5.5 Traveller Health, Vaccination Planning & In-Flight Wellbeing

5.5 Traveller Health, Vaccination Planning & In-Flight Wellbeing

Required vs Recommended - and the Line a Consultant May Not Cross

A required vaccination is a condition of entry: the state refuses admission without documentary proof. Yellow fever under the International Health Regulations is the classic case, and Saudi Arabia's meningococcal ACWY certificate for Hajj and Umrah pilgrims has the same legal character even though it sits outside the IHR certificate list - it must be dated at least 10 days before arrival and be within five years for the conjugate vaccine or three years for the polysaccharide version, and without it a pilgrimage visa is refused.

A recommended vaccination is medical advice, not law: hepatitis A and B, typhoid, rabies pre-exposure, Japanese encephalitis, tick-borne encephalitis, cholera, and routine boosters such as MMR and tetanus. No border officer inspects them; the traveller simply carries the risk.

The consultant's rule is describe the framework, never prescribe the medicine. You may say: "Bolivia may ask for a yellow fever certificate on some routings, and several other vaccines are commonly advised for Amazon-basin travel - please see a travel-health clinic or your doctor at least 6 to 8 weeks before departure." You may not name a vaccine, a dose or an antimalarial. The six-to-eight-week lead time matters because multi-dose courses (hepatitis B, rabies, Japanese encephalitis) take weeks to complete and because certificates carry their own waiting periods.

Malaria and the Diseases With No Certificate

Malaria is transmitted by the night-biting female Anopheles mosquito, and there is no vaccination certificate for it - it can never be "cleared" at a border, which is precisely why consultants forget it. Risk is mapped below national level and varies by season and altitude: a country can be high risk in a lowland delta and risk-free in its highland capital, so "is Kenya a malaria country?" is the wrong question. Protection rests on two pillars a consultant may describe generically: bite avoidance (repellent, covered limbs at dusk and dawn, insecticide-treated nets, air-conditioned rooms) and chemoprophylaxis, preventive medication begun before travel, taken throughout and continued after return, whose choice and duration are strictly a prescriber's decision. Advise clients that any fever within a year of return - especially within three months - is a medical emergency until malaria has been excluded.

Dengue, Zika and chikungunya are carried by the Aedes mosquito, which bites in daylight, so dusk-and-dawn advice alone is inadequate. Zika carries a specific pregnancy advisory: because of the risk of congenital abnormality, health authorities advise pregnant travellers to avoid outbreak areas and couples to observe a waiting period before conception after travel. Refer for the detail; do not quantify it yourself.

Food, Water and Altitude

Travellers' diarrhoea remains the commonest travel illness, and the mnemonic still holds: boil it, cook it, peel it, or forget it - sealed or boiled water, no ice, no salads rinsed in tap water, no unpasteurised dairy, nothing held lukewarm on a buffet. Suggest oral rehydration salts in the medical kit.

Acute mountain sickness (AMS) must be flagged on any itinerary that gains altitude quickly by air - Cusco at about 3,400 m, El Alto serving La Paz at about 4,060 m, Lhasa at about 3,650 m. Headache, nausea, insomnia and breathlessness typically begin 6 to 12 hours after arrival above roughly 2,500 m. The advice is itinerary design: build an acclimatisation night lower down, keep day one light, and warn that fitness offers no protection. Descent is the definitive treatment.

The Cabin Environment

Airliners are pressurised to a cabin altitude of up to about 8,000 ft (2,438 m), which is why the airline medical form asks the physician whether a 25% to 30% reduction in the ambient partial pressure of oxygen would affect the patient. Two consequences follow. First, trapped gas expands by up to about 30%, so recent abdominal, chest, eye or middle-ear surgery, an untreated pneumothorax, or a heavy head cold becomes a real problem; barotrauma - blocked ears and sinus pain on descent - is the everyday version. Second, cabin humidity commonly sits below 20%, so dehydration is genuine: recommend water, moderation with alcohol and caffeine, and spectacles rather than contact lenses.

Deep vein thrombosis (DVT). The WHO WRIGHT project (WHO Research Into Global Hazards of Travel) found that journeys longer than four hours by any mode roughly double the risk of venous thromboembolism, while absolute risk stayed low - of the order of one case per 6,000 long-haul journeys in the study population, rising with journey length and repeat flights. Higher-risk profiles include previous thrombosis or a clotting disorder, recent surgery or hospitalisation, active cancer, pregnancy and the postpartum period, oestrogen therapy including the contraceptive pill, obesity and older age. Generic prevention advice is safe to give: move every two to three hours, do seated calf and ankle exercises, keep the footwell clear of bags, stay hydrated. Compression stockings and any medication are a clinician's call.

Jet lag is circadian desynchronisation, and direction matters: eastward travel shortens the day and is harder to absorb than westward travel. A workable strategy is to shift bedtime by an hour a day for two or three days before departure, reset the watch to destination time at boarding, seek daylight in the destination morning after eastward flights and in the late afternoon after westward flights, and treat day one as a light day. The rule of thumb is roughly one day of adjustment per time zone crossed.

Diving and surgery intervals. After scuba diving, dissolved nitrogen must off-gas before the body ascends to cabin altitude. Divers Alert Network consensus guidance is a minimum preflight surface interval of 12 hours after a single no-decompression dive, 18 hours after repetitive dives or several days of diving, and substantially longer after dives requiring decompression stops; many operators simply apply a blanket 24-hour rule. The commercial consequence is concrete: never sell a last-morning dive before an afternoon flight home. Post-operative intervals vary by procedure and carrier and must come from the airline's medical department, not the agent.

Medical Clearance, Oxygen and Pregnancy

Where a condition may be affected by flight, the process runs as follows:

1. Identify the need at booking and insert the SSR MEDA in the PNR.
2. Issue the MEDIF (Medical Information Form, IATA Resolution 700 Attachment B). Part 1 is completed by the passenger or agent; Part 2 by the attending physician, covering diagnosis, stability, oxygen requirement in litres per minute, ability to sit upright, mobility, escort and any equipment carried.
3. Return the completed form to the booking carrier's medical department.
4. On an interline itinerary, the data is transmitted so that every carrying airline clears the passenger, not just the first.
5. Act on the decision: clearance with conditions (oxygen, escort, stretcher, specific seat), or refusal - in which case rebook, defer, or arrange medical transport.

A passenger with a stable permanent condition may hold a FREMEC (Frequent Traveller's Medical Card), which records the clearance and avoids repeating the MEDIF for every booking. In-flight oxygen is never assumed: some carriers supply it for a fee on request, others require an approved portable oxygen concentrator with battery documentation, and both need advance notice.

Pregnancy carriage limits are set by each carrier, not by IATA, but the common pattern is refusal beyond 36 weeks for an uncomplicated single pregnancy and beyond 32 weeks for a multiple pregnancy, with a medical certificate required from about 28 weeks, frequently dated within 10 days of departure. Any complicated pregnancy triggers a MEDIF at any stage, and individual routes can be stricter. Verify the operating carrier's published policy rather than quoting a general figure.

Accessibility requests ride on the same discipline: enter the correct SSR at booking rather than at check-in, state the precise level of assistance needed, and reconfirm before departure. Where the need is medical rather than purely logistical, the MEDA/MEDIF route applies in addition to the SSR.

Sourcing and Documenting the Advice

• WHO, International Travel and Health - the global reference on disease risk and vaccination policy.
• National health authorities - TravelHealthPro/NaTHNaC in the UK, the CDC Yellow Book in the US, and the client's own ministry of health.
• IATA Travel Information Manual / Timatic, health section - what the border will demand, which is a different question from what the doctor recommends.
• The operating carrier's medical department - the only authority on fitness to fly.

Documentation closes the loop. Record the date advice was given, the sources cited, the referral to a travel-health clinic, and the client's response - including a refusal to attend. That note is the agency's defence when a client later insists nobody told them.