How significant is fever in suppressing virus outbreaks?

https://www.reddit.com/r/askscience/comments/lkfqqg/how_significant_is_fever_in_suppressing_virus/

created by Theremere on 15/02/2021 at 15:21 UTC*

3757 upvotes, 17 top-level comments (showing 17)

I was recently sick in Covid 19, during the sickness i developed a slight fever.

I was recommended to not use Ibuprofen to reduce the fever since that might reduce the body own ability to fight the virus and therefor prolong the sickness

How much, if any, effect does fever have on how long you are sick?

Comments

Comment by Sys32768 at 15/02/2021 at 20:32 UTC

3029 upvotes, 26 direct replies

There are a few different views being expressed so far, but nothing comprehensive.

It's important to note that a fever is the body's own response to infection, rather than being 'caused' by the virus. (Cause and effect here is quite blurred). The body is going through it's wired response to infection, and this has been evolutionarily beneficial to humans and other species for a long time.

There are three purported reasons for fever being beneficial.

1. It kills the virus. **Not true** for reasons stated elsewhere. It's not enough of a change to cook the virus. This does seem to be an urban myth that is commonly believed though

2. It enhances immune response. **True**.

3. It prevents some viruses from multiplying or being as effective. **True**.

The complexity is that whilst fever is often beneficial in reducing mortality in different species, we have evolved alongside viruses and so viruses are not being caught flat-footed by it. Obviously natural selection in viruses is rapid and so those that survive with us now are less affected by the fever in our immune response.

Fever also has a high cost in energy use to a human, and there are some reasons why very sick people should be prevented from having a fever e.g. those in intensive care. Reducing fever has become unquestioned now, but research is being conducted into where, when and who should be allowed to run with a fever versus have it controlled. The answer to your question "How much, if any, effect does fever have on how long you are sick?" is "It depends on who you are and what you are infected with and how healthy you are generally."

It's a good question, because despite fever being so commonplace and recognised as part of our immune response for thousands of years there is no solid code of practice for answering this, and a lot of misinformation floating around.

Comment by Hiddenagenda876 at 15/02/2021 at 20:14 UTC

221 upvotes, 3 direct replies

Fever boosts the immune system itself. It enhances the production of CD8+ cytotoxic T cells, among other things, with as little as a 2 degree increase.

Source: am a microbiologist that specialized in immunology before beginning work in bio pharma.

Comment by [deleted] at 15/02/2021 at 19:17 UTC

64 upvotes, 0 direct replies

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Comment by [deleted] at 15/02/2021 at 19:35 UTC

187 upvotes, 3 direct replies

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Comment by [deleted] at 15/02/2021 at 19:02 UTC

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Comment by [deleted] at 15/02/2021 at 15:58 UTC

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Comment by [deleted] at 16/02/2021 at 00:47 UTC

12 upvotes, 1 direct replies

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Comment by [deleted] at 15/02/2021 at 17:55 UTC

21 upvotes, 2 direct replies

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Comment by TDaltonC at 15/02/2021 at 19:06 UTC

56 upvotes, 3 direct replies

Here's a good review article:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4786079/#__ffn_sectitle

"For example, the use of antipyretic drugs to diminish fever correlates with a 5% increase in mortality in human populations infected with influenza virus and negatively affects patient outcomes in the intensive care unit."

Comment by [deleted] at 15/02/2021 at 18:12 UTC

8 upvotes, 1 direct replies

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Comment by [deleted] at 15/02/2021 at 17:37 UTC

25 upvotes, 2 direct replies

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Comment by [deleted] at 16/02/2021 at 00:39 UTC

5 upvotes, 0 direct replies

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Comment by Vesane at 16/02/2021 at 12:40 UTC

2 upvotes, 0 direct replies

There's a whole journal series that's been dedicated to these sorts of Qs, called Things We Do For No Reason. Things that even we as doctors in hospital do just because it's practice that has been taught to us, and trying to challenge those knee-jerk resident tasks with actual evidence. There was one on the routine use of anti-pyrexials (like ibuprofen/paracetamol) in infection: https://www.journalofhospitalmedicine.com/jhospmed/article/221332/hospital-medicine/things-we-do-no-reasontm-treatment-infection-related-fever?channel=27621

Comment by MD-Zombie at 16/02/2021 at 13:15 UTC

1 upvotes, 0 direct replies

Sys32768, thumbs up. RE corona, check out this interesting article regarding zoonotic transmission from bats. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4012789/[1][2] Turns out, viruses incubating in bats become "tolerant" to high temperatures since the bats have a naturally fluctuating body temp, routinely getting high temps when flying.