Vaccinations are an effective method to prevent many of the diseases that can be contracted when travelling. Before taking a trip, you should first check that you are up to date with the vaccinations provided for by the national plan, in particular those against diphtheria, tetanus, pertussis, poliomyelitis, hepatitis B, Haemophilus influenzae type B, pneumococcus, meningococcus, measles, mumps , rubella, chickenpox and flu. Depending on the destination, vaccines against specific diseases will be recommended (cholera, hepatitis A, typhoid fever, rabies, tick-borne encephalitis, Japanese encephalitis, yellow fever, meningococcal meningitis). Today the only certificates that are required for international travel, limited to certain destinations, are those against yellow fever, meningitis and poliomyelitis. As regards malaria, for each country located in the areas concerned, a specific one is recommended, based on the species and level of parasites present.
Despite their effectiveness at preventing illness, vaccines rarely give 100 percent protection. The vaccinated traveller should not assume that there is zero risk of contracting the disease against which he/she is vaccinated. All additional preventive measures against infections must therefore be strictly followed regardless of whether vaccines or other drugs have been administered1.
Detailed information on the mandatory or recommended vaccinations when visiting the different areas of the world and on the most appropriate preventive measures are provided by outpatient clinics for international travellers and can be found on numerous official websites, including that of the Italian Ministry of Health, of the World Health Organization (WHO), of the Region of Veneto.
Here are some hints on the main diseases that may affect the traveller and that can be prevented by vaccination2:
These still represent a significant health problem in many areas of the world today. Diphtheria is an acute bacterial disease, which is spread through airborne transmission, through contact with an infected person or a healthy carrier of the bacterium; it is very serious and can even lead to death. Tetanus is an acute disease, caused by a toxin produced by tetanus bacillus, which develops at the site of contaminated wounds or broken skin, however slight. It is characterised by painful muscle spasms. Regardless of destination and length of stay, travellers must be adequately protected against these diseases (scheduled and booster vaccinations).
Polio is an acute viral infection that affects the gastrointestinal tract and occasionally the central nervous system; it is contracted by ingesting contaminated water or food. Vaccination is recommended for travellers visiting countries which are experiencing disease outbreaks. Travellers who were not vaccinated in infancy, or who have not been completely vaccinated or whose vaccination status is unknown, will be given a complete cycle; to those who have already performed a primary cycle, a booster dose will be given.
Yellow fever is a very serious, often deadly disease caused by a virus spread by a mosquito that generally stings during daylight hours. The disease is present throughout equatorial Africa and in South America, where transmission can take place up to 2,500 meters above sea level. Its manifestation can range from mild flu-like forms to severe hepatitis and haemorrhagic fever. There is no specific therapy. The vaccine is very effective. Vaccination is mandatory in some countries; this list is periodically updated by the World Health Organization (WHO). Vaccination is, however, recommended to travellers visiting countries where the disease is present. It must be performed at least 10 days before departure and is long-lasting (over 10 years). The yellow fever vaccine is administered exclusively at centres authorised by the Italian Ministry of Health.
Typhoid fever is a serious infection, caused by the bacterium Salmonella typhi, which manifests with high fever, headache, general malaise, slowing of the pulse, dry cough and general disorders (constipation or more rarely diarrhoea). It is contracted mainly by ingesting contaminated water or food, but can also be spread from person to person in close contact. It is present in tropical areas with poor food and water hygiene. It is prevented chiefly by scrupulously implementing food and personal hygiene standards. Vaccination is recommended for travellers visiting areas where the disease is present.
This is the most common form of hepatitis, spread by a virus through the ingestion of contaminated water or food or by direct person-to-person contact, as occurs among family members or sexual partners of those infected. It is particularly common in Africa, Asia, Mediterranean countries, the Middle East, and Central and South America. It is characterised by fever, malaise, nausea and, after a few days, jaundice (yellowing of the skin). The disease may have a duration of 1-2 weeks or may present a more severe clinical course, with recurrent forms for several months. The severity of the clinical picture increases with the patient's age. Therefore, for those visit at-risk areas, vaccination is recommended in addition to scrupulous hygiene practices.
Hepatitis B is a viral disease, whose onset is generally insidious, characterised by lack of appetite, nausea and vomiting, and vague abdominal disorders. In most cases, jaundice appears (yellow colouring of the skin) later. Hepatitis B is mainly contracted through sexual intercourse with infected people, contact with infected blood and body fluids or contaminated instruments (transfusions, needles, syringes, tattoos, etc.). Vaccination is recommended for those travellers who are in close contact with the local population or who spend medium to long periods in high-risk areas. Vaccination is also recommended for travellers who go abroad for work or who plan to have casual sexual intercourse. It must be emphasised that vaccination protects only from hepatitis B, while the use of condoms protects (although not with absolute efficacy) from the transmission of AIDS, syphilis, gonorrhoea and other sexually-transmitted infections.
It is an acute bacterial disease, whose sudden onset is characterised by fever, intense headache, nausea (often accompanied by vomiting), and neck stiffness. The bacterium is present in the nasopharynx of infected people or carriers and is transmitted from person to person by direct contact through saliva droplets. The vaccination is recommended for travellers visiting countries where epidemics are reported or for those who live in close contact with the local population (eg health personnel, missionaries, etc.). A certificate of vaccination is required by Saudi Arabia for pilgrims going to Mecca. A single vaccine against meningococcus C and a quadrivalent vaccine against serum meningococci A, C, W, Y are currently available in Italy.
Measles, mumps, rubella
These are acute viral diseases, with airborne transmission via saliva droplets or by direct contact with the nasal or pharyngeal secretions of infected people. Vaccination is particularly recommended in children who have not yet been vaccinated and in susceptible young adults travelling abroad. The combined measles-mumps-rubella vaccine is available and can also be used in those who have already had one or more of the natural diseases or who have already been vaccinated for one of these diseases.
This is an acute febrile viral illness, with manifestations fatally affecting the central nervous system. It is transmitted by infected animals through bites, scratches or licking (saliva) and is particularly common in all countries of the tropical and subtropical zone. Vaccination should always be performed as soon as possible if bitten by an animal who may have the disease.
It is recommended before travelling for:
- those who are planning a long stay in areas where the vaccine is not readily available if needed
- those who work (even briefly) in countries where rabies is widespread and may be exposed to risk due to their activity;
- those who go to countries where rabies is endemic, in particular conditions that may favour contact with infected animals (trekking, walking, exploring caves, etc.).
Vaccinating against involves the administration of several doses of the vaccine, so it is advisable to start the process at least one month before departure. If bitten, however, it is necessary to contact a healthcare facility as soon as possible: preventive vaccination does not dispense with the need to follow a post-exposure treatment, but reduces the number of injections required and eliminates the need for the administration of human rabies immunoglobulin (HRIG).
Cholera is an acute bacterial disease, characterised by profuse diarrhoea, which is contracted through the ingestion of contaminated food or water. The risk of infection is low for tourists, while it can be high for humanitarian workers operating in disaster-stricken areas and in refugee camps. An oral vaccine is currently available.
This is a viral disease, present in vast geographical areas (India, China, Japan and throughout Southeast Asia), spread by a bite from infected mosquitoes. These species bite between dusk and dawn and most cases occur from May to September. The risk is generally low for travellers if the stay is short and limited to urban centres. It is higher, however, for those who spend long periods in rural and agricultural areas in endemic countries (especially during the monsoon season) and for those who visit rural areas, even for short stays, and remain outdoors without adequate protection in the evening and at night. In order to protect against the disease, it is very important to follow the protection measures against mosquito bites.
Tick-borne encephalitis (Tbe)
This is a viral disease, spread by a bite from infected ticks, which affects the central nervous system. It is present in most of Central Europe, especially in Austria, the Baltic States (Latvia, Estonia and Lithuania), the Czech Republic, Hungary and Russia. Several cases have also been recorded in Italy, especially in the north-eastern part (Veneto, Friuli Venezia Giulia, Trentino Alto-Adige). The prevention of the disease is centred mainly on behavioural measures to avoid tick bites and for individuals at risk of tick bites in Tbe endemic areas, vaccination is recommended.
Sources / Bibliography
- Viaggi internazionali e salute. 2011. WHO 2011, versione italiana a cura della SIMT.
- Viaggiare in Salute. Informazioni e consigli per i viaggiatori internazionali. Regione del Veneto –Direzione prevenzione. 8^ ristampa, aprile 2011.