Hepatitis A is a viral infection transmitted through contaminated food and water or by direct contact with an infectious person. Symptoms are often mild or absent in young children, but the disease becomes more serious with advancing age. Recovery can vary from weeks to months. Following hepatitis A illness, immunity is lifelong.

Those at increased risk include travellers visiting friends and relatives, long stay travellers, and those visiting areas of poor sanitation.

Prevention

All travellers should take care with personal, food and water hygiene.

Hepatitis A vaccination

As hepatitis A vaccine is well tolerated and affords long-lasting protection, it is recommended for all previously unvaccinated travellers.

Hepatitis A in brief

Tetanus is caused by a toxin released from Clostridium tetani and occurs worldwide. Tetanus bacteria are present in soil and manure and may be introduced through open wounds such as a puncture wound, burn or scratch.

Prevention

Travellers should thoroughly clean all wounds and seek appropriate medical attention.

Tetanus vaccination

• Travellers should have completed a primary vaccination course according to the UK schedule.
• If travelling to a country where medical facilities may be limited, a booster dose of a tetanus-containing vaccine is recommended if the last dose was more than ten years ago even if five doses of vaccine have been given previously.
  
  

Country specific information on medical facilities may be found in the ‘health’ section of the FCDO foreign travel advice website.

Tetanus in brief

Typhoid is a bacterial infection transmitted through contaminated food and water. Previous typhoid illness may only partially protect against re-infection.

Vaccination is recommended for most travellers, particularly travellers visiting friends and relatives, those in contact with an infected person, young children, frequent or long-stay travellers visiting areas where sanitation and food hygiene are likely to be poor, and laboratory personnel who may handle the bacteria for their work.

Prevention

All travellers should take care with personal, food and water hygiene.

Typhoid vaccination

• Oral and injectable typhoid vaccinations are available.
  
  

Typhoid in brief

Cholera is a bacterial infection transmitted by contaminated food and water. Cholera can cause severe watery diarrhoea although mild infections are common. Most travellers are at low risk.

Prevention

All travellers should take care with personal, food and water hygiene.

Cholera vaccination

This oral vaccine is recommended for those whose activities or medical history put them at increased risk. This includes:

• aid workers.
• those going to areas of cholera outbreaks who have limited access to safe water and medical care.
• those for whom vaccination is considered potentially beneficial.
  
  

 Cholera in brief

Hepatitis B is a viral infection; it is transmitted by exposure to infected blood or body fluids. This mostly occurs during sexual contact or as a result of blood-to-blood contact (for example from contaminated equipment during medical and dental procedures, tattooing or body piercing procedures, and sharing of intravenous needles). Mothers with the virus can also transmit the infection to their baby during childbirth.

Hepatitis B in Vietnam

2% or more of the population are known or thought to be persistently infected with the hepatitis B virus (intermediate/high prevalence).

Prevention

Travellers should avoid contact with blood or body fluids. This includes:

• avoiding unprotected sexual intercourse.
• avoiding tattooing, piercing, public shaving, and acupuncture (unless sterile equipment is used).
• not sharing needles or other injection equipment.
• following universal precautions if working in a medical/dental/high risk setting.
  
  

A sterile medical equipment kit may be helpful when travelling to resource poor areas.

Hepatitis B vaccination

Vaccination could be considered for all travellers, and is recommended for those whose activities or medical history put them at increased risk including:

• those who may have unprotected sex.
• those who may be exposed to contaminated needles through injecting drug use.
• those who may be exposed to blood or body fluids through their work (e.g. health workers).
• those who may be exposed to contaminated needles as a result of having medical or dental care e.g. those with pre-existing medical conditions and those travelling for medical care abroad including those intending to receive renal dialysis overseas.
• long-stay travellers.
• those who are participating in contact sports.
• families adopting children from this country.
  
  

Hepatitis B in brief

Japanese encephalitis (JE) is a viral infection transmitted to humans by the bite of an infected mosquito. These mosquitoes usually bite between dusk and dawn, mainly in rural areas; especially where there are rice fields, swamps and marshes. Mosquitoes become infected by biting JE infected animals (particularly pigs) or birds.

Travellers are at increased risk of infection when visiting rural areas. Short trips (usually less than a month) especially if only travelling to urban areas, are considered lower risk.

Japanese encephalitis in Vietnam

JE occurs in this country, with year-round transmission in the south and from May to October in the north. Cases may be reported outside these months in the north of the country.

Prevention

All travellers should avoid mosquito bites particularly between dusk and dawn.

Japanese encephalitis vaccination

• Vaccination is recommended for those whose activities put them at increased risk (see above).
• Vaccination could be considered for those on shorter trips if the risk is considered to be sufficient e.g. those spending time in areas where the mosquito breeds such as rice fields, marshlands, or pig farming areas.
  
  

Japanese encephalitis in brief

Rabies is a viral infection which is usually transmitted following contact with the saliva of an infected animal most often via a bite, scratch or lick to an open wound or mucous membrane (such as on the eye, nose or mouth). Although many different animals can transmit the virus, most cases follow a bite or scratch from an infected dog. In some parts of the world, bats are an important source of infection.

Rabies symptoms can take some time to develop, but when they do, the condition is almost always fatal.

The risk of exposure is increased by certain activities and length of stay (see below). Children are at increased risk as they are less likely to avoid contact with animals and to report a bite, scratch or lick.

Rabies in Vietnam

Rabies is considered a risk and has been reported in domestic animals in this country. Bats may also carry rabies-like viruses.

Prevention

• Travellers should avoid contact with all animals. Rabies is preventable with prompt post-exposure treatment.
• Following a possible exposure, wounds should be thoroughly cleansed and an urgent local medical assessment sought, even if the wound appears trivial.
• Post-exposure treatment and advice should be in accordance with national guidelines.
  
  

Rabies vaccination

A full course of pre-exposure vaccines simplifies and shortens the course of post-exposure treatment and removes the need for rabies immunoglobulin which is in short supply world-wide.

Pre-exposure vaccinations are recommended for travellers whose activities put them at increased risk including:

• those at risk due to their work (e.g. laboratory staff working with the virus, those working with animals or health workers who may be caring for infected patients).
• those travelling to areas where access to post-exposure treatment and medical care is limited.
• those planning higher risk activities such as running or cycling.
• long-stay travellers (more than one month).
  
  

Rabies in brief

TB is a bacterial infection transmitted most commonly by inhaling respiratory droplets from an infectious person. This is usually following prolonged or frequent close contact.

Tuberculosis in Vietnam

The average annual incidence of TB is greater than or equal to 40 cases per 100,000 population (further details).

Prevention

Travellers should avoid close contact with individuals known to have infectious pulmonary (lung) TB.

Those at risk during their work (such as healthcare workers) should take appropriate infection control precautions.

Tuberculosis (BCG) vaccination

According to current national guidance, BCG vaccine should be recommended for those at increased risk of developing severe disease and/or of exposure to TB infection e.g. when the average annual incidence of TB is greater than or equal to 40 cases per 100,000 population. See Public Health England’s Immunisation against infectious disease, the ‘Green Book’.

For travellers, BCG vaccine is also recommended for:

• unvaccinated, children under 16 years of age, who are going to live for more than 3 months in this country. A tuberculin skin test is required prior to vaccination for all children from 6 years of age and may be recommended for some younger children.
• unvaccinated, tuberculin skin test negative individuals at risk due to their work such as healthcare or laboratory workers who have direct contact with TB patients or potentially infectious clinical material and vets and abattoir workers who handle animal material, which could be infected with TB.
  
  

There are specific contraindications associated with the BCG vaccine and health professionals must be trained to administer this vaccine intradermally (just under the top layer of skin).

Following administration, no further vaccines should be administered in the same limb for 3 months.

The BCG vaccine is given once only, booster doses are not recommended.

Tuberculosis in brief

There is a risk of altitude illness when travelling to destinations of 2,500 metres (8,200 feet) or higher. Important risk factors are the altitude gained, rate of ascent and sleeping altitude. Rapid ascent without a period of acclimatisation puts a traveller at higher risk.

There are three syndromes; acute mountain sickness (AMS), high-altitude cerebral oedema (HACE) and high-altitude pulmonary oedema (HAPE). HACE and HAPE require immediate descent and medical treatment.

Altitude illness in Vietnam

There is a point of elevation in this country higher than 2,500 metres. An example place of interest: Mt Fansipan 3,143m.

Prevention

• Travellers should spend a few days at an altitude below 3,000m.
• Where possible travellers should avoid travel from altitudes less than 1,200m to altitudes greater than 3,500m in a single day.
• Ascent above 3,000m should be gradual. Travellers should avoid increasing sleeping elevation by more than 500m per day and ensure a rest day (at the same altitude) every three or four days.
• Acetazolamide can be used to assist with acclimatisation, but should not replace gradual ascent.
• Travellers who develop symptoms of AMS (headache, fatigue, loss of appetite, nausea and sleep disturbance) should avoid further ascent. In the absence of improvement or with progression of symptoms the first response should be to descend.
• Development of HACE or HAPE symptoms requires immediate descent and emergency medical treatment.
  
  

Altitude illness in brief

Insect or tick bites can cause irritation and infections of the skin at the site of a bite. They can also spread certain diseases.

Diseases in South-eastern Asia

There is a risk of insect or tick-borne diseases in some areas of South-eastern Asia. This includes diseases such as chikungunya, leishmaniasis and scrub typhus.

Prevention

• All travellers should avoid insect and tick bites day and night.
• There are no vaccinations (or medications) to prevent these diseases.
  
  

Further information about specific insect or tick-borne diseases for this country can be found, if appropriate on this page, in other sections of the country information pages and the insect and tick bite avoidance factsheet.

Dengue is a viral infection transmitted by mosquitoes which predominantly feed between dawn and dusk. It causes a flu-like illness, which can occasionally develop into a more serious life-threatening form of the disease. Severe dengue is rare in travellers.

The mosquitoes that transmit dengue are most abundant in towns, cities and surrounding areas. All travellers to dengue areas are at risk. 

Dengue in Vietnam

There is a risk of dengue in this country.

Prevention

• All travellers should avoid mosquito bites particularly between dawn and dusk.
• There is currently no medication or vaccination available for travellers to prevent dengue.
  
  

Dengue in brief

Seasonal influenza is a viral infection of the respiratory tract and spreads easily from person to person via respiratory droplets when coughing and sneezing. Symptoms appear rapidly and include fever, muscle aches, headache, malaise (feeling unwell), cough, sore throat and a runny nose. In healthy individuals, symptoms improve without treatment within two to seven days. Severe illness is more common in those aged 65 years or over, those under 2 years of age, or those who have underlying medical conditions that increase their risk for complications of influenza.

Seasonal influenza in Vietnam

Seasonal influenza occurs throughout the world. In the northern hemisphere (including the UK), most influenza occurs from as early as October through to March. In the southern hemisphere, influenza mostly occurs between April and September. In the tropics, influenza can occur throughout the year.

Prevention

All travellers should:

• Avoid close contact with symptomatic individuals
• Avoid crowded conditions where possible
• Wash their hands frequently
• Practise ‘cough hygiene’: sneezing or coughing into a tissue and promptly discarding it safely, and washing their hands
• Avoid travel if unwell with influenza-like symptoms
• A vaccine is available in certain circumstances (see below)*
  
  

*In the UK, seasonal influenza vaccine is offered routinely each year to those at higher risk of developing of severe disease following influenza infection, and certain additional groups such as healthcare workers and children as part of the UK national schedule (see information on vaccination). For those who do not fall into these groups, vaccination may be available privately.

If individuals at higher risk of severe disease following influenza infection are travelling to a country when influenza is likely to be circulating they should ensure they received a flu vaccination in the previous 12 months.

The vaccine used in the UK protects against the strains predicted to occur during the winter months of the northern hemisphere. It is not possible to obtain vaccine for the southern hemisphere in the UK, but the vaccine used during the UK influenza season should still provide important protection against strains likely to occur during the southern hemisphere influenza season, and in the tropics.

Avian influenza

Avian influenza viruses can rarely infect and cause disease in humans. Such cases are usually associated with close exposure to infected bird or animal populations. Where appropriate, information on these will be available in the outbreaks and news sections of the relevant country pages. Seasonal influenza vaccines will not provide protection against avian influenza.

Avian influenza in brief

Poor air quality is a significant public health problem in many parts of the world. Exposure to high levels of air pollution over short time periods (e.g. minutes/hours/days) and longer time periods (e.g. years) is linked to many different acute and chronic health problems. These effects are mainly on the respiratory (lungs and airways) and cardiovascular (heart function and blood circulation) systems.

Current information on world air quality is available from the world air quality index project.

Prevention

Travellers with health problems that might make them more vulnerable to the effects of air pollution who are travelling to areas of high pollution should:

• discuss their travel plans with their doctor, and carry adequate supplies of their regular medication
• take sensible precautions to minimise their exposure to high levels of air pollution
• check local air quality data and amend their activities accordingly
• take notice of any health advisories published by the local Ministry of Health and Department for Environment, and follow the guidance provided.
  
  

It is unclear if face masks are beneficial at reducing exposure and may make breathing more difficult for those with pre-existing lung conditions. Those who choose to use one should make sure that the mask fits well and know how to wear it properly.

Outdoor air quality in brief

Zika virus (ZIKV) is a viral infection transmitted by mosquitoes which predominantly feed between dawn and dusk. A small number of cases of sexual transmission of ZIKV have also been reported. Most people infected with ZIKV have no symptoms. When symptoms do occur they are usually mild and short-lived. Serious complications and deaths are not common. However ZIKV is a cause of Congenital Zika Syndrome (microcephaly and other congenital anomalies) and neurological complications such as Guillain-Barré syndrome.

Zika virus in Vietnam

There is a risk of ZIKV in this country. Pregnant women should consider avoiding travel to this country until after the pregnancy. In the event that travel is unavoidable, the pregnant traveller must be informed of the risks which ZIKV presents.

Details of specific affected areas within this country are not available but the mosquitoes that transmit ZIKV are unlikely to be found above 2,000m altitude. Vietnam has some locations over 2,000m.

Prevention

• All travellers should avoid mosquito bites particularly between dawn and dusk.
• There is no vaccination or medication to prevent ZIKV infection.
• Women should avoid becoming pregnant while travelling in this country, and for 2 months (8 weeks) after their last possible ZIKV exposure* (see below if male partner has travelled).
• If a woman develops symptoms compatible with ZIKV infection, it is recommended she avoids becoming pregnant for a further 2 months following recovery.
• Pregnant women who visited this country while pregnant, or who become pregnant within 2 months after their last possible ZIKV exposure*, should contact their GP, obstetrician or midwife for further advice, even if they have not been unwell. 
  
  

Please note screening of returning travellers without ZIKV symptoms is not available on the NHS. Couples planning pregnancy in the very near future should consider whether they should avoid travel to a country or area with risk of ZIKV, rather than delay conception for the recommended period (see below) after travel. This particularly includes couples in assisted fertility programmes.

Preventing sexual transmission

Couples should follow guidance on prevention of sexual transmission of ZIKV and avoid conception as follows:

• If both partners travelled, for 3 months after last possible ZIKV exposure*
• Male traveller only, for 3 months after last possible ZIKV exposure*
• Female traveller only, for 2 months after last possible ZIKV exposure*
  
  

See further information for pregnant women, their partners and couples planning pregnancy.

*Last possible Zika virus exposure is defined as the later of either the date of leaving a country or area with risk for ZIKV transmission, or the date on which unprotected sexual contact with a potentially infectious partner took place.

See detailed guidance on factors to consider when assessing the risk of ZIKV.

Zika virus in brief