Travel Vaccines & Yellow Fever

By: CHARLES N. CHUNGE MB ChB MSc, CNM, PhD, MSc, DLSHTM, FRCPS(Glasg)

Consultant Microbiologist, & Specialist in Tropical & Travel Medicine.

Director of the Centre for Tropical &Travel Medicine – Nairobi, Kenya.

MAIN OBJECTIVE TODAY

To make you medical people aware that excellent vaccines are available to prevent many serious/deadly diseases, so that you will take appropriate action to protect yourself & others.

What your objectives should not be!!

• To sleep here (This is not Parliament)

• To get to the TEA BREAK area very fast before others.

• To stare at other guests• To ask political questions• To sit next to her/him

A TRAVELLER IS A PERSON WHO:(Yes/No)

GOES ON SAFARI IS A TOURIST EATS IN A RESTAURANT OR

HOTEL TRAVELS OVERSEAS CATCHES A BUS, AEROPLANE,

TRAIN etc? INGESTS FOOD PREPARED

OUTSIDE HIS HOME

Which are the common diseases that afflict travellers?• Yellow Fever• AIDS?• Cholera• Travellers Diarrhoea• Hepatitis A• Hepatitis B• Influenza = Flu• Japanese encephalitis• Malaria?• Measles/Mumps/Rubella*

• Meningitis• Pneumonia• Rabies• Diphtheria• Tetanus• Polio• Tuberculosis• Typhoid fever• Cancer of CERVIX• Food-poisoning

As you can see from this list of diseases:

• Many of these diseases can be prevented by vaccines.

• Many cannot be cured easily.

• With the increase in travel, serious diseases are literally only a plane-ride away.

Vulnerable groups• Infants, because their immune systems cannot

easily fight off disease.• Children & workers in crowded situations• The Immuno-depressed/compromised• Those pregnant • Malnourished individuals• Old people (? Over 65yrs)• Professional groups (medical, military, students,

nurseries, orphanages, prisoners)• All Travellers

CHRONIC CONDITIONS WORSENED BY FAILURE TO VACCINATE

• HEART DISEASES• LUNG DISEASES• LIVER DISEASES• KIDNEY DISEASES• MENTAL DISEASES - ? Where? Kisii?• JOINT DISEASES• DIABETES, HIV, etc

Available Vaccines for travellers• Yellow Fever – Mandatory• Meningitis – sometimes mandatory (during Hajj)• Diphtheria-Tetanus (dT)• Typhoid, Travellers diarrh, Cholera,• Hepatitis A• Hepatitis B• Rabies• Polio• Measles-Mumps-Rubella• Influenza• Pneumococcal• Japanese encephalitis• Human Papilloma Virus (Cervical cancer)• Tuberculosis*** Malaria****HIV****

TRAVEL VACCINES: Classification Divided into 3 categories:• Mandatory (M): International Certificate required

– Yellow fever vaccine• Recommended (R) for all travellers to certain

countries– Meningo ACYW135 (Saudia Arabia) for Hajj

travellers– dTPolio to North and South America

• Recommended (r) for travellers to certain areas– Influenza and Pneumococcal vaccines for at

risk subjects: >65 yrs– Varicella for travellers to USA who do not

have antibodies– Rabies in Latin America

Vaccines for healthcare workers

• Hepatitis B • Influenza vaccine (annually for the flu) • Measles-Mumps-Rubella (MMR) vaccine

  • Varicella (chickenpox) vaccine • Typhoid• Meningitis

Vaccines for StudentsRecommended or Mandatory (depending on

who?) dT-Polio (diphtheriaTetanusPolio) Pneumococcal, Flu, Meningitis Hepatitis A Hepatitis B Measles,mumps,Rubella(MMR)-Susceptible/

without antibodies Varicella (chicken pox) Typhoid ETEC travellers diarrhoea & Cholera

There are no vaccines for:

Malaria (current efficacy =35-45%)

HIV (current efficacy <31%) Rift Valley Fever Bird Flu = Avian influenza Gonorrhoea or Syphilis Swine Flu H1N1 – remarkable efforts Anthrax Most STIs

The Value of Vaccination

Produces two Types of Protection OR Immunity among clients:

-Individual immunity

-Community Immunity

(Herd Immunity) !

Impact of vaccination: Benefits1. Immunisation saves 3Million lives/year

(WHO)2. Immunisation is second to provision

of clean water and third are antibiotics in saving lives

3. In addition to preventing disease, it reduces mortality, morbidity and medical/travel costs

4. It costs less than treatment5. It is easily explained

Impact of vaccination:Successful eradication• Smallpox was eradicated 1978

Vaccination costs less than treatment (this is excellent for a traveller)

For example typhoid:

Vaccine Ksh 500-1000 every 3 years

Treatment of disease Ksh >12000 twice a year?

Man hrs lost on off duties

School HRS lost on absenteeism

Cost of death = is too large to calculate

The Wise choice• Choosing to avoid vaccines is simply a choice

to take a different risk – usually much worse: =>the disease & its complications.

e.g. meningitis, pneumonia, Yellow fever, paralysis, deafness caused by mumps, liver cancer (by hepatitis B virus), heart failure, kidney failure, peritonitis (typhoid) and of course DEATH.

Therefore: When you compare the side effects/benefits of vaccines and the risk of the actual diseases, vaccines are the safer choice."

WHICH DOCTORS ARE LIKELY TO ADVISE PATIENTS ON PREVENTIVE MEASURES?

• PAEDIATRICIANS&Travel Medicine Specialists

• PUBLIC HEALTH SPECIALISTS• GYNAECOLOGISTS• PHYSICIANS & General Practitioners• DERMATOLOGISTS• SURGEONSWhy these differences?

Who consults prior to travel? (In descending order)

»AMERICANS»JAPANESE= very nice people

»GERMANS & FRENCH»SCANDINAVIANS»OTHER EUROPEANS»THE BRITISH »INDIANS,CHINESE

RUSSIANS, AFRICANS etc

What about Kenyans?

• Kenyan people and medical insurance companies want to treat the illnesses once it occurs; they tend to react only when a crisis occurs.

• They always try to skip mandatory vaccines (even doctors!)

• We need to teach them the truth: “Prevention is better than cure”

Yellow Fever

Yellow and feverish

He is Yellow

Yellow Fever• Why the name?• The arbovirus is called Flavivirus • The vector: Aedes, Haemagogus

mosquitoes

• Prevalence = Variable (Africa & Americas)

• India & Asia/Far East = Nil (but very

suitable) • A zoonosis = Primates reservoirs

Yellow Fever• Endemic areas: Africa and C.&S.

America• Urban YF seen in South America• Sub clinical cases may occur = 15%• Kills over 60-80% of its victims • Why is it the only compulsory

vaccine?Because: The vectors, the primates & humans exist in Asia

But the disease does not.

VEGETATION MAP OF AFRICA

Yellow fever belt

JUNGLE TYPE YELLOW FEVER• This enzootic cycle is essentially animal and

keeps the virus alive in the tropical forest of Africa and South America

• In Africa, Monkeys do not die once infected, they become and remain immune.

• Monkeys don’t act as virus hosts, as their viremia is short but rather as amplifiers & indicators of virus circulation

• Transovarial transmission in the mosquito keeps the virus alive

EPIDEMIC YELLOW FEVER

• Transmission from man to man => epidemic

• Main vector : Aedes Aegypti

Aedes aegypti

Yellow Fever

Yellow Fever

DIAGNOSIS / TREATMENT• Incubation period: lasts 3 to 6 days• Evolution :

-Acute forms are fatal in 2-7 days,

-Severe forms are fatal > 80% of cases.

-Milder forms similar to flu-like syndrome or viral hepatitis.

Mortality: Upto 80 % despite treatment

Diagnosis: Serology

Yellow Fever: TREATMENT• There is no specific anti-viral Yellow fever

therapy

• The mortality rate for acute forms of the disease is 80%, despite any treatment

• The only efficient prevention is the routine vaccination of all persons exposed to the disease risk

• Vaccination for international travellers is aimed at preventing travellers from getting infected abroad and taking the disease back home.

Side effects: Viscerotropic and Neurotropic Disease

Age >60 years •Risk of Viscerotropic Disease:

≈ 20/106 or 1/50,000• Risk of Neurotropic Disease:

≈ 15/106 or 1/65,000

VACCINE EXEMPTIONS allowed: ESPECIALLY IN THOSE >65YRS

Where to go for the vaccination

Vaccination Centres Travel Health clinics Hospitals Medical Clinics (with enlightened

providers)

? Pharmacies Airports/entry/exit points

LASTLY:Do not get involved with any of the following attractions

GOING TO MECCA TO WORSHIP Allah using fake vaccine certificates

“MY BOOKLET IS LOST SYNDROME” (ladies)

ACQUIRING/issuing of FAKE BOOKS & STAMPS

COMING LATE FOR VACCINATION! Then demanding a backdating.