Topic
Travel-Associated Viral Infections
The viral infections that matter when people cross borders: the pre-travel consultation that prevents them, the vaccines demanded, recommended and reviewed for travellers, and the approach to the returning traveller who falls ill.
International travel moves people, and the viruses they carry, faster than any natural process. A susceptible traveller can incubate a virus acquired in one continent and develop the illness in another, seeding onward transmission in a population with no immunity. Travel medicine exists to manage that risk from both directions: protecting the individual traveller from what they may meet abroad, and protecting communities from what a traveller may bring home.
The viral work of travel medicine rests on two encounters. The first is the pre-travel consultation, weeks before departure, where risk is assessed against the itinerary and the right vaccines and advice are given. The second is the returning traveller who presents with fever or another syndrome, where the task is a structured differential built on where they went, what they did, and how long ago. Vaccines organise the first encounter; incubation periods and geography organise the second.
→ See Travel-Associated Viral Infections: an Overview for the pre-travel risk assessment, the three categories of travel vaccine, the required vaccines and the International Health Regulations, the vaccine-preventable and non-vaccine-preventable viral infections of the traveller, the approach to the returning traveller with fever, special traveller groups, and the South African context.
The cross-cutting biology of the mosquito- and tick-borne viruses that dominate travel-associated disease is treated in the Arboviruses article, and the individual agents each have a full profile in the virus atlas.
Travel vaccines by category
Travel vaccines are grouped by the reason they are given, a distinction that governs both the clinical decision and the legal requirement.
| Category | What it means | Examples |
|---|---|---|
| Routine | National-programme vaccines, reviewed and caught up | Measles-mumps-rubella, hepatitis B, influenza, polio, HPV, varicella, rotavirus |
| Recommended | Given for diseases endemic at the destination | Hepatitis A, Japanese encephalitis, tick-borne encephalitis, rabies, typhoid, cholera |
| Required | Demanded as a condition of entry under the International Health Regulations | Yellow fever, polio, meningococcal |
Viral travel infections at a glance
Whether a vaccine exists and, either way, the measure that actually protects the traveller.
| Infection | Traveller vaccine | Main preventive measure |
|---|---|---|
| Yellow fever | Yes, live, single dose | Vaccination and mosquito-bite avoidance |
| Japanese encephalitis | Yes, inactivated | Vaccination for rural Asia and bite avoidance |
| Tick-borne encephalitis | Yes, inactivated | Vaccination and tick-bite avoidance |
| Rabies | Yes, pre-exposure | Vaccination, animal avoidance, prompt post-exposure care |
| Hepatitis A | Yes, inactivated | Vaccination and safe food and water |
| Measles | Yes, in measles-mumps-rubella | Two documented doses |
| Influenza | Yes, seasonal | Vaccination for the relevant season |
| Dengue | Limited, not routine | Day-time mosquito-bite avoidance |
| Zika | None | Bite avoidance and reproductive precautions |
| Chikungunya | Recent, outbreak use | Day-time mosquito-bite avoidance |
| Norovirus | None | Handwashing with soap and water, safe food |
Key terms
| Term | Meaning |
|---|---|
| Routine vaccine | Part of a national programme; reviewed and caught up at the pre-travel visit. |
| Recommended vaccine | Given because the disease is endemic at the destination. |
| Required vaccine | Demanded as a condition of entry under the International Health Regulations. |
| International Health Regulations (IHR) | The binding international framework that lets a country require certain vaccinations for entry. |
| International Certificate of Vaccination or Prophylaxis (ICVP) | The “yellow card” recording a required vaccination; the yellow fever certificate is valid for the life of the vaccinee. |
| Pre-travel consultation | The visit, ideally four to eight weeks ahead, that assesses risk and gives vaccines and advice. |
| Visiting friends and relatives (VFR) | Travellers returning to a country of origin, a high-risk and under-consulted group. |
| Antibody-dependent enhancement | The mechanism by which a second dengue serotype can cause more severe disease. |
| Post-exposure prophylaxis (PEP) | Vaccine, immunoglobulin or both given after a defined exposure, as for rabies or hepatitis B. |
References and recommended reading
- World Health Organization. International Travel and Health, Chapter 6: Vaccine-preventable diseases and vaccines (2019 update). Geneva: WHO; 2020. The standing international framework for travel vaccination.
- Centers for Disease Control and Prevention. CDC Yellow Book: Health Information for International Travel, 2026 edition. Oxford University Press; 2025. The current, frequently updated reference for travel-associated infections and vaccines.