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ORIGINAL ARTICLES
Knowledge, Attitudes, and Practices of Business Travelers Regarding Influenza and the Use of Antiviral Medication Salome Helfenberger, MD,∗ Alois Tschopp, PhD,∗ Luc Robyn, MD,† Christoph Hatz, MD,∗ and Patricia Schlagenhauf, PhD∗ ∗ University
of Zurich Center for Travel Medicine, Institute for Social and Preventive Medicine, University of Zurich, Zurich, Switzerland; † Nestl´e Ltd Medical Services, Nestl´e, Vevey, Switzerland DOI: 10.1111/j.1708-8305.2010.00467.x
Background. This study aimed to determine the knowledge, attitudes, and practices of Swiss business travelers with regard to influenza and the use of antiviral medication. Methods. Questionnaires, available in three languages, were distributed manually and online through companies, organizations, and travel medicine specialists in Switzerland to business travelers who were traveling during the period January 2005 to April 2009. Result. In total, 661 questionnaires were fully completed and evaluated. A total of 58.9% (n = 388) of the respondents stated that they had contracted influenza in the past; some 48.6% (n = 321) of the travelers had been vaccinated against seasonal influenza at least once in their lifetime; 87.1% (n = 576) of the travelers knew that influenza can be transmitted by droplets; and 62.3% (n = 412) were aware of transmission by direct contact. Almost all respondents (96.8%; n = 633) recognized fever as a main symptom of influenza, 80.0% (n = 523) knew about muscular aches and pain, 79.5% (n = 520) about shivering, and 72.9% (n = 477) about joint pain. Some 38.0% (n = 250) of the respondents stated that the annual vaccination is their preferred prevention method for influenza, 35.6% (n = 234) would neither do an annual vaccination nor carry antiviral medication, 16.0% (n = 105) would carry antiviral medication, 8.5% (n = 56) would prefer to do both the annual vaccination and to carry antivirals, and 2.0% (n = 13) would use antivirals as influenza prophylaxis. Regarding prevention, the majority (78.9%; n = 498) of the travelers did not seek advice on influenza before going on their last business trip, 58.0% (n = 381) did not take any preventive measures against influenza, 27.2% (n = 179) had their annual vaccination, and 15.7% (n = 103) observed hand hygiene. Of the travelers, 9.7% (n = 64) carried antiviral medication on their last business trip and 7.0% (n = 46) actually used this medication. Conclusions. Business travelers have a good kowledge about the transmission and the symptoms of influenza but guidelines are needed that concisely address the indications for influenza vaccination in travelers and the carriage and use of antiviral medication.
T
he recent influenza A (H1N1) pandemic has brought influenza into the infectious disease limelight. In Europe, more than 29% of all confirmed influenza A (H1N1) pandemic cases were travel related and were registered after importation into European Union/European Economic Area countries.1 Seasonal influenza affects 5% to 15% of the world’s population annually and is considered to be among the most frequent vaccine-preventable infections in travelers.2,3 Corresponding Author: PD Dr Patricia Schlagenhauf, PhD, Universitiy of Zurich Center for Travel Medicine, WHO Collaborating Center for Travelers’ Health, Institute for Social and Preventive Medicine, University of Zurich, Hirschengraben 84, CH-8001 Zurich, Switzerland. E-mail:
[email protected]
The attack rate of influenza in intercontinental travelers is estimated at 1%.4 A study which analyzed travelassociated pandemic (H1N1) infection in Singapore showed that one fourth of the case-patients traveled after illness onset, and 15% became ill while traveling.5 Wagner and colleagues showed that air travel by one infectious individual, rather than causing a single outbreak of H1N1, could cause several simultaneous outbreaks, especially in Economy Class on long-haul flights.6 Fever in ill-returned travelers is a common presenting symptom and about 14% of presenting fevers can be attributed to a respiratory illness.7 In patients with severe acute respiratory syndromes, influenza viruses are prevalent 14.2%.8 Furthermore, the recent pandemic influenza showed an increased risk of infection and death among young adults who constitute a mobile population.9 In the temperate © 2010 International Society of Travel Medicine, 1195-1982 Journal of Travel Medicine 2010; Volume 17 (Issue 6): 367–373
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regions of the northern hemisphere, most influenza activity occurs from November through April, in the temperate regions of the southern hemisphere it is from April through October, whereas in the tropics the influenza virus circulates at low levels year-round.10 Thus, influenza is particularly associated with travel in the northern hemisphere during wintertime or travel in the southern hemisphere during their influenza season.11 Due to close contact of large numbers of individuals who may harbor influenza, travelers are at a higher risk for influenza.10,12,13 Air travel, in particular, facilitates the spread of influenza around the globe and as soon as influenza is spread to the top 50 global airports, the transmission is greatly accelerated. The top 50 global airports are defined as airports with the most passengers worldwide (accounting for around 70% of all airport passengers).14 Business travelers, because of their frequent travel patterns comprise an eligible target group to investigate the knowledge, attitudes, and practices (KAP) of travelers regarding the prevention and treatment of influenza. To date, some travel health advice websites recommend influenza vaccination for travelers but only if they belong to a high-risk group. Furthermore, there is no consensus on guidelines for the use of antiviral medication by travelers. Our study aims to clarify the current KAP of business travelers regarding influenza and its prevention. These data will provide an evidence base for prevention guidelines. Methods An electronic questionnaire (www.surveymonkey.com) and a small number of printed questionnaires, available in three languages, addressed the KAP of a convenience sample of Swiss business travelers regarding influenza and antiviral medication. A ‘‘business traveler’’ was defined as a person who has been traveling for professional reasons at least once during the period January 2005 to April 2009. Inclusion criteria were business as the main purpose of the trip and permanent residency in Switzerland. The questionnaires were provided to companies, organizations, and travel medicine specialists for distribution to Swiss business travelers. Data collation was done between February and April 2009. The questions focused on elucidating the level of knowledge in business travelers regarding influenza, the influenza vaccine, and the perceived need for and use of antiviral medication by this target group. Data analysis was performed with the software program Statistics Package for the Social Sciences (SPSS). Statistical significance and correlation were calculated using the chi-square (χ2 ) test and Pearson’s coefficients. Significance was determined as p < 0.05. Results The most successful distribution avenues of the questionnaires were large multinational companies who J Travel Med 2010; 17: 367–373
Helfenberger et al.
allowed us to distribute [questionnaires] electronically to their employees. A total of 661 questionnaires were evaluated, of which 294 (44.5%) were completed in German, 260 (39.3%) in English, and 107 (16.2%) in French. Most respondents were male (n = 485; 73.4%). Of the travelers, 416 (62.9%) were aged between 30 and 49 years and 178 (26.9%) were 50 years and above. Some 447 (67.6%) of the participants worked in a company with more than 1,000 employees and most of the respondents (n = 498, 75.3%) were frequent business travelers with more than 10 business trips in the peroid of the analysis. Respondents visited all the six World Health Organization (WHO) regions15 on their last business trips and recorded 1,491 stopovers together, of which 875 (58.7%) of the stopovers were in the European Region. A total of 388 (58.9%) respondents reported having already contracted influenza in the past and approximately half of the travelers (n = 321, 48.6%) had ever been vaccinated against influenza (Table 1). The factors significantly influencing a positive vaccination status were a personal history of contracting influenza (p = 0.000), knowledge of the two modes of transmission (p = 0.004), knowledge regarding high-risk groups and the complications of influenza (p = 0.001), working for a large company (p = 0.013), a high educational background (p = 0.001), and being over 40 years of age (p = 0.000). Business travelers were knowledgeable regarding the mode of transmission of influenza, the main symptoms, and complications of the infection (Table 2). For future prevention of influenza during business travel, the preferred prevention strategies are vaccination (38%) or carriage of antivirals for use at onset of symptoms (16%) (Table 3). Regarding the pretravel advice, some 80% of travelers did not get information on influenza prior to their last trip. Some 64 (9.7%) of the travelers stated that they carried antiviral tablets on their last business trip (Table 4). The lower the educational background, the larger the proportion who carried antiviral medication (p = 0.001), but due to the very small number of people with a lower education in this study this significance was interpreted as not meaningful. There were no further factors found which significantly influenced the carriage of antiviral medication. Discussion This study shows that a significant number of the business travelers carried (9.7%; n = 64) and used (7.0%; n = 46) antiviral medication on their last business trip. Another finding was that many business travelers become ill with influenza (58.9%; n = 388), half of them (48.6%; n = 321) have been vaccinated at least once, and most respondents have a good knowledge about the transmission, the main symptoms, and the complications of influenza. Weaknesses of the study are that we have no denominator data on the total
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Influenza and the Use of Antiviral Medication in Business Travelers Table 1
Demographics of participating business travelers
Language of the questionnaire German English French Nationality Swiss Other Europeans From elsewhere Sex Male Female Age (y) 20–29 30–49 50 and older Education High level (university or post-secondary institution) Lower levels No response Size of company More than 1,000 employees 50–1,000 employees Less than 50 employees Number of business trips ever taken More than 10 times 10 times or less Year of the last business trip 2009 2008 2005–2007 How much time elapsed between the decision for your last business trip and your departure? More than 2 wk 1–2 wk 1–7 d No response Number of stopovers in the different World Health Organization regions European Region Region of the Americas Western Pacific Region African Region Southeast Asia Region Eastern Mediterranean Region Have you ever had influenza? Yes Possibly No No response Have you ever been vaccinated against influenza? Yes No Don’t know No response
294 (44.5%) 260 (39.3%) 107 (16.2%) 344 (52.0%) 256 (38.7%) 61 (9.2%) 485 (73.4%) 176 (26.6%) 67 (10.1%) 416 (62.9%) 178 (26.9%) 606 (91.8%) 54 (8.2%) 1 447 (67.6%) 156 (23.6%) 58 (8.8%) 498 (75.3%) 163 (24.7%) 485 (73.4%) 162 (24.5%) 14 (2.1%)
358 (54.5%) 172 (26.2%) 127 (19.3%) 4
875 (58.7%) 283 (19.0%) 158 (10.6%) 73 (4.9%) 66 (4.4%) 36 (2.4%) 388 (58.9%) 158 (24.0%) 113 (17.1%) 2
321 (48.6%) 321 (48.6%) 18 (2.7%) 1
number of Swiss business travelers; our sample was a convenience sample; we were unable to link destination, season of travel, and influenza advice variables; and that the data were collected by questionnaires where the
Table 2 Knowledge of business travelers regarding influenza Do you know how influenza is transmitted? (multiple answers possible) Mosquitoes 38 (5.7%) Droplet infection 576 (87.1%) Dirty drinking water 26 (3.9%) Contact infection 412 (62.3%) Don’t know 41 (6.2%) Other 9 (1.4%) Which of the following symptoms are possible with influenza? (multiple answers possible) Nausea 195 (29.8%) Vomiting 172 (26.3%) Diarrhea 165 (25.2%) Fever 633 (96.8%) Dizziniess 278 (42.5%) Shivering 520 (79.5%) Headache 565 (86.4%) Muscle pain 523 (80.0%) Joint pain 477 (72.9%) Sore throat 405 (61.9%) Cough 454 (69.4%) Cold 428 (65.4%) No response 7 Which of the following statements apply to influenza? (multiple answers possible) Influenza is a harmless infection 31 (4.8%) High-risk groups for complications are the very 564 (86.8%) young, the elderly and the chronically ill people Influenza may lead to complications of underlying 532 (81.8%) diseases, pneumonia and death In Switzerland, the mortality rate due to influenza 267 (41.1%) has been estimated at between 400 and 1,000 deaths a year No response 11
respondents did not have the possibility to interact with the interviewer. Strengths of the study are the large sample size that was generated in a short time period using a user-friendly electronic questionnaire that was designed to capture the key variables required for this KAP analysis. To the best of our knowledge, no similar studies have addressed this topic, so it was not possible to compare our results with those of other studies. Although many people have a good knowledge about influenza there is a need for more information. Almost half of the travelers (48.8%, n = 321) agree that better information should be available. The business travelers would like to receive this information from public health authorities, company physicians, the internet, and travel agencies. In particular, the internet has become an important source of information about travel medicine.16 The travel health advisors were deemed less important by the respondents. This suggests that travel health clinics should position themselves more strategically as a source of information for business travelers. Of note, 78.9% (n = 498) of business travelers did not seek advice on influenza before leaving on their last business trip. J Travel Med 2010; 17: 367–373
370 Table 3
Helfenberger et al. Attitudes of business travelers regarding influenza
As a business traveler what is your preferred strategy for the prevention of influenza? Annual vaccination 250 (38.0%) Antiviral medication as 13 (2.0%) prophylaxis Carriage of antivirals in 105 (16.0%) case of illness Annual vaccination plus 56 (8.5%) carriage of antivirals No strategy, I would 234 (35.6%) prefer to take my chances No response 3 If you became ill abroad with headache and 38◦ C fever, what would you do? (multiple answers possible) If I did not improve, I would contact a local 299 (45.2%) doctor within 2–3 days. I would contact a local doctor within 24 h. 162 (24.5%) I would take antiviral tablets like Tamiflu 35 (5.3%) (oseltamivir). I would take medicines like Aspirin, Panadol 432 (65.4%) (paracetamol), or NeoCitran (phenylephrine, pheniramine, ascorbic acid, and paracetamol). Other 67 (10.1%) In your opinion, should business travelers be better informed regarding influenza? Yes 321 (48.8%) No 117 (17.8%) Don’t know 220 (33.4%) No response 3 In your opinion, who should have this responsibility? (multiple answers possible) Supervisor 42 (7.0%) Secretary 43 (7.2%) Personnel office 122 (20.3%) Media 71 (11.8%) Company’s doctor 295 (49.2%) General practitioner 86 (14.3%) Vaccination center 72 (12.0%) Pharmacy 19 (3.2%) Travel medicine specialist 100 (16.7%) Travel agency 167 (27.8%) Swiss Federal Office of 128 (21.3%) Public Health Other 45 (7.5%) No response 61
In the future, it would be important to target younger business travelers as only 29.9% (n = 20) of the respondents aged between 20 and 29 years were vaccinated against influenza at least once compared to 62.4% (n = 111) of the respondents who were 50 years or older. We were surprised to find that up to 10% of business travelers carry antiviral medication. This shows that the concept of prophylaxis and/or treatment of influenza illness is firmly anchored in this group of travelers. Some 15.9% (n = 10) of the group who carried antiviral medication used it as prophylaxis before the appearance of any symptoms and 57.1% (n = 36) took it within 2 days of illness onset to reduce the duration of symptoms. The annual vaccination was done by 27.2% (n = 179) of the business travelers, whereas J Travel Med 2010; 17: 367–373
Table 4
Practices of business travelers regarding influenza
Where did you get your information on influenza for your last business trip? (multiple answers possible) Supervisor 2 (0.3%) Secretary 2 (0.3%) Personnel office 8 (1.3%) Colleagues 18 (2.9%) Friends 11 (1.7%) Travel agency 5 (0.8%) Travel books 6 (1.0%) Internet 37 (5.9%) Pharmacy 9 (1.4%) Vaccination center 17 (2.7%) Travel medicine specialist 12 (1.9%) Company’s doctor 39 (6.2%) General practitioner 18 (2.9%) Nowhere 498 (78.9%) Other 43 (6.8%) No response 30 I did not seek advice on influenza before going on my last business trip because. . . (multiple answers possible) . . .at my destination the risk of getting influenza 174 (29.7%) was low. . . .I did not think of influenza before departure. 377 (64.3%) . . .the time before departure was too short. 17 (2.9%) . . .I know the influenza situation there from a 24 (4.1%) prior trip. . . .I do not believe that influenza can be a 54 (9.2%) serious illness. Other∗ 92 (15.7%) No answer is correct. I did inform myself. 53 No response 22 Did you take any measures to prevent influenza on your last business trip? (multiple answers possible) Annual flu injection 179 (27.2%) Carriage of antivirals 38 (5.8%) Hand hygiene 103 (15.7%) Mask 0 (0.0%) Daily vitamins 62 (9.4%) Other 32 (4.9%) No measures 381 (58.0%) No response 4 Did you have antiviral tablets with you on your last business trip? Yes 64 (9.7%) No 597 (90.3%) How long did you wait before taking the antiviral medication? (only answered by the travelers who carried antiviral medication on their last business trip) I started taking them before any 10 (15.9%) symptoms occured. I started taking them within 2 days of 36 (57.1%) illness onset. I started taking them on the third day of 0 (0.0%) illness onset or later. I didn’t use the antiviral medication 17 (27.0%) although I had some with me. No response 1 For how long did you take the antiviral medication? (only answered by the travelers who used antiviral medication on their last business trip) Less than 5 d 32 (69.6%) 5–9 d 13 (28.3%)
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Influenza and the Use of Antiviral Medication in Business Travelers Table 4
Continued
More than 10 d 1 (2.2%) No response 1 Why did you take the antiviral medication? (multiple answers possible, only answered by the travelers who used antiviral medication on their last business trip) To reduce the risk of getting influenza 16 (34.8%) To reduce the duration of illness 37 (80.4%) It was recommended 2 (4.3%) Other 1 (2.2%) No response 1 I did not take any antiviral tablets along, because. . . (multiple answers possible, only answered by the travelers who did not use antiviral medication on their last business trip) My stay was very short 177 (29.7%) I do not like to use too many chemicals 222 (37.2%) I have read about severe side effects 10 (1.7%) I have experienced severe side effects 4 (0.7%) Taking the tablets is a nuisance 17 (2.9%) I could have reached a doctor in 82 (13.8%) Switzerland I could have reached a local doctor 246 (41.3%) There was no risk of influenza 95 (15.9%) No antivirals were recommended 136 (22.8%) I am concerned about resistances 58 (9.7%) Other 176 (29.5%) No response 19 ∗ Among
the 92 respondents who added an individual comment to this question, 22 declared to be vaccinated against influenza, 21 stated they were healthy and not part of a high-risk group, 11 thought it was not relevant to inform themselves about influenza, 8 responded they were already informed before their last business trip, and 6 answered that there was no higher risk of getting influenza abroad compared to Switzerland. The remaining 24 answers were not further specified.
58.0% (n = 381) did not take any measures to prevent influenza on their last trip. This shows that preventive measures should reach a greater part of the population. The Centers for Disease Control and Prevention (CDC), the WHO, and the National Travel Health Network and Centre (NaTHNaC) have guidelines on influenza vaccination and/or influenza prevention for travelers, but it can be difficult for a traveler to access Table 5
concise information on certain themes such as who should use antivirals and when they should be used. The above-mentioned travel health authorities have different recomendations (Table 5).17 – 19 This shows that consensus for concise advice regarding the travelers’ influenza prevention is needed. The issue of vaccine formulations for each hemisphere is an important topic. Influenza vaccine formulations are updated yearly according to virus surveillance information from each hemisphere. Vaccines prepared for use in the northern hemisphere typically are administered to travelers to the southern hemisphere, even when the vaccine formulation is less than optimal, because influenza vaccines prepared for use in the southern hemisphere are not available in Europe or in the United States. Health-care providers should ask patients about upcoming travel plans, inform them regarding the risk for influenza during travel, and be aware that vaccination of travelers with the currently available northern hemisphere influenza vaccine may not be the ideal vaccine formulation for the southern hemisphere. If possible, influenza vaccine should be administered to travelers a minimum of 2 weeks before departure, but can be administered up to the date of travel. No information is available regarding the benefits of revaccinating persons before summer travel who already were vaccinated during the preceding fall.20 The prevention of influenza using antiviral medication prophylactically is a neglected topic in travel health advice (Table 5). Influenza can be treated symptomatically, but another option is the use of antiviral medication. The three currently licensed Swiss antiviral agents are the two neuraminidase inhibitors oseltamivir and zanamivir, which are effective against both influenza A and B viruses, and amantadine which blocks the M2-protein and is only effective against the influenza A viruses (Table 6). The CDC recommends prescription of the neuraminidase inhibitors if antiviral treatment is indicated. During the 2007 to 2008 influenza season, oseltamivir resistance among influenza A
Guidelines on influenza prevention for travelers
Centers for Disease Control and Prevention
World Health Organization
National Travel Health Network and Centre
Recomendations for influenza vaccination
Recommendations for prophylactic use of antivirals
Recommends the vaccination for travelers when vaccination is available and if there are no contraindications, recommends annual vaccination of persons at high risk for complications [of the disease] Recommends the vaccination for travelers before the start of the influenza season, travelers who travel to the opposite hemisphere during the influenza season are at special risk Recommends the vaccination for all travelers at risk of complications of influenza, considers vaccination for healthy individuals traveling to the tropical and the subtropical regions
No recommendations
Recommended for travelers in the high-risk groups who have not been or cannot be vaccinated
Not usually recommended for travelers, may be considered [for] ‘‘at risk’’ groups
J Travel Med 2010; 17: 367–373
372 Table 6 travelers
Helfenberger et al.
Prophylaxis
Treatment
Comment
75 mg once daily for 10 d, max. 6 wk 10 mg once daily for 10 d, max. 1 mo 100 mg twice daily during risk peroid (usually about 6 wk)
75 mg twice daily for 5 d
Lower dose in renal failure
Burckhardt, DKSH, EcoSolidar, Georg Fischer, Gurit, Hapimag, HEKS, Helvetas, Implenia, Kabelwerke Brugg, Kuehne und Nagel, Kuoni Reisen, Metrohm, Meyer Burger, Micronas, OC Oerlikon, Pfister, Quadrant, Roland Berger, Schubarth und Co, Sika, Swisscontact, Synthes, and TUI Suisse.
10 mg twice daily for 5 d
Oral inhalative application
Declaration of Interests
100 mg twice daily for 4–5 d
Lower dose in elderly people and in renal failure
Antivirals used against influenza by business
Medication Tamiflu (oseltamivir) Relenza (zanamivir) Symmetrel (amantadine)
Research funds were obtained for vaccine studies from GSK and Novartis by C. H. and P. S. The other authors state they have no conflicts of interest to declare. References
(H1N1) viruses increased significantly for the first time worldwide,21,22 but zanamivir resistances were also detected in the years 2006 to 2008 in Australasia and Southeast Asia,23 and a dramatic increase of amantadine resistances was identifiable in 2005 to 2006.24 This resistance pattern does not refer to the 2009 influenza A (H1N1) pandemic strain. The use of amantadine is not recommended by the CDC until susceptibility to this antiviral medication has been reestablished. Over time, influenza viruses will probably develop resistance to any single antiviral agent. Treatment with several compounds that act at different stages of the viral life cycle would be more effective and make it less likely that any single mutation could confer resistance. This strategy may become feasible as new agents become available.25 The pros and cons of the self-use of antivirals by travelers has never been addressed in detail and international debate, and consensus is needed to formulate new guidelines for travel health considering the high risk of influenza-like illness in travelers. Conclusions and Public Health Implications Business travelers are not adequately prepared for the prevention and self-treatment of travel-associated influenza but they do have a good knowledge about the transmission and symptoms of the infection. International consensus and evidence-based guidelines are needed that concisely address indications and hemisphere appropriate composition of influenza vaccines and the carriage and use of antiviral medication by travelers. Acknowledgements We thank the business travelers for their generous participation and are grateful for the questionnaire distribution through the following companies, organizations, and travel medicine specialists: Nestl´e, Swiss International Airlines, University of Zurich, Swiss Tropical Institute, Berna Biotech, Bibus, Bundesreisezentrale Schweiz, Chemolio, Christoph J Travel Med 2010; 17: 367–373
1. European Centre for Disease Prevention and Control (ECDC). 2009. Available at www.ecdc.eu. (Accessed 2009 Dec 10) 2. Marti F, Steffen R, Mutsch M. Influenza vaccine: a travelers’ vaccine? Expert Rev Vaccines 2008; 7:679–687. 3. Mutsch M, Tavernini M, Marx A, et al. Influenza virus infection in travelers to tropical and subtropical countries. Clin Infect Dis 2005; 40:1282–1287. 4. Nitsch-Osuch A. Influenza as a health problem of sea travelers. Int Marit Health 2008; 59:103–112. 5. Mukherjee P, Lim PL, Chow A, et al. Epidemiology of travel-associated pandemic (H1N1) 2009 infection in 116 patients, Singapore. Emerg Infect Dis 2010; 16:21–26. 6. Wagner BG, Coburn BJ, Blower S. Calculating the potential for within-flight transmission of influenza A (H1N1). BMC Med 2009; 7:81. 7. Wilson ME, Weld LH, Boggild A, et al. Fever in returned travelers: results from the GeoSentinel Surveillance Network. Clin Infect Dis 2007; 44:1560–1568. 8. Luna LK, Panning M, Grywna K, et al. Spectrum of viruses and atypical bacteria in intercontinental air travelers with symptoms of acute respiratory infection. J Infect Dis 2007; 195:675–679. 9. Reichert T, Chowell G, Nishiura H, et al. Does glycosylation as a modifier of original antigenic sin explain the case age distribution and unusual toxicity in pandemic novel H1N1 influenza? BMC Infect Dis 2010; 10:5. 10. Freedman DO, Leder K. Influenza: changing approaches to prevention and treatment in travelers. J Travel Med 2005; 12:36–44. 11. Leder K, Sundararajan V, Weld L, et al. Respiratory tract infection in travelers: a review of the GeoSentinel Surveillance Network. Clin Infect Dis 2003; 36:399–406. 12. Ansart S, Caumes E. Influenza and travelling. Med Mal Infect 2006; 36:190–195. 13. Boggild AK, Castelli F, Gautret P, et al. Vaccine preventable diseases in returned international travelers: results from the GeoSentinel Surveillance Network. Vaccine 2010. doi:10.1016/j.vaccine.2010.09.009 14. Hsu CI, Shih HH. Transmission and control of an emerging influenza pandemic in a small-world airline network. Accid Anal Prev 2010; 42:93–100. 15. World Health Organization. WHO regional offices. 2010. Available at: http://www.who.int/about/regions/en/index. html. (Accessed 2010 Jul 07) 16. Petersen JE. Traveller’s medicine on the internet. Ugeskr Laeger 2005; 167:3971–3973. (Article in Danish)
Influenza and the Use of Antiviral Medication in Business Travelers 17. Centers for Disease Control and Prevention (CDC). Travelers’ health—yellow book. 2010. Available at http://www. nc.cdc.gov./travel/yellowbook/2010/chapter-2/influenzaseasonal-avian-pandemic.aspx. (Accessed 2010 Jan 26) 18. World Health Organization (WHO). International travel and health. 2009. Infectious diseases of potential risk for travelers. Available at http://www.who.int/ith/en/. (Accessed 2010 Jan 26) 19. National Travel Health Network and Centre (NaTH NaC). Travel health information sheets. Seasonal influenza. 2008. Available at: http://www.nathnac.org/ pro/factsheets/seasonalflu.htm. (Accessed 2010 Jan 26) 20. Centers for Disease Control and Prevention (CDC). Use of northern hemisphere influenza vaccines by travelers to the southern hemisphere. MMWR Morb Mortal Wkly Rep 2009; 58:312.
373 21. Ciancio BC, Meerhoff TJ, Kramarz P, et al. Oseltamivirresistant influenza A(H1N1) viruses detected in Europe during season 2007–8 had epidemiologic and clinical characteristics similar to co-circulating susceptible A(H1N1) viruses. Euro Surveill 2009; 14:pii=19412. 22. Dharan NJ, Gubareva LV, Meyer JJ, et al. Infections with oseltamivir-resistant influenza A (H1N1) virus in the United States. JAMA 2009; 301:1034–1041. 23. Hurt AC, Holien JK, Parker M, et al. Zanamivirresistant influenza viruses with a novel neuraminidase mutation. J Virol 2009; 83:10366–10373. 24. Weinstock DM, Zuccotti G. The evolution of influenza resistance and treatment. JAMA 2009; 301:1066–1069. 25. Moscona A. Global transmission of oseltamivir-resistant influenza. N Engl J Med 2009; 360:953–956.
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