countries in South,
Southeast, or East Asia. The five most commonly visited countries reported were India, China, Thailand,
Vietnam, and Cambodia, all considered JE-endemic. Of
those reporting dates of travel to South, Southeast, and
South Asia
1,102
48% (525/1,102)
42 (26–57)
15 (12–23)
11% (118/1,085)
7% (70/1,085)
24 (13–42)
44% (321/736)
56% (414/736)
3% (27/1,038)
78% (808/1,038)
16% (161/1,038)
2% (16/1,038)
0% (1/1,038)
0% (0/1,038)
2% (18/1,038)
88% (844/964)
82% (897/1,095)
24% (259/1,095)
2% (20/1,095)
7% (72/1,095)
61% (716/1,167)
13% (147/1,167)
22% (261/1,167)
11% (129/1,167)
1% (13/1,167)
3% (39/1,167)
95% (814/857)
81% (697/859)
46% (577/1,265)
34 (25–52)
19 (14–30)
17% (208/1,252)
6% (72/1,252)
26 (12–42)
42% (349/837)
54% (450/837)
1% (15/1,194)
72% (861/1,194)
22% (259/1,194)
2% (21/1,194)
0% (2/1,194)
0% (4/1,194)
2% (19/1,194)
85% (959/1,133)
79% (1,031/1,302)
30% (394/1,302)
4% (57/1,302)
4% (52/1,302)
65% (823/1,267)
21% (260/1,267)
12% (156/1,267)
6% (74/1,267)
5% (65/1,267)
1% (14/1,267)
98% (949/970)
90% (887/982)
East Asia
1,265
Southeast Asia
Characteristics of BATMN travelers to five subregions of Asia*
Number of travelers
1,954
Traveler characteristics
Male
49% (951/1,954)
Age of traveler
Median age in years (IQR)
36 (26–49)
Trip duration
Median duration of trip in days (IQR)
16 (12–30)
Proportion traveling for 1–4 months
16% (317/1,937)
Proportion traveling >4 months
4% (72/1,937)
Time to departure
Median days to departure (IQR)
22 (11–35)
Proportion departing within 21 days
47% (599/1,263)
Proportion departing within 28 days
62% (783/1,263)
Race/ethnicity
Black
2% (36/1,828)
White
72% (1,315/1,828)
Asian
21% (391/1,828)
Hispanic/Latino
2% (30/1,828)
Native American/Pacific Islander
0% (1/1,828)
Middle Eastern
1% (12/1,828)
Bi/multiracial
1% (23/1,828)
Primary language
Primary language = English
87% (1,541/1,779)
Travel accommodation (>1 accommodation possible)†
Hotel or hostel
74% (1,479/1,999)
Home/local residence
33% (668/1,999)
Tent
4% (70/1,999)
Other
3% (65/1,999)
Reason for travel (>1 reason possible)†
Tourism
47% (934/1,979)
Visiting friends and relatives
23% (450/1,979)
Business
28% (550/1,979)
Education/research
7% (140/1,979)
Missionary/volunteer
4% (84/1,979)
Other purpose of trip
1% (24/1,979)
Advice and counseling
Vector precautions
97% (1,436/1,481)
Rabies precautions/animal contact
91% (1,355/1,483)
Parameter
Table 1
94% (330/352)
83% (293/352)
67% (312/463)
10% (46/463)
12% (54/463)
7% (31/463)
3% (15/463)
9% (43/463)
80% (381/476)
20% (97/476)
6% (28/476)
13% (64/476)
82% (350/427)
9% (38/432)
73% (317/432)
7% (31/432)
2% (8/432)
0% (0/432)
4% (16/432)
3% (11/432)
20 (10–44)
50% (164/327)
60% (197/327)
17 (14–29)
16% (69/446)
6% (27/446)
46 (28–61)
46% (213/459)
459
West Asia
92% (23/25)
84% (21/25)
53% (17/32)
0% (0/32)
16% (5/32)
0% (0/32)
16% (5/32)
22% (7/32)
80% (24/30)
37% (11/30)
3% (1/30)
0% (0/30)
86% (25/29)
0% (0/27)
96% (26/27)
0% (0/27)
0% (0/27)
0% (0/27)
0% (0/27)
0% (0/27)
40 (21–52)
25% (5/20)
30% (6/20)
25 (18–48)
27% (8/30)
10% (3/30)
55 (34–66)
50% (15/30)
30
Central Asia
96% (3,552/3,685)
88% (3,253/3,701)
57% (2,802/4,908)
18% (903/4,908)
21% (1,026/4,908)
8% (374/4,908)
4% (182/4,908)
3% (127/4,908)
78% (3,812/4,902)
29% (1,429/4,902)
4% (176/4,902)
5% (253/4,902)
86% (3,719/4,332)
3% (116/4,519)
74% (3,327/4,519)
19% (842/4,519)
2% (75/4,519)
0% (4/4,519)
1% (32/4,519)
2% (71/4,519)
23 (11–40)
45% (1,438/3,183)
58% (1,850/3,183)
17 (13–30)
15% (720/4,750)
5% (244/4,750)
37 (26–53)
47% (2,281/4,810)
4,810
All subjects
JE Rabies BATMN
405
J Travel Med 2015; 22: 403–409
406
1,627
60
629
398
10
0
5
0
132
13
71
33
428
13
173
121
691
17
226
172
Missing values
Missing time to departure
Missing duration of trip
Missing accommodation
Missing purpose of trip
366
17
154
72
4% (25/624)
6% (31/532)
7% (49/685)
10% (64/619)
6% (65/1,035)
11% (102/958)
J Travel Med 2015; 22: 403–409
BATMN = Boston Area Travel Medicine Network; IQR = interquartile range; PrEP = pre-exposure prophylaxis.
*Only including travelers to one region in Asia (N = 4,810)
†Because each traveler can indicate >1 accommodation and >1 reason for travel, the denominators include the total numbers of those parameters counted and may exceed the number of travelers to each subregion.
‡Review of the details for those two travelers found that they were traveling to numerous other countries. One of them had previous Japanese encephalitis vaccine and we speculate that this is a frequent traveler getting updated for more
possible trips to Asia in the future. Unfortunately, the data have no identifiers. Therefore we cannot trace the record to review the rationale of these decisions.
6% (147/2,611)
9% (220/2,350)
12% (2/17)
33% (5/15)
2% (6/250)
8% (18/226)
7% (288/4,240)
5% (235/4,702)
0% (0/24)
11% (3/28)
11% (130/1,145)
7% (89/1,243)
5% (91/1,742)
5% (90/1,919)
Immunized in travel clinic
Japanese encephalitis series
Rabies PrEP
Past immunization
Japanese encephalitis series
Rabies PrEP
7% (65/924)
4% (40/1,065)
1% (2/405)‡
3% (13/447)
All subjects
Parameter
Table 1
Continued
South Asia
Southeast Asia
East Asia
West Asia
Central Asia
Walker et al.
East Asia, 1,811 of 2,926 (62%) travelers visited during
May to October (higher transmission season), and of
these, 552 of 2,903 (19%) were traveling for ≥1 month.
Among 546 travelers who should have received JE
vaccination based on trip duration and travel during
the higher transmission season, 23 of them (4%) had
received JE vaccine in the past and 156 of 546 (29%)
received it in clinic [179/546 (33%) total]. Among the
remaining travelers, 227 (42%) were leaving within
28 days and 140 (25%) had sufficient time but were not
immunized.
Discussion
Among BATMN travelers, South Asia was the most
commonly visited subregion. We found that over
one-third of travelers with trips ≥1 month had insufficient time before departure to complete the JE and
rabies series. Although we were unable to determine
specifically whether vaccine would be indicated for
each traveler, we found that the percentage of travelers
vaccinated for both JE and rabies was low. Although
JE is diagnosed rarely in travelers (55 cases published
over 36 years), the high case-fatality ratio (18%) and
long-term sequelae (44%) suggest that vaccination
should be considered for people at high risk.2,4 Rabies
is also rare in travelers (22 cases reported over the last
decade), but at-risk animal exposure occurs in 0.4% of
travelers per month of travel,3 and treating an exposure
can be complicated by low rates of PrEP and lack of
RIG.3,6,8 – 10 Travelers cite vaccine cost as the major
impediment, although lack of risk awareness among
travelers and health providers and insufficient time
to complete PrEP also contribute to low vaccination
rates.3,11,12
Our results indicate that a large proportion of travelers lack time for vaccine completion. Furthermore, VFR
travelers were vaccinated less than other travelers, were
more likely than tourists to travel for ≥1 month, and
were less likely to have sufficient time to complete JE
and rabies series. In order to improve vaccine uptake,
clearer guidance and communication is needed to advise
travelers to seek pre-travel consultations at least 4 to
6 weeks in advance of their travel. Community outreach (organizations sponsoring travel to risk areas, cultural/ethnic centers) and primary care providers might
be effective in encouraging travelers to seek pre-travel
health consultations earlier. If earlier consultations are
not possible, recent studies investigating accelerated JE
and rabies schedules could provide alternative options
for time-limited travelers.13,14
Although almost all of our travelers received advice
on preventing vector-borne diseases and animal bites,
vaccination practices varied. As found elsewhere,
vaccine cost and communication might have been significant barriers.11,15 The cost barrier is likely to remain,
thus we need effective communication strategies regarding clinician communication to travelers. The approach
57 (16–135)
67% (207/310)
VFR = visiting friends and relatives; IQR = interquartile range; JE = Japanese encephalitis; CI = confidence intervals.
Statistically significant variables are shown in bold.
*Only travelers with one reason for travel and going to South, Southeast, and East Asia are included (N = 4,115).
3.2% (10/314)
20.1% (63/314)
23% (73/314)
66% (137/207)
0.85 (0.76, 0.95)
33% (45/137)
1.21 (0.90, 1.63)
13 (8–21)
19% (154/820)
29 (16–49)
34% (76/227)
47% (106/227)
3.7% (75/2,004)
3.6% (27/745)
4.8% (40/831)
5.4% (108/2,004) 2.3% (17/745)
3.7% (31/831)
9% (183/2,004)
6% (44/745)
9% (71/831)
78% (331/424)
88% (211/241)
74% (114/154)
1.00 (reference) 1.12 (1.05, 1.20) 0.95 (0.85, 1.05)
27% (90/331)
49% (103/211)
45% (51/114)
1.00 (reference) 1.80 (1.44, 2.25) 1.65 (1.26, 2.15)
21 (14–30)
32% (241/746)
17 (14–25)
21% (424/1,998)
16 (8–30)
60% (348/583)
72% (421/583)
36% (113/314)
314
7.3% (11/151)
16.6% (25/151)
24% (36/151)
67% (55/82)
0.86 (0.73, 1.01)
27% (15/55)
1.00 (0.63, 1.60)
3% (5/151)
24% (36/151)
27% (41/151)
59% (48/82)
0.77 (0.64, 0.94)
38% (18/48)
1.16 (0.78, 1.72)
30 (17–76)
55% (82/150)
29 (16–47)
34% (36/107)
48% (51/107)
38% (58/151)
151
Education/research Missionary/volunteer
5% (15/314)
24% (75/314)
29% (90/314)
60% (124/207)
0.79 (0.70, 0.90)
40% (50/124)
1.24 (0.95, 1.62)
20 (9–32)
52% (279/535)
67% (359/535)
27 (14–44)
38% (515/1,352)
51% (686/1,352)
67% (558/833)
833
Business
1% (10/745)
4% (30/830)
4% (32/745)
4% (34/830)
6% (42/745)
8% (64/830)
86% (208/241)
70% (108/154)
1.14 (1.06, 1.23) 0.93 (0.83, 1.04)
60% (125/208)
44% (47/108)
1.85 (1.53, 2.25) 1.34 (1.03, 1.75)
43% (324/752)
43% (870/2,008)
2% (34/2,005)
7% (131/2,005)
8% (165/2,005)
76% (321/424)
1.00 [reference]
32% (104/321)
1.00 (reference)
752
VFR
2,008
Tourism
7.0% (4/57)
7.0% (4/57)
14% (8/57)
73% (16/22)
0.93 (0.72, 1.21)
44% (7/16)
1.61 (0.90, 2.88)
0% (0/57)
11% (6/57)
11% (6/57)
77% (17/22)
1.02 (0.81, 1.29)
65% (11/17)
2.00 (1.36, 2.94)
21 (14–90)
41% (22/54)
24 (14–41)
46% (20/44)
61% (27/44)
53% (30/57)
57
Other reason
36% (311/864)
4.1% (167/4,102)
6.0% (248/4,102)
10% (415/4,102)
77% (864/1,130)
43% (355/826)
2% (94/4,102)
8% (314/4,102)
10% (408/4,102)
73% (826/1,130)
17 (14–30)
28% (1,130/4,078)
23 (11–39)
45% (1,274/2,848)
58% (1,650/2,848)
48% (1,953/4,115)
4,115
All subjects
Comparison of time to departure, JE vaccination rates, and rabies vaccination rates based upon reason for travel among travelers to South, Southeast, and East Asia*
Number of travelers
Traveler characteristics
Male (%)
Time to departure
Median days to departure (IQR)
Proportion departing within 21 days
Proportion departing within 28 days
Trip duration
Median trip duration (days) (IQR)
More than 1 month
JE vaccine
Vaccinated in past
Vaccinated in clinic
Total immunized
Trip ≥1 month and not fully immunized
Prevalence ratio (95% CI)
Trip ≥1 month not fully immunized departing within 28 days
Prevalence ratio (95% CI)
Rabies vaccine
Vaccinated in past
Vaccinated in clinic
Total immunized
Trip ≥1 month and not fully immunized
Prevalence ratio (95% CI)
Trip ≥1 month not fully immunized departing within 21 days
Prevalence ratio (95% CI)
Parameter
Table 2
JE Rabies BATMN
407
J Travel Med 2015; 22: 403–409
408
of aggregate, multitrip risk assessment regarding
vaccinations for frequent travelers may particularly
benefit VFR travelers who plan to visit high-risk areas
repeatedly.16 Another important consideration for
vaccination is the possibility of alterations in destinations, planned activities, length of stay, and areas of
stay. In fact, another study found that 40% of travelers surveyed reported staying in a rural zone or with
local people although they had not planned to do so.17
Pre-travel discussions between clinicians and patients
regarding rabies and JE vaccination should include the
possibilities of changes in plans, and thus risk.
Our study is limited by potential differences between
travelers who seek pre-travel advice in travel clinics,
travelers seen in primary care practices or pharmacies, and those who do not seek travel advice. Results
may not be representative of communities outside the
Boston area. JE vaccine supply changed from JE-MB to
JE-VC vaccine in May 2009. Because both required 28
to 30 days to administer, insufficient time to complete
JE vaccines likely affected both similarly, but vaccine
shortages before May 2009 may have limited JE vaccine
use. Importantly, the estimates based solely on region
of travel (rather than specific destination), trip duration, and transmission season may not reflect the traveler’s JE risk accurately. The database lacked detailed
descriptions regarding itinerary (including sub-national
destinations), accommodations, and activities (such as
rural visits, stays in unscreened housing, nighttime outdoor events) that would allow for finer determination of
possible JE exposure. Similarly, the lack of destination
details might have influenced decisions regarding rabies
vaccination that were not captured here. Also, analyzing
the data by region of travel may have over- or underestimated which travelers should have received vaccines or
counseling on disease risk.
Although travelers in our investigation sought
pre-travel health consultations from specialized travel
medicine clinics, many travelers seek pre-travel advice
from nontravel medicine providers.18,19 Because travel
assessments can be complex, as indicated above, clinicians with advanced travel medicine knowledge might
provide travelers with more comprehensive risk assessments. A previous survey of travel medicine providers
in the US found that clinician knowledge, attitudes, and
practices are better in those with ISTM or ASTMH
certification compared with providers without such
certification,20 therefore educational programs (courses,
modules) for clinicians should be encouraged. For particularly high-risk travelers, it may be feasible to refer
or arrange the completion of these vaccine series at
reliable facilities during travel, guided by sources such
as ISTM or ASTMH travel clinic directories, although
vaccine safety and availability in the destination country
might be variable.
Finally, among about 15 JE vaccines in use worldwide, 3 new generation JE vaccines are available in some
countries.21 Also based on the SA 14-14-2 JEV strain,
the two besides JE-VC are: (1) a live-attenuated hamster
J Travel Med 2015; 22: 403–409
Walker et al.
kidney cell-derived JE vaccine, used in China and other
Asian countries; and (2) a live-attenuated chimeric vaccine licensed and available in Australia since 2010 and in
several other Asian countries. Both live-attenuated vaccines are administered as a single dose; however, these
vaccines are not licensed for use in the United States.
Limited data exist on the safety and vaccine interchangeability among some JE vaccines, specifically between
JE-MB and JE-VC.21 – 24
Conclusion
JE and rabies vaccination rates were low among
BATMN travelers despite visiting the region endemic
for both diseases, particularly for VFR travelers. Cost
and insufficient time likely contributed to nonvaccination. Broadening awareness of need for earlier pre-travel
consultations (≥4–6 weeks before travel) may improve
ability to provide both JE and rabies PrEP. Providing
accurate, reliable, and clear information about disease
risks and availability of vaccines allows travelers to
optimize decisions regarding vaccination. Effective
counseling about vector avoidance, rabies, and animal
bite prevention and management remain critical.
Acknowledgments
In addition to the authors, members of the Boston Area
Travel Medicine Network who contributed data include
L. Kogelman, MD, Tufts Medical Center, and W. W.
Ooi, MD, Lahey Clinic Medical Center. We thank
Erika Gleva, Christine Benoit, Rebecca Dufur, Deborah
Gannon, and Manveen Bhussar for their assistance with
data collection and entry. Xaviour J. Walker is a former
medical resident and staff at Mount Auburn Hospital,
Cambridge, Massachusetts, USA.
This research was funded by a cooperative agreement (1 U19CI000508-01) between the Centers for
Disease Control and Prevention and Boston Medical
Center. The findings and conclusions in this report are
those of the authors and do not necessarily represent
the official position of the Centers for Disease Control
and Prevention.
[Correction added on 15 October 2015, after first
online publication: Xaviour J. Walker’s previous affiliation was added.]
Declaration of Interests
L. H. C. is an advisor for Shoreland, Inc. and has
received speaker travel support and honoraria from
GSK, and royalties from Wiley Blackwell. E. D. B.
reports clinical trials funding from Intercell (now Valneva) for JE vaccine Ixiaro in children.
The authors report no financial disclosures relevant
to this work.
409
JE Rabies BATMN
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