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Travel Medicine Scenarios

Travel Medicine Scenarios. Annelies Wilder-Smith Director, Travellers’ Screening and Vaccination Clinic, NUH Associate Professor, National University Singapore Editor for WHO Sept 06-Jan 07. Case Scenario I. A 25 year old male traveller was bitten by a dog in India.

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Travel Medicine Scenarios

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  1. Travel Medicine Scenarios Annelies Wilder-Smith Director, Travellers’ Screening and Vaccination Clinic, NUH Associate Professor, National University Singapore Editor for WHO Sept 06-Jan 07

  2. Case Scenario I • A 25 year old male traveller was bitten by a dog in India. • The first injection of rabies vaccine was given on the day of the bite. • now day 3 after the bite. • What advice do you give? What is the vaccination schedule? Would you offer human rabies immunglobulin?

  3. Post exposure prophylaxis

  4. QUESTION A TRAVELER WHO HAS HAD NO PRIOR RABIES IMMUNIZATION IS BITTEN BY A DOG IN NEPAL, BUT DOES NOT SEEK TREATMENT IN NEPAL. HE SEEKS MEDICAL ADVICE 2 WKS AFTER THE BITE. THE RECOMMENDED TREATMENT IS: a. 5 DOSES OF VACCINE(0,3,7,14,28) BUT NO RIG SINCE >7 DAYS SINCE BITE. b. HRIG ALONE (>7 DAYS SINCE BITE) c. NOTHING(>7 DAYS SINCE BITE, DOG WASN’T SICK) d. HRIG FOLLOWED BY 5 DOSES OF VACCINE (0,3,7,14,28)

  5. ANSWER d. HRIG FOLLOWED BY 5 DOSES OF VACCINE (0,3,7,14,28) • HRIG to be injected directly into wound, dilute w. saline if needed for multiple sites (Wilde). Large wounds-secondary suturing 7 days later. • HRIG - 20 units/kg total - do NOT give if person has had pre-exposure vaccine. If no visible wound, give IM (e.g. bat contact)

  6. RABIES (cont) RE THE 7 DAYS PART OF THE ? - GIVE THE HRIG/RIG ON DAY 0 AT FIRST VISIT – BUT NO MORE THAN 7 DAYS AFTER FIRST VACCINE SHOT - BECAUSE IT MAY SUPPRESS THE ENDOGENOUS AB RESPONSE. Wilde H, et al. Rabies update for travel medicine advisors. Clin. Infect. Dis. 2003 July 1;37:96-100.

  7. Case Scenario II • VFR traveler • 74 year-old Senegalese man who has lived in China for 30 years.  • He has not traveled back to Africa since coming to China. • He will be returning for a 6-week stay in Dakar and in a small village in the Casamance.  • He has no recollection of having received a yellow fever vaccine when living in Senegal.  • Would you recommend yellow fever vaccine?  • If his daughter (34 years old, who is trying to get pregnant again) and two grandchildren, ages 5 years old and 6 months old, take the trip with him, should they all be vaccinated against yellow fever?

  8. Yellow fever vaccination • 1) To prevent the international spread of the disease by protecting countries from the risk of importing or spreading the yellow fever virus. These are mandatory requirements established by the country. • 2) To protect individual travellers who may be exposed to yellow fever infection The fact that a country has no mandatory requirement for vaccination does not imply that there is no risk of yellow fever transmission.

  9. Yellow fever vaccine Live vaccine Serious adverse events

  10. Reporting Rates of YEL-AND and YEL-AVD by Age Group-USA Only YEL-AVD YEL-AVD YEL-AND YEL-AND Number of doses distributed (1000) Reported rate per 1,000,000 Age breakdown

  11. Germany - 1999 Belgium 2000 Tennessee - 1996 Switzerland - 1996 Texas - 2002 California - 1999

  12. POTENTIAL GLOBAL SPREAD OF URBAN YELLOW FEVER

  13. Yellow Fever

  14. IHR 2005 • The revised International Health Regulations (2005) entered into legal force on 15 June 2007 • The most significant change to the IHR (2005) has been to broaden their scope of application from three diseases (cholera, plague and yellow fever) to any event with the potential to be a public health emergency of international concern, including events that do not have an infectious etiology.

  15. Exposure risk versus vaccine risk • More accurate definition of risk • More appropriate targeting of vaccine • Avoidance of unnecessary adverse events

  16. Current WHO & CDC Africa YF Maps 2008 2008

  17. Current WHO & CDC South America YF Maps 2008 2008

  18. Limitations of Current YF Risk Map • Current YF risk map is best we have, but has limitations • Inaccurate • Outdated underlying surveys • Artificial • Follows country boundaries • Follows latitude lines • Periodic modifications • Rationale not well documented • Produces variations in accuracy

  19. Yellow Fever risk in Africa by second administrative division

  20. This is a draft version for the Yellow Fever Working group discussion only

  21. Case scenario III • Group of 15-16 year old to North Thailand • Anxious parents • What advice do you give?

  22. Immunise according to the risk of infection, not according to the country visitedRisks depend on length and mode of travel

  23. Incidence rate of various vaccine preventable diseases per month of stay for non-immune travelers visiting a developing country 2500 2000 2000 Morbidity per 100,000 travelers 1000 80 (Africa, Latin America) -240 (Asia) 300 200 30 3 0.3 0 Hepatitis A Hepatitis B Rabies risk Typhoid fever Cholera Tramper Hotel- tourist Expatriate India NW-Africa Peru other destinations (Animal bites in expat's)

  24. Vaccines: Routine vaccines Hepatitis A, B JE Rabies CDC recommends:

  25. Adapted from CDC 20083 JE: the most important viral encephalitis in Asia 1,2 • Approximately 3 billion people live in areas at risk of JE 1 • 30–50,000 cases of JE in Asian residents per year, leading to10–15,000 deaths1-3 • Travelers visiting the enzootic region are at risk of JE, but the risk is low. 4 • PATH. 2008. http://www.path.org/projects/JE_in_depth.php • World Health Organization. Japanese encephalitis vaccines. Wkly Epidemiol Rec 81[34/35], 331-340. 2006. • World Health Organization. Causes of death 2002. http://www.who.int/research/en/. 2004. • Centers for Disease Control and Protection. Travelers’ Health: Yellow Book. Chapter 4 – Japanese encephalitis. 2008.

  26. JE virus is transmitted in an enzootic cycle involving pigs and water birds 1 Other wild and domesticated animals may substitute as amplifying hosts 2 The transmission cycle traditionally takes place in rural areas; but can occur in ‘semi-rural’ areas, andeven cities 1 Humans are incidental to the transmission cycle 1 JE virus is transmitted in an enzootic cyclewhich is hard to avoid or eradicate Adapted from Halstead and Tsai 2004 1 • Halstead SB, Tsai T. Japanese Encephalitis Vaccines. In: Plotkin SA. Orenstein WA (Hrsg.): Vaccines. 4th edition. Saunders, 2004, S. 919-958. Chapter 33. • Ting SH et al. Acta Tropica 2004; 92: 187-191.

  27. Culex mosquito Preferred breeding habitat of C tritaeniorhynchus

  28. 4-7 5,6 JE viral infection can be devastating Summary of outcomes of JE • Between 1 in 300 and 1 in 1000 infections with JE virus lead to clinical disease 1-2 • Immunologically-naïve adults (e.g. travelers) have a similar risk of infection as children living in endemic areas 3 • JE is fatal in ~1 in 3 cases 4-7 • JE results in significant neurological sequelae in ~1 in 3 cases 5,6 Adapted from references 4-7 • Grossman RA et al. Am J Epidemiol 1973; 98: 133-149. • Southam CM. J Infect Dis 1956; 99: 163-169. • Umenai T et al. Bull World Health Organ 1985; 63: 625-631. • Burke DS et al. Am J Trop Med Hyg 1985; 34: 1203-1210. • Hoke CH et al. J Infect Dis 1992; 165: 631-637. • Schneider RJ et al. Southeast Asian J Trop Med Public Health 1974; 5: 560-568. • Simpson T & Meiklejohn G. Am J Trop Med Hyg 1947; 27: 727-731.

  29. JE is rare in travelers but can have devastating consequences IMPACT Meningococcal Disease Yellow Fever HighCFR>10% or Frequent Sequelae Poliomyelitis Vaccination Essential Japanese Encephalitis Hepatitis B Hepatitis A Tetanus Rabies (risk exposure) IntermediateCFR<10% and/or Sequelae Diphtheria Typhoid Fever Measles Influenza Cholera LowCFR<2% INCIDENCE Low0.1-0.9 Intermediate1-99 per 100,000 Very Low<0.1 High100 Impact and incidence of vaccine-preventable diseases in travelers to developing countries • Steffen R & Connor BA. J Travel Med 2005; 12: 26-35.

  30. Biken- mouse-brain derived JE vaccine • Allergic mucocutaneous reactions • 8% reacted 1-2 weeks after vaccination • Two third of the reactions are observed after the second dose (but also isolated cases after first dose) • Frequency is 6 per 10,000, but different batch numbers were involved with varying rates of reactions (1991!!) – true frequency 1 per 100,000 vaccinees • Anaphylactic shock with cardiovascular symptoms without cutaneous symptoms • Usually within 30 minutes after receiving JEV • Frequency is 2 per 1 million doses

  31. Biken- mouse-brain derived JE vaccine Allergic mucocutaneous reactions 8% reacted 1-2 weeks after vaccination Two third of the reactions are observed after the second dose (but also isolated cases after first dose) Frequency is 6 per 10,000, but different batch numbers were involved with varying rates of reactions (1991!!) – true frequency 1 per 100,000 vaccinees Anaphylactic shock with cardiovascular symptoms without cutaneous symptoms Usually within 30 minutes after receiving JEV Frequency is 2 per 1 million doses

  32. New vaccine againgst JE --- IXIARO: inactived Vero cell based vaccine

  33. Pivotal non-inferiority study of IXIARO compard with Biken-JE-VAX 1 • Observer-blinded, randomized, multicenter, multinational study • Primary aim: immunogenicity, assessed by plaque-reductionneutralization test (PRNT) at day 56 • Secondary aims: local and systemic tolerability Study design Day 0 Day 7 Day 28 Day 56 IXIARO Placebo IXIARO n=430 Immunogenicityassessment Adverse event diaries R* JE-VAX JE-VAX JE-VAX n=437 Adverse event diaries *R, randomization Adapted from Tauber et al. 2007 1 • Tauber E et al. Lancet 2007; 370: 1847-1853.

  34. IXIARO was shown to be highly immunogenic 1 • IXIARO provided protective antibodies* in up to 98% of subjects 1 • Two doses of IXIARO were non-inferior to three doses of JE-VAX • Geometric Mean Titer (GMT): 244 for IXIARO and 102 for JE-VAX JEV neutralizing antibody levels at day 56 Adapted from Tauber et al. 2007 1 • *A sero-protective threshold is defined as a PRNT titer of greater than 1:10. 2 • Tauber E et al. Lancet 2007; 370: 1847-1853. • Hombach J et al. Vaccine 2005; 23: 5205-5211.

  35. IXIARO demonstrated a statistically significantly better local tolerability profile than JE-VAX 1 Subjects with at least one severe local symptom 0–6 daysafter vaccination (on days 0 or 28) Fisher’s exact test for any symptom (9/421 [2%] vs 59/427 [14%]): P<0.0001 Adapted from Tauber et al. 2007 • Tauber E et al. Lancet 2007; 370: 1847-1853.

  36. IXIARO resulted in protective titers 7 days after the second dose 1 • IXIARO should be given as a two-dose schedule, on days 0 and 28 • 7 days after the second dose, 97.3% of subjects have protective immunity 1 • There is no requirement for a safety observation period following vaccination • Dubischar-Kastner K et al. Abstracts of the 57th American Society for Tropical Medicine and Hygiene annual meeting, New Orleans, LA, USA, December 7-11 2008

  37. IXIARO represents an advance in JE vaccines Comparison of IXIARO and mouse-brain-derived vaccines Adapted from Tauber et al. 20071 • Tauber E et al. Lancet 2007; 370: 1847-1853.

  38. Vaccination of travelers against JE – guidelines • Guidelines for vaccination of travelers were developed by the Advisory Committee on Immunization Practices (ACIP) in 1993 in response to the licensing of a mouse-brain-derived vaccine in the USA 1 • They were designed to minimize exposure to the vaccine due to reports of rare, serious adverse events following immunization 1 • Vaccination was recommended for: 1 • Other countries created similar national guidelines following this model 2,3 • Centers for Disease Control and Prevention. MMWR Morb Mortal Wkly Rep 1993; 42: (RR-1). • Department of Health UK. Green Book. Chapter 20. 2006. • Deutsche Gesellschaft für Tropenmedizin und Internationale Gesundheit http://www.dtg.org/j_enzephalitis.html. 2009

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