Recommendation
E) A+B+C — vaccinate travelers going to a tropical country with an influenza outbreak, those in group travel/cruise settings, and those traveling to the Southern Hemisphere during its influenza season; do not vaccinate specifically because of MERS risk. 1, 2
Evidence-based rationale (prioritizing morbidity, mortality, QOL)
- ACIP (most recent 2024–25): Recommends influenza vaccination for travelers who wish to reduce risk, especially those at higher risk of complications, when traveling to the tropics (year-round circulation), to the Southern Hemisphere during April–September, or with organized tourist groups/cruise ships to any location. 1
- Prior ACIP (2019–20) concordant: Same three indications for travelers. 2
- No ACIP/CDC recommendation to receive influenza vaccine due to MERS; MERS prevention is unrelated to influenza immunization. 1
Practical algorithm
- If travel plan includes:
- Tropical country with ongoing influenza circulation/outbreak → vaccinate ≥2 weeks pre-departure. 1
- Cruise or large organized group with mixed origins → vaccinate. 1
- Southern Hemisphere during April–September (e.g., Greece summer to Australia winter) → vaccinate; Southern Hemisphere formulation may be reasonable but often unavailable in the U.S.; use current locally available vaccine if SH product not accessible. 1
- If travel is to Arabian Peninsula solely due to MERS concern → do not use influenza vaccine for MERS prevention; address MERS-specific measures instead. 1
- Revaccination: If vaccinated before travel out of season, still receive current U.S. seasonal vaccine the following fall/winter. 1
Pitfalls to avoid
- Do not assume summer travel from Northern Hemisphere is low risk; cruises and opposite-hemisphere seasons increase exposure. 1
- Do not delay vaccination awaiting Southern Hemisphere product; proceed with available vaccine if SH formulation cannot be obtained. 1
- Do not conflate MERS risk with influenza vaccination indications. 1