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It's my understanding that the majority of symptoms associated with the common cold (runny nose, inflamed sinus, slight fever) are essentially the result of the immune system's response.

I've never heard of someone dying of the common cold (unlike influenza), even in immune compromised people. As such, what damage would the cold virus inflict if there was no immune response? Would it be catastrophic?

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    $\begingroup$ Related $\endgroup$ – De Novo Jan 12 at 16:31
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    $\begingroup$ Generally, you need some immune response. For the particularly bad immunodeficiencies, even something as seemingly benign as a rhinovirus will extend beyond it's preferred niche in the nose, infect the lower respiratory tract and cause death. Perhaps if I get some time I'll write an answer about this. $\endgroup$ – De Novo Jan 12 at 16:38
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Can someone die of the common cold?

No. The common cold is a clinical syndrome restricted to upper respiratory tract involvement. By clinical syndrome, I mean it is the constellation of symptoms (rather than the consequence of a specific pathogen). As you mention, these symptoms are the result of the immune response, rather than tissue damage or compromised function as a direct effect of a pathogen or its toxin (e.g., the watery diarrhea in cholera).

As defined (see, e.g., Cecil Medicine Ch. 369), this clinical syndrome cannot lead to death.

The common cold is an upper respiratory syndrome of rhinorrhea and nasal obstruction, frequently accompanied by sore throat, sneezing, and cough.

Can the viruses that cause the common cold cause death?

Yes. Many viruses that cause the common cold also cause other clinical syndromes that can cause death. This occurs when viral replication moves to the lower respiratory tract. As an example, influenza viruses are responsible for 25 - 30% of common colds (see Bennett, Principles and Practice of Infectious Disease, Ch.58). When it moves beyond the upper respiratory tract, influenza is responsible for substantial mortality. Other virus families that are responsible for both a common cold syndrome and lower respiratory tract syndrome in immunocompetent individuals (e.g., bronchiolitis, pneumonia) include parainfluenza virus, metapneumovirus, adenovirus, and (rarely) coronavirus. Rhinovirus, responsible for 40-50% of common cold cases, is uniquely unsuited to lower respiratory tract involvement, because of its preference for the cooler environment of the nasal mucosa, replicating best at 33 C (Murray Medical Microbiology, Ch 56). However, in individuals with Severe Combined Immunodeficiency (SCID), lower respiratory tract involvement does occur. There are a number of case series reporting death due to lower respiratory rhinovirus. This is an example.

Can the common cold lead to serious illnesses other than lower respiratory tract involvement?

Yes. Other morbidity can occur as a result of the immune response that produces the common cold syndrome. Rhinorrhea and congestion can progress to a viral rhinosinusitis, a separate syndrome with its own complications, or a secondary bacterial infection, which can lead to bacterial sinus involvement and/or bacterial lower respiratory tract infection. Otitis media is another common complication, especially in children, and has its own potential complications. Asthma (and, generally speaking, most lung diseases) can also be exacerbated by what would otherwise be a simple common cold and predisposes to lower respiratory tract involvement. Asthma does deserve special mention, because rhinovirus associated exacerbations can be fatal, but this is a consequence of asthma rather than a common cold syndrome. Further discussion of these syndromes are beyond the scope of the question, but are discussed briefly in the chapters referenced above.

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  • $\begingroup$ I don't think coronavirus is that rare as a cause for LRTI. "Coronavirus Causes Lower Respiratory Tract Infections Less Frequently Than RSV in Hospitalized Norwegian Children" shows that coronavirus (in particular, HCoV-OC43 and HCoV-NL63) was in 44% of the LRTI patients in the sample (of coronavirus or RSV), RSV was in 71%, and 15% had both. So RSV is more common, but not overwhelmingly so. $\endgroup$ – Charles Jan 14 at 18:17
  • $\begingroup$ @Charles look at the methods section. Those are nasopharyngeal samples, upper respiratory tract samples. Members of the coronavirus family are not typically isolated from lower respiratory tract samples. It occurs in some specific important syndromes, e.g., SARS, but the common viral families responsible for both upper and lower respiratory tract syndromes are influenza, parainfluenza, metapnuemovirus, and adenovirus. Rhinovirus are even less likely to be isolated from the lower respiratory, but, again, it does occur, especially in severely immunocompromised children. $\endgroup$ – De Novo Jan 14 at 18:35
  • $\begingroup$ @Charles Generally, be skeptical of any study that says: "look, i isolated this very common virus from the site where it typically lives. It must be responsible for this particular thing". Rhinovirus and coronavirus are also quite commonly isolated from the nasopharynx of healthy individuals. $\endgroup$ – De Novo Jan 14 at 18:43
  • $\begingroup$ Yes, the samples are collected from the upper respiratory tract, and every patient has an URTI. That's the context we're working in here: colds, which are URTIs. But some URTIs progress to LRTIs, and I gave the numbers for LRTIs. The numbers of URTIs are larger and have a higher fraction of HCoVs. $\endgroup$ – Charles Jan 14 at 18:47
  • $\begingroup$ @Charles as discussed,URI predisposes to LRI, but if rhinovirus or coronavirus cause the URI, it's typically a secondary infection by some other virus or bacteria that causes the LRI. Isolating a very common virus from the upper respiratory tract is not useful for determining the cause of a lower respiratory tract infection. $\endgroup$ – De Novo Jan 14 at 18:51
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The common cold is not the result of a single virus. Over 200 viruses can cause a cold, so specific symptoms could vary depending on the virus in question. However, in the absence of an immune response, the virus is may destroy bodily tissues as it completes its life cycle of infecting a cell, using the host cell machinery to replicate its genome, and causing the cell burst open and release the next generation of viruses. This destructive effect could lead to catastrophic symptoms. Especially since the infection is in your respiratory tract, severe tissue destruction could be fatal. It should be noted, though, that the infection generally subsides in a week even with a compromised adaptive immune system (like in HIV/AIDS). This is probably why you've never heard of people dying from the common cold, since it is likely that if their immune system is that compromised as to make such a thing possible, the cold would be the least of their problems.

Sources: https://www.cdc.gov/antibiotic-use/community/for-patients/common-illnesses/colds.html

The most common virus that causes the cold is the rhinovirus, which undergoes the lytic cycle: https://en.wikipedia.org/wiki/Lytic_cycle

clarification: as kindly pointed out by De Novo (thank you!), Rhinovirus itself does not lead to tissue destruction in respiratory epithelia. The Rhinovirus was mentioned simply as an example of the lytic cycle of viral replication, which results in the destruction (lysis) of infected cells and could result in tissue destruction.

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  • $\begingroup$ So would it be fair to say that because a lesser immune response would suffice for many common colds, e.g. those caused by Rhinovirus, the symptoms are often "unnecessarily" strong? So the immune system essentially says "better safe than sorry"? $\endgroup$ – Peter - Reinstate Monica Jan 15 at 19:45

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