Fever appears to rev up the immune system

Let’s imagine you’re walking around barefoot and stub your big toe hard on the leg of a table. It hurts. That’s a pain (quite literally), but at least it’s telling you you’ve done something you might want to avoid doing too often. And should that pain persist in the form of inflammation, there’s a chance you are going to be a bit more protective of that toe while it heals. Look at it like that, and there’s an argument for seeing pain as a positive thing.

This is a simple example of how the body generates symptoms that, while inconvenient, are to the betterment of the body and the healing process. Another example is fever.

One of the normal symptoms and signs of infection is raised body temperature. I’ve read and been told several times that fever ‘helps the immune system do its job’, and there now appears to be some evidence that this is indeed the case. In a study published recently in the Journal of Leukocyte Biology, higher body temperature in mice was found to lead to greater numbers of cells known as CD8+ T cells that have the ability to kill cells infected with a virus (as well as tumour cells) [1].

This study was done in mice, but there’s a fair chance, I’d say, that similar immune enhancement would be found in we humans if we were to look.

Fever might make us feel uncomfortable, but it may well have benefits in terms of combating an infection. And if that’s the case, then perhaps we need to think carefully before we reach for the paracetamol (acetaminophen) to bring down the heat.

Very high fever can be hazardous to health, and this is particularly the case in children who may suffer from what are known as ‘febrile seizures’. However, in cases of milder fever, there’s an argument for letting nature take its course.


1. Mace TA, et al. Differentiation of CD8+ T cells into effector cells is enhanced by physiological range hyperthermia. Journal of Leukocyte Biology 2011;90(5): 951-962

12 Responses to Fever appears to rev up the immune system

  1. Asclepius 14 December 2011 at 8:49 pm #

    I can highly recommend ‘Why We Get Sick’ by Nesse & Williams for in intriguing insight into this whole area.

    They pick apart both the strategies of infection and our response to it from an evolutionary perspective (of both the pathogen and host).

  2. Kris 15 December 2011 at 1:25 am #

    I completely agree with what you are saying here.

    I’ve often wondered about the point of taking these drugs at the slightest onset of fever, since the raised temperature seems to be the natural reaction of the body.

    Headaches, however, are a different story. I can’t see any reason not to take a painkiller when you have a headache.

  3. Tim 15 December 2011 at 3:05 am #

    Hi Doc,

    This post really resonated with me, as I’ve just applied this basic principle to a totally different kind of problem.

    I just banged up my foot pretty bad while exercising. I’ve sprained both feet before and have always gone straight to the ice and anti-inflammatory meds (ibuprofen). This time I didn’t do either. Just rested it. The reasoning being that it seems to me that the acute inflammatory response (swelling, increased blood flow, etc) isn’t just some nuisance the body produces to annoy us, it’s there to heal us. Seems to me that icing and taking meds to block that process might actually be counterproductive.

    Sure enough, my recovery this time around seems remarkably faster. Not exactly a rigorous scientific study, but something to note.

  4. John Briffa 15 December 2011 at 10:26 am #


    I’ve sometimes wondered about the wisdom of the icing/elevation approach to injury on the same basis as you – should we really be suppressing a process that is designed to heal?

    Well done for being brave enough to try letting nature take its course. No, nothing scientific about this, as you say, but interesting nonetheless.

  5. DoctorM 15 December 2011 at 8:38 pm #

    At the first sign of cold or ‘flu symptoms take vitamin C, zinc and possibly echinacea and let the infection take its course – AVOID paracetemol. One won’t avoid the initial fever or increased body temperature but the supplements seem (to me and to wife) to accelerate the progress of any fever and reduce total duration – I think there have been some studies done which support this anecdotal view. If one eats a high nutrient natural wholefood diet the risk of getting such infections is of course reduced. So I agree with Doctor John and just wanted to draw attention to the possibility that natural treatments can sometimes enhance immunity and speed of recovery whereas drug treatments can may delay recovery by inhibiting the natural process.

  6. kem 16 December 2011 at 12:40 am #

    I think ice has of late has fallen from favour in the “rice” therapy acronym. I find that rest, compression and elevation (as do many others) hasten recovery.

    If I am afflicted with tendon pain (acccompanied by swelling) in a hand or wrist (from shoveling, chainsaw or swinging an ice axe) or acute joint pain in either knee (generally walking downhill) 600mg of ibuprophen at bedtime seems to work a treat. That’s just me, mind you.

  7. Christine 16 December 2011 at 2:21 am #

    My husband picked up a cold/flu virus recently and I gave him copious amounts of chai, which is a tea made with ginger, black pepper, cinnamon, cardamom and cloves. He “sweated it out” in three days flat rather than the week+ it would normally take. I’m a firm believer in fever as part of recovery.

    I have often wondered if the hot flashes of menopause are mini fever-like responses designed to help the transition rather then “symptoms” of hormonal imbalance. Any thoughts?

  8. SueK 16 December 2011 at 11:43 am #

    Hi Christine,
    Yes I’m with you there on menopause thoughts. I followed that theory for myself, cut out coffee, bottled sort and any other agrivators, negative foods and thoughts and sailed through.
    For my children and their ‘fevers’ I used belladonna; hot and tired or aconite; hot, night time dry and frightened.
    Now I have realised that the white blotch like places (along under nose and around mouth ) on a reddened face actually follow the Large Intestine meridian….. and what’s that about ? Getting rid of stuff the body does not want! Good detox happening… Let it go…. Easily…

  9. DoctorM 16 December 2011 at 1:36 pm #

    Christine, I take a famous brand Indian ‘Spiced Tea’ with Cinnamon, Ginger, Cloves, Black Pepper, Cardamon, and in fact black tea, every day ,several times a day as a routine and enjoyable protective (hopefully) measure. Also I have fresh ginger with my melon every day as well as turmeric and black pepper with protein course of meat or pulses and various other herbs and spices. Added to a diverse wholefood diet I hope this all has some protective value. We can use natural remedies to combat infections and I do so if the need arises but I can see no problem in incorporating these natural ‘treatments’ as part of the regular diet which I also do. If we can ward off rather than treat, so much the better. I think susceptibility to some (perhaps many)infections is a sign of dietary deficiency.

  10. Frederica Huxley 16 December 2011 at 5:37 pm #

    Interesting – I am recalling all the instances where I have read in 18-9th c literature “and his fever broke and he awoke refreshed” – these are the times when the body has done its job, killing off the invading pathogens. Alas, there were many times when the body lost its fight. In a similar fashion, there is a German cure for cancers which involves heating the body for short spells to kill tumors.

  11. John Duggan 19 December 2011 at 9:00 pm #

    Let me just call an exception, in the case of gout. From bitter experience of a gouty toe, I can attest that the early use of anti-inflammatories is the only way to avoid a lingering and agonizing condition. My belief is that the inflammation actually impedes the dissolving of uric acid crystals and that it is only when the swelling goes down that the body can flush out the afflicted area

  12. Norma 24 December 2011 at 11:40 am #

    I have psoriatic rheumatoid arthritis and when I have a virus my arthritis flares: usually the arthritis flare precedes my being aware that I have an infection by quite a few days. However the rheumatology nurse told me that while for many patients this is a common occurrence, for others an infection causes the arthritis to go into remission as their immune system is obviously engaged elsewhere .

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