Travel vaccinations for tourists: Keeping your trips safe!

Travel vaccines for tourists 

Yellow fever vaccine

Yellow fever is an acute viral hemorrhagic disease transmitted by infected mosquitoes. Yellow fever can be prevented by an extremely effective vaccine which is safe and affordable. A single dose of yellow fever vaccine is sufficient to confer sustained immunity and life-long protection against yellow fever disease. A booster dose of the vaccine might be needed every 10 years, or as advised. The vaccine provides effective immunity within 10 days for 80-100% of people vaccinated and within 30 days for more than 99% of people vaccinated.  The International Health Regulations (IHR) highly recommends travelers to receive yellow fever vaccine  at least 10 days before travelling to endemic areas of yellow fever including Central Africa and  South America. In accordance with the IHR, countries have the right to require travellers to provide a certificate of yellow fever vaccination. If there are medical grounds for not getting vaccinated, this must be certified by the appropriate authorities. 

Influenza vaccine

Influenza is an acute respiratory illness that affects the upper or lower respiratory tract. It is caused by influenza virus, typically type A or B. Influenza circulates continuously, causing seasonal epidemics in temperate regions and year-round epidemics in some tropical regions. Influenza viruses are continuously changing, necessitating annual change in vaccine strains to better match with currently circulating influenza strains globally. In Thailand, it is highly recommended to receive influenza vaccine before rainy season begins. For travelers, this vaccine should be administered at least 2 weeks prior to the trip. 

Typhoid fever vaccine

Although the risk of illness with typhoid fever increases with the duration of stay, travelers have acquired typhoid fever vaccine even during short visit to countries where the disease is highly endemic e.g. India, Africa, South Asia, Southeast Asia, South America, the Middle East, Europe and Central America. Vaccination against typhoid fever is extremely vital if close contact to poor hygiene is needed e.g. contaminated food and water. 

This single-dose intramuscular or subcutaneous injectable vaccine provides approximately 70% protection against blood culture-confirmed typhoid fever. It is advised to receive this vaccine 1 month before traveling to endemic areas.  In case of long stay, the need for repeat doses is every 3 years. 

Hepatitis A vaccine

Hepatitis A is a liver disease caused by the hepatitis A virus. The virus is primarily spread when an uninfected (and unvaccinated) person ingests food or water that is contaminated with the feces of an infected person. The disease is closely associated with unsafe water or food, inadequate sanitation, poor personal hygiene and oral-anal sex. Hepatitis A vaccine is essentially recommended particularly in high risk groups including patients diagnosed with chronic liver disease, chefs,  men who have sexual contact with men, people who inject drugs or share needles, syringes or other drug equipment and travelers to endemic countries of hepatitis A infection.  Inactivated hepatitis A vaccines are safe and highly effective. Traditionally, a two-dose schedule is recommended.  These 2 doses should be given at least 6-12 months apart.

Hepatitis B vaccine

Hepatitis B is a viral infection that attacks the liver and can cause both acute and chronic disease. It is the most serious type of viral hepatitis, leading to liver cirrhosis and liver cancer.  The virus is highly contagious and  transmitted through contact with the blood or other body fluids of an infected person. 

People who are at greater risk of hepatitis B infection include   drug users who inject drugs or share needles, syringes or other drug equipment,  men who have sexual contact with men, patients with kidney failure who undergo hemodialysis, patients who frequently receive blood transfusion and people with family history of hepatitis B infection.  Hepatitis B is preventable with currently available safe and effective vaccines.  The hepatitis B vaccine is an injection that is generally given in the arm and as a three-dose series on a 0, 1 and 6-month schedule.

Rabies vaccine

Rabies is an infectious viral disease that is almost always fatal following the onset of clinical symptoms. Domestic dogs are mainly responsible for rabies virus transmission to humans. It is spread to people through bites or scratches, usually via saliva.  Vaccination against rabies is used in two distinct situations; pre-exposure vaccination and post-exposure prophylaxis to prevent the development of clinical rabies after exposure has occurred, usually following the bite of an animal suspected of having rabies. 

The vaccines used for pre-exposure and post-exposure vaccination are the same, but the immunization schedule differs. Rabies immunoglobulin is used only for post-exposure prophylaxis. Pre-exposure vaccination is recommended for travelers who have plans to visit and stay at least 1 month in the endemic areas of animal that might be infected with rabies virus.  Pre-exposure vaccination should be also offered to people at high risk of exposure to rabies such as laboratory staff working with rabies virus, veterinarians, animal handlers and wildlife officers.  Pre-exposure rabies vaccination consists of three full intramuscular doses of cell-culture- or embryonated-egg-based vaccine given on days 0, 7 and 21 or 28. The fourth dose seems unnecessary for travelers unless previous vaccination against rabies in the last 10 years was administered. 

Meningococcal vaccine

Meningococcal meningitis is a rare but serious bacterial infection. It causes the membranes that cover the brain and spinal cord to become inflamed.  Meningococcal meningitis is observed worldwide but the highest burden of the disease is in the meningitis belt of Africa and  Saudi Arabia. Meningococcal infections are transmitted through contact with respiratory droplets or secretions.  Currently there are several polysaccharide and conjugate vaccines available for protection from the most common serogroups of meningococcal disease.   Saudi Arabia demands proof of recent meningococcal vaccination (tetravalent vaccine) as a visa requirement for pilgrims during The Hajj, an annual Islamic pilgrimage to Mecca. The single-dose vaccination is recommended 2-3 weeks before traveling to high risk zones. 

Cholera vaccine

Cholera is an acute intestinal infection caused by ingestion of food or water contaminated with the bacterium Vibrio cholerae. It is a disease of poverty, closely linked to poor sanitation and lack of clean drinking water. It is characterized in the majority of cases by acute, profuse watery diarrhea lasting from one to a few days. In its extreme form, cholera can be rapidly fatal. The endemic areas include Africa, South Asia or Southeast  Asia, the Middle East, Central America and  Caribbean countries.  Cholera vaccines are vaccines that are effective at preventing cholera. The vaccines are in oral dosage form. In adults, cholera vaccine must be administered 2 doses. There must be a minimum of 7 days and no more than 6 weeks, delay between each dose. Children aged 2-5 require a third dose with the same interval. Vaccines must be completely given before traveling at least 1 week. 

Measles, Mumps, Rubella vaccine

Measles is a highly infectious respiratory disease that can result in severe and permanent complications including pneumonia, seizures and brain damage. It is highly contagious. It spreads easily by contact with an infected person through coughing and sneezing.  Mumps is caused by the mumps virus, which lives and reproduces in the upper respiratory tract. It is spread through mucus or saliva when an infected person coughs or sneezes. Mumps can lead to serious complications such as deafness, meningitis (infection of the brain and spinal cord covering) and painful swelling of the testicles or ovaries.  Rubella, also known as German measles, is a viral disease spread by contact with an infected person through coughing and sneezing. While rubella is typically mild in children, adults tend to have more complications.  Combined live vaccine for measles, mumps and rubella (MMR) is used widely for the immunization of children in certain regions of the world because of its advantages over the individual vaccines. Combined vaccine provokes an adequate immune response in children simultaneously for the three infections.  It is essentially recommended to all children to get two doses of MMR vaccine, starting with the first dose at 12 through 13 months of age and the second dose at 4 through 6 years of age (school age). In adults, it is suggested to receive 2 doses of MMR vaccine with 1-month interval while the second dose must be received at least 2 weeks prior to traveling.