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. Vaccination is recommended only for people with evidence of previous dengue infection.
• 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-covered, long-sleeved clothing and long pants and treat 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.

For further information, please refer to the factsheet on "Mosquito and tick bite protection".

Note on the dengue vaccine Qdenga®:

• Based on the data available, many European countries, as well as the Swiss Expert Committee for Travel Medicine (ECTM), currently recommend vaccination with Qdenga® only for travelers who have evidence of a previous dengue infection and who will be exposed in a region with significant dengue transmission. This is a precautionary decision, since the current data also include the possibility that people who are vaccinated with Qdenga® before a first dengue infection may experience a more severe course of the disease. A consultation with a specialist in tropical and travel medicine is recommended.

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

Of note

• Do not take any products containing the active ingredient acetylsalicylic acid (e.g. Aspirin®, Alcacyl®, Aspégic®) if you have symptoms, as they increase the risk of bleeding in the event of a dengue infection!
• However, do not stop taking medications containing acetylsalicylic acid if it is already part of your regular treatment for an underlying condition.

• Do not take any products containing the active ingredient acetylsalicylic acid (e.g. Aspirin®, Alcacyl®, Aspégic®) if you have symptoms, as they increase the risk of bleeding in the event of a dengue infection!
• However, do not stop taking medications containing acetylsalicylic acid if it is already part of your regular treatment for an underlying condition.

• 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

• Mpox is a viral disease that typically causes a rash, swollen lymph nodes and fever.
• An emerging variant is spreading rapidly in eastern D.R. Congo and neighboring countries prompting a new WHO declaration of a public health emergency of international concern (PHEIC), as of August 14th 2024.
• Close physical contact (sexual or non-sexual) is the main mode of transmission.
• The disease generally follows a mild course. Children, pregnant women, and people with weak immune systems are the most at risk of complications.
• Vaccination against mpox is available, but limited to groups at high risk of exposure. 

Mpox has been commonly found in West and Central Africa for many years where the suspected reservoir - small mammals - is endemic. There are two types of Monkeypox virus called ‘clades’ that cause the disease mpox - clade I in Central Africa and clade II in West Africa. Since the end of smallpox vaccination campaigns in the early 1980’s, cases of mpox have increased, slowly at first and significantly in the last 5-10 years, especially in the Democratic Republic of Congo (DRC).

In 2022, a new emerging subclade of clade II was responsible for a global epidemic that spread mainly through sexual contact among men who have sex with men. It resulted in the first public health emergency of international concern (PHEIC) declared by the WHO until 2023. Although the clade II epidemic is now under control, this virus variant continues to circulate worldwide.

In 2024, the continued spread of mpox clade I in endemic regions of Central Africa, particularly in the DRC, and the emergence of a new subclade Ib in Eastern DRC and neighboring countries have raised global concern and prompted the WHO to declare a PHEIC for the second time in two years. The current geographical spread of the mpox clade Ib variant occurs via commercial routes through sexual contact (e.g. sex workers), followed by local transmission in households and other settings (which is becoming increasingly important).

Animal to human transmission
Mpox can spread from animal to human when they come into direct contact with an infected animal (rodents or primates).

Human to human transmission
Mpox can be spread from person to person through close physical contact (sexual and non-sexual contact) with someone who has symptoms of mpox. Skin and mucous membrane lesions, body fluids, and scabs are particularly infectious. A person can also become infected by touching or handling clothing, bedding, towels, or objects such as eating utensils/dishes that have been contaminated by contact with a person with symptoms. Household members, family caretakers, and sexual partners of a confirmed case of mpox are at higher risk for infection as are health care workers who treat a case without adequate personal protection.

The incubation period (time between infection and onset of symptoms) ranges from a few days up to 3 weeks. Mpox causes a rash / skin eruption that can be painful associated with swollen lymph nodes and fever. Fever may start already before the rash phase. Other symptoms include muscle aches, back pain, and fatigue. The rash may be localized or generalized, with few or hundreds of skin lesions. It mainly affects the face, the trunk and the palms of hand and soles of the feet. It can also be present in genital areas and on mucous membranes such as in the mouth and throat. Symptoms usually last 2 to 4 weeks and the person remains contagious until all lesions have healed (once the cabs have fallen off).

Complications include secondary bacterial infections, infections of the lung and brain and involvement of other organs, still birth and others. Children, pregnant women, and people with weak immune systems are at higher risk to develop a severe form of mpox.

The majority of person with mpox recovers spontaneously and do not need specific antiviral treatment. Care management consists of relieving pain and other symptoms and preventing complications (e.g., superinfection). Several antiviral treatments are studied in various countries and may be used in trials or in clinical situations according to the recommendations of national medical societies.

In case of symptoms: 

• Seek medical attention immediately
• If you are diagnosed with mpox
  • Please stay at home (isolate yourself) until your mpox rash has healed and a new layer of skin has formed. Staying away from other people and not sharing things you have touched with others will help prevent the spread of mpox. People with mpox should regularly clean and disinfect the spaces they use to limit household contamination.
  • Wash your hands often with soap and water or an alcohol-based hand sanitiser containing at least 60% alcohol.
  • You should not have sex while symptomatic and while you have lesions or symptoms. Use condoms for 12 weeks after infection. This is a precaution to reduce the risk of spreading the virus to a partner.
  • For more information on what do if you are sick, see CDC LINK.

General precautions:

• Worldwide:
  • avoid close, skin-to-skin contact with people who have or may have mpox or people who have a rash (e.g., pimples, blisters, scabs).
  • Wash your hands often with soap and water or an alcohol-based hand sanitiser containing at least 60% alcohol.
  • Avoid touching potentially contaminated personal items such as cups, bedding/clothing, towels or sharing eating utensils/cups, food or drink with a person who has, or may have mpox.
  • Avoid sex with sick persons; use of condoms for up to 12 weeks if you sexual partner have had mpox.
  • Follow advice of local authorities.

• When travelling to endemic / epidemic areas in Africa, in addition to above mentioned general precautions: 
  • Avoid contact with and animals in areas where mpox regularly occurs.
  • Avoid eating or preparing meat from wild animals (bushmeat) or using products (creams, lotions, powders) derived from wild animals.

Vaccination:

There are several vaccines against mpox (e.g. Jynneos®, manufacture Bavarian Nordic). The Bavarian Nordic vaccine was originally developed to fight against smallpox, but offers a cross-protection against mpox. In Switzerland, the Jynneos® vaccine has been licensed by Swissmedic since 2024. Groups at risk (e.g., men who have sex with men or transgender people with multiple sex partners) are eligible for vaccination since 2022 and this recommendation remains unchanged (see FOPH recommendations). In light of the epidemiological situation in Africa in 2024, the Swiss Expert Committee for Travel Medicine recommends vaccination against mpox for professionals who are / will be in contact with suspect mpox patients or animals in endemic/epidemic regions or who work in a laboratory with the virus (for updates, see news).

The risk to the general population and travelers (tourists) is considered extremely low if the above-mentioned general precautions are followed and vaccination is not recommended.

• Seek medical attention immediately.
• Mpox is not a sexual transmitted disease in the strict sense, physical contact with a person with symptoms of mpox (rash at any stage) is sufficient to transmit the disease. Condoms do not protect you from getting mpox!

• Swiss Federal Office of Public Health (FOPH)                                                            
• World Health Organisation: WHO FAQ
• European Center of Disease Control and Prevention (ECDC)
• US Center of Disease Control and Prevention (CDC)

• 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.