Vaccines for Enterically Transmitted Diseases
Download
1 / 43

Vaccines for Enterically Transmitted Diseases in travelers - PowerPoint PPT Presentation


  • 116 Views
  • Uploaded on

Vaccines for Enterically Transmitted Diseases in travelers. Prof. Eli Schwartz MD,DTMH The Center of Geographic Medicine & Tropical Diseases Sheba Medical Center, Tel-Hashomer Sackler Faculty of Medicine, Tel-Aviv univ. ISRAEL. Typhoid: Global Epidemiology. Typhoid: Global Epidemiology.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Vaccines for Enterically Transmitted Diseases in travelers' - elvina


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
Diapositive 1

Vaccines for Enterically Transmitted Diseases

in travelers

Prof. Eli Schwartz MD,DTMH The Center of Geographic Medicine & Tropical Diseases Sheba Medical Center, Tel-HashomerSackler Faculty of Medicine, Tel-Aviv univ. ISRAEL



Diapositive 1

Typhoid: Global Epidemiology

  • 33 Million cases annually

  • 600,000 deaths

  • Incidence rates

  • low: <1/105 population in developed countries

  • high: >800/105 population in endemic areas


Diapositive 1

Typhoid: Global Epidemiology

  • Greatest burden of disease in ASIA

    • 13 million cases per year

    • 400,000 deaths annually

    • incidence rates as high as 900-1200/105

    • rise in cases since 1990s


Diapositive 1

Annual incidence of Typhoid Fever

worldwide

Conor BA, Schwartz E.Typhoid and paratyphoid fever in travelers. Lancet Infect Dis. 2005;5:623-8


Diapositive 1

Typhoid Epidemiology

in Developed Countries


Diapositive 1

Typhoid Epidemiology

in Developed Countries

Now a travel associated disease

in industrialized countries


Diapositive 1

Incidence of Typhoid Fever (Lt)

and % of travelers (Rt)-USA

8

100

90

7

80

6

70

5

60

% travelers

4

50

USA: incidence/100,000

40

3

30

2

20

1

10

0

0

1940

1945

1950

1955

1960

1965

1970

1975

1980

1985

1990

1995

2000

USA: incidence/100,000

% travelers

Connor BA, Schwartz E. Typhoid and paratyphoid fever in travelers.Lancet Infect Dis. 2005;5:623-8.


Diapositive 1

Risk Factors

Travel to rural areas with poor sanitation

Not following food and water precautions

Not receiving pre-travel consultation

Length of stay

VFR’s


Diapositive 1

The pathogens

Enteric fever, the more inclusive term, is caused by

Salmonella enterica serotypes S. typhi and S. paratyphi.

S. Typhi

S. paratyphi A

S. paratyphi B

S. paratyphi C


Diapositive 1

The bacteria

Geographic distribution

S. typhi

Developing countries, manily the Indian subcontinent and South-East Asia

S. paratyphi A

Indian subcontinent

S. paratyphi B

Indonesia, Malaysia, the Mediterraneanregion and South America

S. paratyphi C

Africa

Enteric Fever pathogens

&

Geographic distribution


Diapositive 1

Rate of infection : S.Typhi vs S.paratyphi

Schwarts E. et al, Arch Intern Med 150; 349-351, 1990


Diapositive 1

Annual cases of S. typhi and S.paratyphi in the UK

http://www.hpa.org.uk/infections/topics_az/salmonella/data_typh.htm



Diapositive 1

Typhoid Prevention

“Boil it, Cook it, Peel it or Forget it “

Easy to remember,impossible to do!



Typhoid vaccines
Typhoid vaccines

Parenteral vaccines (anti Vi):

  • circulating antibody response

    Live attenuated oral vaccines(Ty21a):

  • vigorous secretory IgA response

  • cell mediated response


Meta analysis of typhoid vaccine efficacy
Meta-analysis of typhoid vaccine efficacy

Engels EA, et al. Typhoid fever vaccines: a meta-analysis of studies on efficacy and toxicity. BMJ 1998; 316: 110–16



Typhoid vaccine
Typhoid Vaccine

Efficacy 60-70%


Vi conjucated vaccine repa nontoxic recombinant pseudomonas aeruginosa exotoxin a
Vi-Conjucated Vaccine (rEPA)[nontoxic recombinant Pseudomonas aeruginosa exotoxin A]

Highly immunogenic

Cumulative efficacy ~ 90%

Long term immunity

Probably immungenic in Infants <2 y.

Lanh, M. N. et al ; N. Engl. J. Med. 349:1390-1391


Typhoid vaccine1
Typhoid Vaccine

Efficacy 60-70%

All studies done in endemic areas among local population

What it does mean for Travelers ?


Typhoid vaccine2
Typhoid Vaccine

Immunity :

relative and can be overcome

immunity can be overcome if large infecting dose is ingested

protective effect of prior clinical infection only 28%


Differences between traveler and indigenous population

Traveler:

no pre-existing immunity

Try to avoid contaminated food and water

More rapid and available access to medical care

Differences between traveler and indigenous population

  • Indigenous population:

    • Constant boosting

    • Live in the same condition

    • more severe clinical course


Typhoid risk to the traveler
Typhoid: risk to the traveler

  • CIWEC Clinic, Kathmandu

  • Risk of acquiring enteric fever:

  • vaccinated : 12/105

  • unvaccinated: 217/105

Schwartz E. et al, Arch Intern Med 150; 349-351, 1990


Diapositive 1

Meltzer E., Sadik C, Schwartz E. Enteric Fever in Israeli Travelers: a Nation-Wide study. J. of Travel Medicine 2005;12:275-81


Diapositive 1

Typhoid Vaccine: conclusions

Vi vaccine- better protection for S.typhi

Ty21a vaccine-better protection for S.paratyphi A

Their mode of action is different, mucosal vs. humoral immunity

Should we recommend a sequential immunization: Vi vaccines and Ty21a?!


Conclusions
Conclusions

Typhoid vaccine is an important tool to protect travelers

A more effective Typhoid vaccine is needed

It should includes a Paratyphi A coverage as well.


Diapositive 1

Typhoid Vaccine: conclusions

  • Typhoid fever remains a major health problem for travelers. All travelers to endemic areas are at potential risk.

  • Increasing antimicrobial resistance has made preventive strategies even more essential.

  • Typhoid fever vaccination may be offered to travelers to destinations where the risk of typhoid fever is high, and/or in locations where antibiotic-resistant strains of S. Typhi are prevalent.

  • Vi and the Ty21a vaccines provide appreciable levels of protection and have a good record of safety.


Hepatitis a

Hepatitis A

One of the World’s Most Common Infectious Diseases


Geographic distribution of hepatitis a
Geographic Distributionof Hepatitis A

Ref: Centers for Disease Control and Prevention MMWR 48(RR-12), 1999




Hav seroprevalence in israel
HAV Seroprevalence in Israel

100

94

80

80

60

Prevalence %

55

46

40

20

0

1977

1987

1989

1995

2000

Year


Prevalence of hav igg in israeli travelers
Prevalence of HAV IgG in Israeli Travelers

82

76

68

HAV-IgG Positive

33

24

Age Group (years)

Schwartz E. & Raveh D. ; Int J Epidem 27:118-120, 1998



Passive immunization
Passive Immunization Group

  • Short-term protection – requires frequent renewal

  • No stimulation of antibody production in recipient

  • Serum–derived product

  • Large injection volumes


Active vaccination
Active Vaccination Group

  • Long-term protection from single course of vaccination

  • Stimulates antibody production in the recipient

  • Non serum-derived product

  • Small injection volumes


Hav antibody titres in persons with active passive immunization after hav infection
HAV Antibody Titres in Persons with Active & Passive Immunization & After HAV Infection

Natural

infection

Vaccinated persons

Anti-HAV GMT mIU/ml

Passive immunization


Havrix hepatitis a vaccine seroconversion rates
Havrix Immunization & After HAV Infection Hepatitis A Vaccine Seroconversion Rates

Injections given at months 0 & 1 with a booster at 6 months


Hepatitis a combined vaccines
Hepatitis A –combined vaccines Immunization & After HAV Infection

  • Hepatitis A+ Typhoid Fever

    -Hepatirix – GlaxoSmithKline, Viatim-Sanofi Pasteur

  • Hepatitis A +B

    - Twinrix – GlaxoSmithKline


Diapositive 1

Be careful! Immunization & After HAV Infection

Thank you !