When counselling travellers about the need, benefits and risks of travel vaccines, the following factors must be considered:
o Environmental factors, e.g., destination, duration of exposure (including expected cumulative life-time exposure), epidemiological situation, travel style (low budget associated with higher risk), travel purpose (visiting friends or relatives [VFR] - often results in higher risk)
o Host factors include e.g. age, origin (potential exposure at home vs. at destination, is there an incremental risk?), pre-existing illness, particularly immune suppression (e.g. HIV, medication), pregnancy, nursing
A structured discussion about required, routine and recommended vaccinations is beneficial
o Required by destination country: yellow fever (special rules based on the International Health Regulations), meningococcal disease (Hajj), COVID-19
o Routine: usual childhood / adolescence / adult / senior citizen vaccinations. Programs differ between countries. Some proof of vaccination may be required for schools mainly in North America.
o Recommended: depending on exposure to risk (incidence rate, also incremental risk compared to home country), impact of infection, cost of vaccines, etc.
Essentials when protecting travellers against vaccine preventable diseases:
o Set correct priorities; base decisions on epidemiological evidence; consider contraindications
o Always state that
No vaccine is 100% effective;
All vaccines may have adverse reactions, rarely serious ones.