Vaccinations

• Dengue fever is the world's most common insect-borne infectious disease.
• Great attention should be paid to mosquito protection during the day!
• The disease can cause high fever, muscle and joint pain, and skin rashes. In rare cases, bleeding may occur. There is no specific treatment.
• For personal safety, we strongly recommend that you inform yourself in detail about dengue.

Dengue fever is the most common insect-borne infectious disease worldwide. There are 4 known serotypes of dengue virus, so it is possible to be infected with dengue more than once. Approximately 1 in 4 infected individuals develop symptoms of dengue, resulting in high fever, muscle and joint pain, and skin rash. In rare cases, most often after a second infection, life-threatening bleeding and shock (severe drop of blood pressure) may occur.

In 3 out of 4 cases, an infection with the virus remains asymptomatic. After a short incubation period (5-8 days), 1 out of 4 infected people present an abrupt onset of fever, headache, joint, limb and muscle pain, as well as nausea and vomiting. Eye movement pain is also typical. A rash usually appears on the 3rd or 4th day of illness. After 4 to 7 days, the fever finally subsides but fatigue may persist for several days or weeks.

In rare cases, severe dengue can occur. Particularly susceptible are local children and seniors as well as people who have experienced a prior dengue infection. Tourists extremely rarely present with severe dengue. In the first days, the disease resembles the course of classic dengue fever, but on the 4th/5th day, and usually after the fever has subsided, the condition worsens. Blood pressure drops, and patients complain of shortness of breath, abdominal discomfort, nosebleeds, and mild skin or mucosal hemorrhages. In the most severe cases, life-threatening shock may occur.

There is no specific treatment for dengue virus infection. Treatment is limited to mitigation and monitoring of symptoms: fever reduction, relief of eye, back, muscle and joint pain, and monitoring of blood clotting and blood volume. Patients with severe symptoms must be hospitalised.

For treatment of fever or pain, paracetamol or acetaminophen are recommended (e.g. Acetalgin® Dafalgan®). Drugs containing the active ingredient acetylsalicylic acid (e.g. Aspirin®, Alcacyl®, Aspégic®) must be avoided.

Effective mosquito protection during the day and especially during twilight hours (i.e. sunset) is the best preventive measure:

1. Clothing: Wear well-covering, long-sleeved clothing and long pants and spray clothing with insecticide beforehand (see factsheet “prevention of arthropod bites”)
   
2. Mosquito repellent: Apply a mosquito repellent to uncovered skin several times a day (see factsheet “prevention of arthropod bites”)
   
3. Environmental hygiene: Do not leave containers with standing water (coasters for flower pots, etc.) in your environment to avoid mosquito breeding sites.

Note on dengue vaccines:

two vaccines against dengue are on the market: Qdenga®and Dengvaxia®. The Qdenga® vaccine was approved by the European Union in December 2022. 

However, due to the data available, many European countries, as well as the Swiss Expert Committee for Travel Medicine (ECTM), currently recommend vaccination with Qdenga® only for certain travelers and in special situations. Consultation with a specialist in tropical and travel medicine is therefore recommended.

Of note:

• Qdenga® is not yet licensed in Switzerland and the recommendations for travelers will be limited once Qdenga® is licensed  in Switzerland. 
  
• The vaccine Dengvaxia® is not a vaccine for travelers.
  

Consistent mosquito protection during the day (see above) is still considered the most important preventive measure against dengue!

• Hepatitis A is a liver infection caused by a virus.
• The virus is easily transmitted by contaminated food or water but can also be transmitted through sexual contact.
• A safe and very effective vaccine is available that affords long-lasting protection.
• Hepatitis A vaccination is recommended for all travelers going to tropical or subtropical countries, and for risk groups.

Hepatitis A occurs all over the world, but the risk of infection is higher in countries with poor hygiene standards. There is an increased risk in most tropical and subtropical countries, as well as in some countries in Eastern Europe and around the Mediterranean.

In recent years, there have also been increasing cases in North America and Europe, including Switzerland, especially among men who have sex with men (MSM). Outbreaks in northern European countries can also occur when unvaccinated children become infected during family visits to tropical and subtropical countries. Upon return, they may transmit the virus within their care facilities.

There is a safe and very effective vaccine that consists of two injections at least 6 months apart. It provides lifelong protection after the second dose. Hepatitis A vaccination can also be given in combination with hepatitis B vaccination (3 doses required).

Vaccination against hepatitis A is recommended for all travellers to risk areas, as well as for persons at increased personal risk: persons with chronic liver disease, men who have sex with men, people who use or inject drug, persons with increased occupational contact with persons from high-risk areas or populations, and others.

• Federal Office of Public Health (FOPH). Hepatitis A. https://www.bag.admin.ch/bag/en/home/krankheiten/krankheiten-im-ueberblick/hepatitis-a.html 
• Swiss Hepatitis: https://en.hepatitis-schweiz.ch/all-about-hepatitis/hepatitis-a 

• Viral disease transmitted by night-biting mosquitoes in rural/suburban areas.
• Very rare in travelers.
• Mostly mild or without symptoms; severe illness is rare but has a high mortality.
• Vaccine available for those at increased risk, such as long-term travelers to endemic areas.

• WHO Factsheet Japanese Encephalitis: https://www.who.int/news-room/fact-sheets/detail/japanese-encephalitis
• Solomon et al., Japanese Encephalitis, BMJ 2000: https://jnnp.bmj.com/content/jnnp/68/4/405.full.pdf
• CDC Japanese Encephalitis: https://www.cdc.gov/japaneseencephalitis/index.html 

• Meningococcal disease is a very severe, life threatening bacterial infection that can lead to death within a few hours if untreated.
• Transmission occurs from person to person by droplets. The risk is higher for travelers to regions with seasonal epidemics (meningitis belt in sub-Saharan Africa).
• The disease can be prevented by one dose of four-valent meningococcal vaccine and protection lasts for at least 5 years.

Meningococcal vaccination is recommended in Switzerland as a complementary vaccination for children between 2 – 4 years and for adolescents between 11 – 15 years. Furthermore, it is recommended as a risk group vaccination for persons with certain medical conditions, for persons with close contact to a patient with meningococcal disease and for travelers to endemic areas.

For more detailed information on the disease and Swiss national recommendations (in German, French, Italian) see: https://www.bag.admin.ch/bag/de/home/krankheiten/krankheiten-im-ueberblick/meningokokken-erkrankungen.html

• Polio is a vaccine-preventable viral disease of the nervous system that is acquired mainly through the consumption of food or water contaminated by feces.
• The infection with the polio virus can affect children and adults and may lead to permanent limb or respiratory muscle paralysis and death.
• An effective, well- tolerated vaccine is available! Check if booster doses are recommended for the travel destination (on top of completed basic vaccination schedule).

Regular hand washing after using the bathroom and before eating or preparing food. Avoidance of undercooked or raw food that is potentially contaminated with fecal material.

The most important prevention is vaccination. A very effective and well-tolerated vaccine against polio is available (inactivated (killed) polio vaccine (IPV)), which is part of the basic vaccination schedule during childhood. Combination vaccines (e.g. with diphtheria and tetanus) are also available. After basic vaccination, a booster dose is recommended every 10 years for travel to certain countries (see country page recommendations). WHO recommends a yearly vaccination for residents or long-stay visitors (minimum 4 weeks) in a country with ongoing polio infections or circulating vaccine-derived polio viruses. This recommendation not only targets individual protection, but aims to prevent the international spread of the virus.

WHO: https://www.who.int/news-room/fact-sheets/detail/poliomyelitis

FOPH Switzerland: Swiss vaccination plan: https://www.bag.admin.ch/bag/de/home/gesund-leben/gesundheitsfoerderung-und-praevention/impfungen-prophylaxe/schweizerischer-impfplan.html

• Rabies is mainly transmitted by dogs (and bats), but any mammal can be infectious.
  
• It is invariably fatal at the time when symptoms occur.
  
• Rabies is best prevented by a pre-travel vaccination and appropriate behavior towards mammals.
• Pre-travel vaccination is also recommended because vaccines and immunoglobulins are often not available in many travel countries. Vaccination before travel is highly recommended in particular for
  
  • long-term stay in endemic countries,
    
  • short journeys with high individual risk such as travellers on ‘two wheels’ or treks in remote areas, toddlers and children up to 8 years of age,
    
  • professionals working with animals, or cave explorers (bats!).
• Attention: a bite or scratch wound as well as contact with mammal saliva is an emergency! Find out about the necessary actions below!

No treatment against rabies disease exists.

Post-exposure measures:

• Immediate cleaning of the wound with plenty of water and soap for 10-15 minutes, followed by disinfection (e.g. Betadine, Merfen) and emergency post-exposure vaccination at the nearest health institution within 24 hours.
  
• Tetanus booster vaccination is also required.
  
• For those having received full pre-exposure rabies vaccination before travel: two additional vaccine shots (any available brand) at an interval of 3 days suffice.
  
• If full pre-exposure vaccination has not been given, in addition to vaccination, passive immunization is required with immunoglobulins.
  
• It should be noted that immunoglobins (and sometimes vaccines) are often unavailable in low-resource settings, causing stress and uncertainty.

Stroking cute pets is not a good idea; refrain from touching wild or unfamiliar or dead animals.
All travellers to places where rabies may occur and who are likely to take repeated trips to areas where rabies occurs should have a pre-exposure vaccination. In addition, pre-exposure vaccination is highly recommended for travellers at particular risk:

• long-term stay in endemic countries,
  
• short journeys with high individual risk such as travellers on ‘two wheels’ or treks in remote areas, toddlers and children up to 8 years of age,
  
• professionals working with animals, or cave explorers (bats!).
  

The shortened vaccination schedule can be proposed to most travellers: 2 shots, the first one at one month before departure if possible (minimum: 8 days before departure). A single third rabies booster vaccination is recommended before the next trip, at least after one year.

• Obtain information about prevention of rabies in time before travelling.
  
• In case of trips planned for longer than a few weeks, schedule a visit at the travel clinic 4 weeks before departure at the latest.
  
• After possible exposure (bite, scratch injury) wound treatment and additional vaccinations are necessary even for those with a completed series of basic vaccinations.
  
• This information leaflet should be printed and kept handy during the trip!

• FOPH Switzerland (German): https://www.bag.admin.ch/dam/bag/de/dokumente/mt/infektionskrankheiten/tollwut/bag-bulletin-15-2021-tollwut-prep-und-pep.pdf.download.pdf/210412_BAG_Bulletin_15_2021_Tollwut%20PrEP%20und%20PEP_d.pdf 
  
• FOPH Switzerland (French): https://www.bundespublikationen.admin.ch/cshop_mimes_bbl/14/1402EC7524F81EDBA5D6C3EBC18BA9FB.pdf 

• Typhoid fever, also called enteric fever, is caused by the bacteria Salmonella Typhi and Salmonella Paratyphi.
• Infected persons shed the bacteria in their feces. In countries with low sanitation standards, the bacteria can then enter the drinking water system and lead to infections in other people.
• Frequent sources of infection are contaminated food and beverages.
• The main preventive measure therefore is “cook it, peel it, boil it or forget it” – meaning: avoid drinking uncooked water or water from unsealed bottles; avoid cooled/frozen products (e.g. ice cubes in drinks, ice cream) unless from a known safe source; avoid uncooked vegetables, peel and clean fruit and vegetables yourself and only with known safe drinking water.
• A vaccine is available and recommended: a) for travelers to the Indian subcontinent or to West Africa, b) for travelers visiting friends and relatives or for long-term travelers also to other sub-/tropical areas.

“Cook it, boil it, peel it or forget it” – this simple slogan would be sufficient to prevent typhoid fever nearly entirely. However, only few travelers fully adhere to this advice. Nevertheless, the value of food and water hygiene cannot be stressed enough: avoid buying water bottles without proper sealing, avoid drinking tap water from unknown sources, avoid eating cooled / frozen foods (i.e. ice cubes in water or ice cream) and avoid eating raw fruits and vegetables that you yourself have not peeled and washed with clean drinking water.

Two types of vaccines are available:

• Oral (live) vaccine consisting of three capsules to be taken on alternate days on empty stomach. These capsules require refrigeration before use. Protection from this vaccine is approximately 70% and starts 10 days after the third dose. After 1 to 3 years, the vaccine needs to be taken again before a new travel into at-risk areas. This vaccine cannot be given to patients with a severe chronic gastrointestinal disease (such as Crohn’s disease or ulcerative colitis) or with severe immunosuppression.
• The single-dose vaccine is an inactivated vaccine and is injected intramuscularly. Protection also reaches around 70% and starts 14 days after the injection. This vaccine can be given to patients who should not take the oral vaccine. However, it is not registered in Switzerland, but most doctors with specialization in tropical and travel medicine and all travel health centres have the vaccine on stock. Duration of protection is around 3 years.

• Yellow fever occurs in sub-Saharan Africa and South America and is transmitted by mosquitoes.
• Disease may be severe in unvaccinated travelers and death may occur in over 50%.
• A highly effective vaccine is available.
• Due to potentially severe side effects the vaccine is used with caution in immunocompromised or elderly individuals, as well as in pregnant women.

As against all mosquito-borne diseases, prevention from mosquito bites is during day and night (see “Insect and tick bite protection” factsheet). The available vaccine is highly efficacious and provides a long-term protection. It is recommended for people aged 9 months or older who are travelling to yellow fever endemic areas. In addition, providing proof of vaccination may be mandatory for entry into certain countries.

The vaccine is a live-attenuated form of the virus. In immunocompetent persons, protection starts about 10 days after the first vaccination. Reactions to yellow fever vaccine are generally mild and include headache, muscle aches, and low-grade fevers.  Side effects can be treated with paracetamol but aspirin and other nonsteroidal anti-inflammatory drugs, for example ibuprofen or naproxen, should be avoided.  On extremely rare occasions, people may develop severe, sometimes life-threatening reactions to the yellow fever vaccine – which is why this vaccine is used with caution in immunocompromised individuals, pregnant women and the elderly for safety reasons. Talk to your travel health advisor if you belong to this group.