Are viruses alive?

The question of whether viruses are living or not always provokes lively discussion. On TWiV 59 we decided to take an informal poll of our listeners on this issue. Let’s open up the poll to readers of virology blog.

This survey had been online since November 2009 and had collected several thousand responses. SurveyMonkey decided to delete all of those, so we are starting over as of January 2013, using a different survey site.

As of November 2013, the second survey site decided to charge users and simply deleted our data without asking. I’m leaving this page up until I find another survey site, mainly because there are quite a few comments below that I don’t want to lose.

In January 2014 I added a new poll. Let’s see how this fares.

Pick one:
  • me

    Megan and Roblage are good examples of a typical virus and parasite.

  • me

    Sounds like my ex boyfriend. Glad to have shed myself of that virus! I won’t be hosting that party anytime soon and because it happened, I now have immunity as it will never happen again…

  • me

    become a scientist and think for yourself. 

  • Ed Rybicki

    I teach my students that everything they think of as being alive is in a continuum of complexity – which goes from molecules at one end, to high-end eukaryotes at the other. Deciding just where to pitch the emergence of the properties we choose to associate with the phenomenon we call “life” depends very much on just which set of properties you like.

    I caution all the leaf-counters and snake-chasers – sorry, plant and animal science folk – that their definitions are unnecessarily detailed, and in any case would exclude things with the potential for life – like frozen embryos, seriously desiccated seeds, viruses….

  • Ed Rybicki

    Mycoplasma genitalium is a parasite. It needs a host to replicate itself. A tapeworm is a parasite. It needs a host to replicate itself…sorry, your argument falls down.

  • Marcin

    Alive = able to multiply/reproduce…

    I have another question, though. We are told that there are ‘good’ and ‘bad’ bacteria (e.g. in the stomach).

    Are there ‘good’ viruses?

  • Marcin

    Alive = able to multiply/reproduce…

    I have another question, though. We are told that there are ‘good’ and ‘bad’ bacteria (e.g. in the stomach).

    Are there ‘good’ viruses?

  • Critchers28

    Even at a GCSE level we learn that life is defined by the abbreviation MRS GREN

    M = Movement
    R = Reproduction
    S = Sensitivity
    G = Growth
    R = Respiration
    E = Excretion
    N = Nutrition

    I don’t think anything has changed in terms of defining life. Virsuses do not fulfil any of these aspects wholly.
    Yes, you could argue that they move … I’d say that they get moved.
    They reproduce? …. No, their replication is dependent on the host that they find themselves within.
    Grow? … They are built in the host, pieced together.

    I see no evidence that they are ALIVE as we define life, nor do they ever die … They simply lose their viability to cause a successful infection … Or more aptly put, they lose viability for a cell to take them in and replicate them

    An analogy (weak it may be) could be me giving you a piece of paper I’ve written on [the virus] and asking you to copy it AFTER rain has smeared all the ink [loss of viability]

  • Suzemac

    Life yes but not as we have defined and limited itd parameters

  • Betyrodgal

    Please, can somebody tell me what happens with the viruses and parasites that are in the vegetables, after blending them with a powerfull Vitamix in a delicious juice?
    Thank you

  • Tony

    Ed – there’s no reason to suppose  that matter is not infinitely divisible, if that is the case then it seems rather arbitrary to start off from molecules of it and work up to eukaryotes etc does it not?

  • Ji-hyun Lee

    That’s the point! what I wanna say!

  • Ji-hyun Lee

    That’s the point! I think that it is unclear that what the hell living organism can be described to. we have a big 4 characteristics of life such as grow, respond to stimuli, metabolite energy and reproduce the offspring to transfer its genetic information and makes their exisistence persistant. blablabla.
    But those point are just promised characteristics used to define the concept of living organism. I think that view is too rough.
    in the nanoworld, the microenvironment of the viruses, ‘we’ or other hosts are another environment to them. Actually this debate “is the virus living or non-living” comes from the point that they can not have that 4 ruled-characteristics outside of the host cell. But I think this creature resembles a plant seed or bacterial endosome that has dormancy period until it meets the apropriate requirement and suitable environment.
    virus makes many life phenomena to almost all of lives as they evolve sooooooo much long period even longer than others. I think it is alive.
    this kind of debate is just come from the narrow view that is too biased to other macromolecular wolrd.
    we say that the “cell” is the basic unit of the life, but the cell itself  can not satisfy that our ruled characteristics of life too. Of course we cannot say that the all of the molecular complex that has nucleic acid  can refer to the living organism although we say our genomic information is stored in the sequences of the nucleic acid bases. Also we do not say the viroid or prion is alive even they affect our life phenomenum.
    But I THINK it is REDICULOUS that we define something between living and non-living. How can we say something it is sometimes alive and sometimes dead?
    it is just problem of the viewpoint. if we throw away of our haman(or the other organisms)-centered view and recognize we are the environment of other creatures, we can say the virus is living thing.

  • Martín Bonfil Olivera

    I think there’s a fifth possible answer missing: the dichotomy alive-not alive is not appropriate in the  case of sub-cellular assemblies of  biological molecules like viruses…

  • Another Face

    Life is any system which has a beginning, an end, and has the capability to, at some point in its cycle, create more life. 
    Examples of life:
    Human Beings

    Note: Sterility is not a disqualifier from life since such a creature can still create other forms of life just not ones of its own species.

  • Blueduckofhell

    Define death and in relation to life of any subject. meaning to be or not to be. Here today gone to morrow. viewed and viewer. maybe your looking at a part of something much larger in it’s scope to understand the part itself time may tell or death.

  • Osamabinladne

    A virus is a complex chemical reaction

  • Ed Rybicki

    Well, I would have to worry about sentient quarks…B-)

  • emre

    What is the life? This is the main question and we didn’t describe it still.But we can say the viruses are living deads


    Is clear that the viruses are Zombies xD

  • RamaRama

    As we all know the viruses are not alive, not dead, they are kind of strange creatures. They do not have cell structure, metabolism and reproduction out of the host. However they have genetic material and can reproduce and mutate inside the host. Generally, it is better to consider them as active (not alive) inside the host and inactive (not dead) out of the host.

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  • Hannah

    It would help if you added a link to this directly from the TWiV page. I didn’t remember what episode you mentioned it on, so I ended up having to search a bit to find the poll.

  • redbee47

    If viruses are not living, then how do they evolve or move? What gives them the ability to find different cells in the body? I don’t know about you but I’ve never seen any non living mass move on its own. I can’t say that they are living either. they cannot reproduce on thier own and they don’t produce energy or take it in. Is there somewhere inbetween living and non living? If so that is where I would place a virus.

  • Squirell

    Virus continuously evolve…I think there is the answer.

  • Ken Li

    Viruses are like cars, they function but are dead. They need living interactions to function.
    ex. Viruses can only attach to and infect cells if and only if the cell contains some sort of bonding mechanism for the virus to attach. like reaching out your hands to grasp the key, the cell is reaching out its proteins to pull in the virus.

  • Kartik

    It all depends on how you define life/living..

  • Elena

    Its like shrodinger’s cat!

  • Claire

    the objective of a virus is to kill you, so it must be a living ‘mechanism’ in order to have that intention ……..and a very evil mechanism!

  • Francis Longtrowser

    that’s cool

  • Dirk Diggler

    Dude, that was an absolutely brilliant analysis! Wow, I’m still sitting here trying to wrap my head around it. Very deep! And bonus points for working in the “gay lifestyle” stuff!…Dirk …

  • Dirk Diggler

    Ouch! Sounds like you really got burned by that guy, huh? Or are you still burning from him? Perhaps he left you with a virus? One that you’ll never shed?…Dirk …

  • Dirk Diggler

    …and I just fell down when I read the word “genitalium” in your reply. Kudos to you for pooping out that word, bro! 😉 …Dirk …

  • Sean Kromer

    Dude, I was just thinking the same thing! LOL But then I thought about it some more, and it dawned on me: This is by far the most civilized, intelligent, and deeply insightful reply section I have ever seen. Every reply section should read like this! What has happened to intelligent debate?

  • Dirk Diggler

    Natural selection will take care of your love child – the unvaccinated love child of you and your HIV-positive former boyfriend. Yes, I know what you did last summer. And I’m not the only one. Your ex-boyfriend has a loose tongue, and word is spreading faster than AIDS…Dirk …

  • Peanut Butter

    Welcome to the Matrix!

  • Kyle

    Best comment so far!

  • Bobo Chan

    I don’t think viruses are alive. According to Cell Theory, we say that cell is the basic unit of all organisms. It is clear that viruses don’t possess the characteristics of a cell as it doesn’t even have the protoplasm. It is just a thing with a protein capsid enclosing some nucleic acid. Some may argue that viruses do satisfy the seven characteristics of living things (growth, reproduction, nutrition, excretion, irritability, respiration, movement), however, a virus can’t carry out any of the above outside the host cell. Hence, I think that virus can’t be regarded as a living thing.

  • Mia

    I think that viruses particles/virion (viruses in the extracellular state) are “non-living” because they’re inert; they don’t replicate/grow, don’t feed, don’t move, don’t respire and don’t response to stimuli either. But viruses inside host cells (viruses in the intracellular state) do replicate and adapt by undergoing mutation or variation, so I would say that intracellular viruses are “living”.

  • Jacob

    Yeah… no.

  • Jacob

    Why does something have to be either “living” or “non-living?” It’s a false dichotomy that is produced from only allowing the aforementioned two to exist in the paradigm. Certainly, there is some matter that clearly shows characteristics of life (cells), while there is also matter that clearly shows no characteristics of life (metal rods). Viruses share some of the traditional characteristics of life such as organization, adaptation, reproduction (kind of), and probably a few others. Labelling a virus in either extreme is fallacious.

  • claranadim

    So what?
    so do many other parasites, such as Trypanosoma, fleas, mosquitos and many worms and tons of bacteria (of course, not all bacteria is pathogenic). Yet there’s no discussion on whether they are alive or not. And if you think there should be, I’ll give you the reason why I think it’s pointless: Every single thing we are sure to call alive is interacting with a bunch of other living and non-living things, exploring the same resources and environments. A host and its natural mechanisms within it are also resources for them, though not designed (and by “designed” I mean selected because it was useful for the organism who carried the genes of it) for that purpose. Or actually any purpose.
    What differs viruses from the “sure-living” things are the facts that 1) while they’re not interacting with a host cell they don’t present any form of metabolism and 2) when they are actually infecting the cell is impossible to define the space it occupies. I never thought thins second argument was important to define life, until I read this essay by Koshland Jr, D. E., published on science (or at least on its website) in march 2002, called The Seven Pillars of Life. I absolutely recommend everyone interested in the matter to read it (:

  • claranadim

    you are aware that it’s the scientific name of that species, right? and that it’s name was given due to the fact that it inhabits the ciliate epithelium of the genital and respiratory tract of primates

  • claranadim

    …as do we

  • Jhon Barnes

    Im confuse! For me virus is a living organisms in a way that its still alive even thought its not doing anything unless get connected to its host. A non living things even though you put a host on it nothing happens. Unlike with viruses its alive inside and waiting for its host. A simple explaination without using scientific terms for us to understand clearly. Its my own opinion.


    Viruses have been described as “organisms at the edge of life.” Overall, it is considered that they are not alive, although there is no unanimous agreement. Viruses resemble other organisms in that they possess genes and evolve by natural selection can. It can reproduce by creating multiple copies of themselves through self-assembly. However, viruses do not have a cellular structure, generally regarded as the basic unit of life. Moreover, while reproducing, and require no metabolism of a host cell to replicate and synthesize new virus. However, some bacterial species, such as Rickettsia and Chlamydia, organisms are considered although they are unable to reproduce outside a host cell.

    One possible approach is to consider living to those who use cell division to reproduce, compared with viruses that assemble spontaneously. This establishes the analogy between viral autoesamblado within host cells and autonomous growth of crystals. However, the autoensambldo of viruses has implications for the study of the origin of life because it gives credence to the hypothesis that life could have begun by self-assembling organic molecules.

    Considering that viruses are alive, the question could be expanded to discuss whether smaller infectious particles, such as viroids and prions, are alive.

  • sampanna

    just imagine you are the virus and ask to yourself that i am alive or dead and you will get the answer.
    also try to be the rock, or tree and ask to your self am i alive or not and you will get the answer.
    i believe everything in this earth has life.

  • Doofus

    I believe they bridge the gap between living and non-living.

  • Doofus

    That’s one of the three main debated theories, actually. Good point.