Flying with a fever? Best not in a scheduled aircraft!

Flying when you have a temperature can be very dangerous for both you and the other passengers. During a flight the already increased risk of thrombosis increases further, a sick passenger whose immune system is weakened will find it difficult to rest on the plane, and, depending on the illness, there is also the risk of infecting other passengers. In addition, the cause of the fever may be an illness that could be aggravated by flying.

In other words, flying with a temperature is simply not a good idea – at least not in a scheduled aircraft. Below, we explain the relevant circumstances and possible consequences and suggest an alternative if a scheduled flight is not possible.

What is a fever?

Fever is an increase in the body’s core temperature which usually occurs as a natural immune response to an infection. In humans, a body temperature of 38°C (100,4 °F) or more is defined as a fever (or a high temperature). However, the fever itself is not usually a disease, but a symptom of an underlying illness. This is usually an infection, but the fever can also be caused by other things, such as a tumour.

In the first phase the patient often starts shivering (gets ‘the chills’) and feels cold. At this point, the body is sending a signal that it is cold in order to raise the body temperature. Usually, the patient reacts by wearing warm clothing and wrapping themselves in a duvet or using a hot water bottle and this also contributes to raising the temperature. The human body is normally able to limit body temperature without assistance, before it becomes dangerous. This would be the case at a body temperature of more than 41.5°C (106,7 °F).

Once the fever subsides, this process is often associated with feeling very hot, sweating and becoming dehydrated. Therefore, when you have a fever it is important to drink plenty of water to compensate for the loss of fluid.

Increased risk of thrombosis when flying with a high temperature

The risk of thrombosis generally increases during a flight. Passengers remain stationary in their seats for a long time, the cabin air is dry and most people tend to drink only a small amount of fluid. As a result, the blood becomes more viscous and blood clots, known as thromboses, can form.

If a passenger has a high temperature, these effects are sometimes even more severe. Someone who is already feeling ill or weak will move around even less during the flight than a healthy passenger. And in addition to dehydration, the fever may result in an increased requirement for fluid. Last but not least, fever is often caused by an infection, which can lead to inflammation processes in the body. This inflammation may further slow down the flow rate of the blood, increasing the risk of thrombosis.

Depending on the particular case, the consequences of thrombosis can be serious. A thrombosis in the leg can cause pain or a feeling of heaviness. It becomes even more problematic if part of the blood clot gets free and reaches vital organs. This can lead to an embolism (such as pulmonary embolism), which can be fatal. Permanent organ damage can also occur with an embolism. In view of these possible consequences alone, no one should casually board a plane if they have a fever. But there are other reasons, too.

Lack of rest during a flight

People who are seriously ill should go to bed and get plenty of rest. This allows the immune system to do its work and efficiently fight the illness. Conversely, a flight in a scheduled aircraft is very strenuous for a sick person. At check-in, the sick traveller usually has to stand in a queue; although they can sit down in the plane itself, they usually can’t lie down, and upon landing they then have to travel to their destination. In addition, at such times, the sick passenger has to deal with their luggage at both airports – possibly wrestling with heavy suitcases.

None of this is conducive to the efficient functioning of the immune system. As a result, the body is less effective at fighting the illness and it may drag on or even get worse. So patients don’t do themselves any favours if they board an aircraft when they have a fever.

Risk of infection for other travellers

But not only do patients not do themselves any favours, they also expose other travellers to unnecessary risks if they have a fever and still decide to get on board a plane. The cause of a fever is usually an infection and many of these infections are contagious. These range from quite harmless illnesses such as mild flu to life-threatening infections, which, admittedly, are now less common in Europe.

So, if you cannot rule out the possibility that the fever is caused by an infectious disease, it is extremely reckless to board a scheduled flight. After all, during a flight, you often sit close to a stranger for several hours and touch surfaces that many other passengers have already touched – for example, the toilet door handle or your armrest, on which a passenger from the previous flight has already placed their hands. It is therefore very easy to distribute your own viruses throughout the aircraft and to infect other passengers with them.

Aggravation of the underlying disease

Changes in air pressure during a flight can also negatively affect the underlying illness. Sometimes this is unpleasant, but ultimately harmless – for example, in the case of an ear infection. With ear infections, the pressure equalisation in the ear does not function properly and this can lead to severe ear pain during take-off and landing.

Other diseases such as pneumonia are affected by the lower air pressure in the cabin in a much more dangerous way. Pneumonia causes the oxygen uptake via the lungs to function less well. The lower cabin pressure in the airliner has a similar effect. When these two factors are combined, this can lead to the blood oxygen saturation of the pneumonia patient decreasing to a life-threatening level. Especially if you do not know what has caused the fever, you should avoid the risk of health complications and should not fly.

Can the airline refuse to let you on board if you have a high temperature?

Of course, the airline does not subject every passenger to a thorough medical examination before they are allowed to board. But ground personnel do look out for obvious signs of illness and routine temperature checks are not unheard of in times of COVID-19. So if a patient with a high temperature is noticeably weak, is sweating or trembling or even has to be supported, this attracts the attention of the crew. In the final analysis, it is the captain who makes the decision. Would it be dangerous to take the patient on board – either for the captain or the passengers?

The captain is only bound by his or her conscience in making this decision. There are no clear rules that bind the captain and, in particular, passengers have no automatic right to be taken on board. It can therefore be assumed that most pilots tend towards caution, as they do not want to risk any passenger’s health. In addition, a medical emergency in the air would lead to an unplanned stopover. This is not in the interest of pilots or the airlines they work for.

Alternatives to a scheduled flight if you have a fever

If flying in a scheduled airliner with a fever is not a good idea, what alternatives are there? The answer to this question depends entirely on the specific situation. If you had planned to go away on holiday or travel abroad for a business trip, you should simply postpone or cancel it. After all, it won’t help anyone if you are sick in bed at your holiday destination, and equally you should not attend a business appointment if you have this type of illness.

The situation is more complicated if you are already travelling, and the fever takes hold just before the return flight. If your illness is mild, you may be able to extend your hotel booking by a few days or find alternative accommodation for the duration of your sickness. If you are seriously ill or if the cause of the fever is unclear, you should seek medical treatment – preferably at a hospital.

If you are in a country with poor medical care, you may only want to entrust your treatment to the local doctors for as long as it is absolutely necessary. In this case, a medical repatriation in an air ambulance is your best option. In contrast to a regular airliner, flying in an ambulance aircraft when you have a high temperature is possible in most cases.

On board the ambulance aircraft, an experienced flight doctor will take care of the patient throughout the flight and can make use of the modern medical equipment in the cabin, which also enables us to transport intensive care patients. The flight doctor will take the appropriate measures to reduce the risk of thrombosis while the patient spends the flight lying on a special stretcher bed and can get some rest. There are no other passengers on board, so there is no additional risk of infection, and if the air pressure inside an ordinary aircraft would cause complications, the ambulance aircraft can perform a Sea Level Flight with higher air pressure. This means that even fever patients can be transported home quickly and safely.

Meeting the cost of an ambulance flight

The costs associated with an ambulance flight can only be calculated on an individual basis, so unfortunately we cannot provide any standard rates at this point. However, we will be happy to outline the most important contributing factors here. Of course, the flight route plays an important role, as does the precise state of health of our patient. In addition, we take into account how urgent the flight is and how many relatives will be travelling with the patient as accompanying persons. (Please note that in some cases accompanying persons are not permitted for medical reasons.) Should a Sea Level Flight be necessary, this will incur additional costs.

If you have a valid travel insurance policy that includes international health insurance, there is a fair chance that the insurance company will take over the costs. This depends primarily on whether the insurance covers only ‘medically necessary’ cases or includes ‘medically reasonable’ cases. A medical repatriation is deemed necessary if adequate treatment is not available locally. However, this is now only the case in very few countries, and for patients with particularly severe illnesses. A medical repatriation is classified as being reasonable if treatment in the patient’s home country promises better outcomes. This is true of most cases, but only a few insurance policies cover ‘medically reasonable’ repatriations.

Reasons for choosing Medical Air Service

We at Medical Air Service are the reliable partner for you if you need an ambulance flight. Our international network of state-of-the-art ambulance aircraft is ready to serve you worldwide – we can arrange a medical repatriation no matter where you are. Our multilingual staff will support you in communicating with the local medical staff and will organise the fastest possible medical repatriation for you. Our experienced flight doctors will take care of you during the flight so that you can be flown back to your home country safely, in spite of your illness. You can rely on our many decades of experience!

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