Travel to many areas of the world may expose the traveller to potentially fatal infectious diseases, some of which could be prevented by vaccination. Diseases such as diphtheria, meningococcal meningitis, and yellow fever are re-emerging as public health issues due to demographic, social and ecological changes. These changes are in part due to the dramatic increase in international travel.¹

This accelerating and extensive population flow increases the threat of transmission of infectious disease and gives rise to a corresponding public health problem. An outbreak of disease anywhere in the world must be identified and considered a threat to travellers and to the countries and communities they return to.¹

 

 

In a survey carried out in 1999, only about half of at-risk UK travellers claimed they were protected against some of the diseases they might encounter whilst travelling.²

Of major concern was the fact that 67% of travellers to areas of high or medium risk for infectious diseases had not even taken medical advice before travelling. Around 51% admitted that they had not been vaccinated against relevant diseases for their last trip to a medium or high risk area.²

This is even more surprising since current Department of Health (DoH) policy allows doctors to provide certain vaccines at no charge to their NHS patients specifically, these would be vaccines which protect against those diseases which could pose a public health risk if imported into the UK, such as hepatitis A and typhoid fever.

 

The major vaccine preventable diseases may be transmitted by various routes:

• Hepatitis A or typhoid fever can be contracted through consumption of contaminated food and drink.
• Biting insects such as mosquitoes and ticks can transmit yellow fever and various forms of encephalitis.
• Hepatitis B can be contracted through treatment with unsafe medical equipment or other transmission of bodily fluid.
• Close physical contact and overcrowding can lead to the transmission of meningococcal meningitis and diphtheria by saliva droplets.

 

 

Many travellers believe that they can be vaccinated just days before travel but in reality, travellers should seek travel health advice at least one month before their trip. Some vaccines cannot be given together and some need more than one dose. In addition, all vaccines need time for protection to develop in your body. The travel health consultation is also an opportunity to advise the potential traveller about other diseases which cannot be prevented by vaccination.

The regular business traveller to areas of the world where vaccine-preventable diseases are common should maintain vaccination coverage against these infectious diseases on a continuing basis.

 

 

Information regarding the vaccines recommended for travellers can be found in the Department of Health book, "Health Information for Overseas Travel", also known as the Yellow Book.³

The range of vaccines needed by the traveller depends on the countries visited, the activities planned, where the traveller is staying and how long the visit will last. There are only two vaccines which are compulsory for entry into certain countries - yellow fever if entering or arriving from an area where yellow fever is endemic and meningococcal meningitis if attending the Muslim religious festival, the Hajj or Umrah, in Mecca, Saudi Arabia.

Vaccines such as those protecting against hepatitis A, typhoid, polio, and tetanus may be recommended, whilst other vaccines, including diphtheria, rabies and hepatitis B should be considered depending on the level of potential risk. Ask your practice nurse or GP for specific advice on requirements for your chosen destination.

 

 

HEPATITIS A

Hepatitis A is a viral disease which is easily transmitted through consuming contaminated food or drink. The disease is the most common vaccine-preventable disease among unprotected travellers ⁴ and the risk to the unprotected individual is thought to be between 1 in 300 and 1 in 500. ⁵ The areas of highest risk are Africa, Asia, South and Central America but the vaccine is also recommended for travellers to Turkey and some Eastern European countries. The risk is greater for those travellers who travel outside the usual tourist routes and eat or drink under conditions of poor hygiene. Despite this, hepatitis A can also be caught in expensive hotels. Previously infected travellers are likely to be immune and do not need to be vaccinated.

It is recommended that vaccination is given at least two weeks before departure although it can be given up to the day of departure.⁶

MENINGOCOCCAL MENINGITIS

Meningococcal meningitis is caused by a bacterium called Neisseria meningitidis and is most prevalent in the sub-Saharan countries of Africa during the dry season, Nepal, Bhutan and Saudi Arabia. For the last few years, all pilgrims travelling to the Hajj and Umrah in Mecca have been asked to provide a vaccination certificate.

POLIOMYELITIS (polio)

The risk of polio is low to the average international traveller - less than 1 in 1,000,000.⁵ This viral disease is spread through faeces and saliva or through close contact with an infected person.

TETANUS

Tetanus is caused by a poison (toxin) produced by the bacterium Clostridium tetani and is found in every country in the world. The disease is caused when the bacteria enter the body through a deep wound. Everyone should be protected against tetanus whether they are travelling abroad or not.

DIPHTHERIA

Diphtheria is caused by a poison (toxin) produced by a bacterium called Corynebacterium diphtheriae. The disease is spread through infected droplets of saliva. Recent outbreaks of diphtheria have occurred in Eastern Europe. The main regions where diphtheria currently occurs are Russia and several other states of the former Soviet Union but the disease is also common in Africa and Asia. Everyone should be protected against diptheria whether travelling abroad or not.

TYPHOID FEVER

The risk of typhoid fever is thought to be in the region of 1 in 3,000 for the unprotected international traveller in India, Senegal and North Africa where typhoid fever is endemic, and ten times lower in other countries where typhoid is common.⁵ The disease is spread by contaminated food and drink. Every year between 100-200 cases of typhoid are imported into the UK by unvaccinated travellers.

YELLOW FEVER

Yellow fever is a viral disease which is transmitted through the bite of an infected mosquito. It occurs in the Yellow Fever Zone, which includes countries in tropical Africa and South America. Yellow fever infection is very dangerous, causing death in more than 50% of patients.⁶ For some countries in Africa and South America, a certificate of vaccination against yellow fever is mandatory for entry into the country, while other countries demand a certificate if the traveller is arriving from a country where yellow fever is common.

 

 

HEPATITIS B

Hepatitis B is a viral disease which is spread through contact with blood and other infected bodily fluids. Transmission routes are similar to those for HIV although hepatitis B is considered to be 100 times more infectious than HIV.⁹ Hepatitis B is very common in some parts of the world such as Africa, South-East Asia and parts of South America, and may have fatal long-term complications. Medical or dental treatment in these areas is a risk and those who may require treatment, including frequent or longer-stay travellers, children and others visiting friends and relatives, people with chronic medical conditions, or those travelling for medical care should consider vaccination. Hepatitis B should also be considered for those that participate in activities that might put them at risk for medical or dental treatment, including sporting activities, travel to remote areas, or aid work. As accidents and illness are unpredictable, it is important to be aware of how the virus is transmitted, to take preparations such as sterile surgical kits, and as appropriate to be vaccinated. Hepatitis B can prove a risk to sexually promiscuous travellers. The standard full course of vaccine takes up to 6 months to complete, although there are accelerated courses available which allows for vaccination within a month. In either case, the traveller should consult their GP or travel clinic well in advance of the journey.

RABIES

Most travellers are unaware of the risk of rabies while they are abroad.
The disease is transmitted in the saliva of infected animals, usually through a bite - although licking alone can transmit rabies if there are skin abrasions. With the exception of one known case, rabies is invariably fatal if left untreated. The World Health Organisation estimates that there are between 35,000 and 50,000 deaths globally every year, with the largest number reported in India (30,000).¹⁰

JAPANESE ENCEPHALITIS

Japanese encephalitis is a viral disease transmitted through the bite of infected mosquitoes. It occurs in South East Asia and the Far East where it is endemic in rural areas. Highest transmission rates occur when mosquitoes are most active - during and just after wet seasons - though seasonal patterns vary within individual countries and from year to year. Immunisation is recommended for travellers staying for a month or longer in endemic areas, especially if travel involves rural areas.

TICK BORNE ENCEPHALITIS

This viral disease is spread by ticks which live in the forest areas of Northern and Central Europe and Scandinavia.

 

 

1. Alary JC. Travel-related health risks; a question of communication. J Travel Med; 4:105-6
   
2. IPSOS RSL Consumer Survey August 1999
   
3. Health Information for Overseas Travel. Ed Lea G and Leese J. HMSO 2001
   
4. Steffen R. Hepatitis A and hepatitis B: risks compared with other vaccine preventable diseases and immunisation recommendations. Vaccine 1993: 11 (suppl): 18-20
   
5. Reid D & Keystone J in Textbook of Travel Medicine and Health. B C Decker. 1997
   
6. Immunisation against Infectious Disease – “The Green Book”. Department of Health. 2006
   
7. WHO Poliomyelitis Factsheet.
   
8. Immunisation against infectious disease. Ed Salisbury D and Begg N. HMSO, 1996, p263
   
9. Action on hepatitis B as an occupational hazard. Viral Hepatitis Prevention Board. Hepatitis B: 10 facts at a glance
   
10. WHO Weekly Epidemiological Record, no 45. 12 November 1999