Distinguishing between the COVID-19 pandemic and influenza pandemics (A/H1N1, A/H2N2, A/H3N2): a narrative review, 2026, Daodu et al.

[Chandelier]

Distinguishing between the COVID-19 pandemic and influenza pandemics (A/H1N1, A/H2N2, A/H3N2): a narrative review

Daodu, Lanre Peter; Yusuf, Omolola Olabisi; Okouzi, Methodius

Abstract​

The COVID-19 pandemic is frequently compared to historical influenza outbreaks, yet this analogy often obscures fundamental biological and epidemiological divergences.
As the global health community confronts new threats like H5N1 avian influenza, a rigorous retrospective analysis is essential to distinguish the unique trajectory of SARS-CoV-2 from the influenza pandemics of 1957 (H2N2), 1968 (H3N2), and 2009 (H1N1).
This narrative review, adhering to best-practice guidance, synthesises literature published up to mid-2025.

We performed targeted searches of PubMed, EMBASE, and WHO/CDC archives to compare SARS-CoV-2 critically and Influenza A across virological, clinical, and sociopolitical dimensions.
Our analysis reveals that while both pathogens share respiratory transmission, they differ starkly in evolutionary mechanisms and systemic impact.
Virologically, SARS-CoV-2 utilises convergent evolution and broad ACE2 tropism to cause multi-organ pathology and long-term sequelae (Long COVID), distinguishing it from the primarily respiratory effects and reassortment-driven shifts of influenza.
Epidemiologically, SARS-CoV-2 exhibits a significantly higher basic reproduction number (R0), rising from ~ 2.5 to > 9.5 in Omicron variants, and substantial asymptomatic transmission, necessitating non-pharmaceutical interventions of unprecedented scale compared to the modest measures of past flu pandemics.
The public health response also highlighted a divergence in medical innovation: the development of mRNA vaccines within 11 months represented a “quantum leap” in vaccinology compared to the slower, egg-based timelines of 2009.

In conclusion, COVID-19 represents a distinct biological and societal entity that defies the historical “flu template.”
The transition to endemicity, marked by year-round waves of immune-evasive variants like JN.1, and the current emergence of mammalian H5N1 underscore the need for pathogen-agnostic preparedness.
Future global health security depends on leveraging the genomic and technological assets developed during COVID-19 to counter threats that transcend historical expectations.

Web | DOI | PDF | Bulletin of the National Research Centre

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[Jonathan Edwards]

They conveniently leave out that Covid19 was probably man made, rather than 'evolved'.

 

[Chandelier]

They conveniently leave out that Covid19 was probably man made, rather than 'evolved'.

This documentary was eye‑opening in showing me how some Chinese scientists can pursue their research with no regard at all for ethical concerns:

 

[Jonathan Edwards]

This documentary was eye‑opening in showing me how some Chinese scientists can pursue their research with no regard at all for ethical concerns:

As I understand it the Chinese scientists were hired by US and UK organisations to do their dirty work away from scrutiny.

The thread post says video not available. Maybe I am outside your zone of scrutiny @Chandelier !

PS It says my YouTube history is off. Whatever that means.

 

[Chandelier]

As I understand it the Chinese scientists were hired by US and UK organisations to do their dirty work away from scrutiny.

Interesting… and after years of denial of any human involvement the intelligence agencies start to point towards China.

The thread post says video not available. Maybe I am outside your zone of scrutiny @Chandelier !

Ah, too bad. This trailer should be accessible worldwide. The climax is around 1:40min:

PS It says my YouTube history is off. Whatever that means.

You are probably not logged in or the watch history has been disabled in the settings.
Nothing to worry about.

 

[jnmaciuch]

They conveniently leave out that Covid19 was probably man made, rather than 'evolved'.

Probably because the scientific evidence of that is quite weak, based on poor modeling and bad assumptions, and the political evidence even moreso. I got a pretty good rundown of those assumptions spending a large chunk of the last year on viral genomics projects. An animal reservoir was never required to explain Sars-CoV-2, the evolution from previous human-circulating coronaviruses was well within normal evolutionary leaps, the furin cleavage site that people claim was "engineered in" is a feature of many viruses in that family. Lots of things are theoretically possible but if this is a science forum we ought to make assertions like that on actually good evidence, no?

 

[ScoutB]

An animal reservoir was never required to explain Sars-CoV-2, the evolution from previous human-circulating coronaviruses was well within normal evolutionary leaps

Do you know where I could read about this angle? Is the idea that covid's precursor just circulated as a mild cold for a long time until it happened to become more virulent? Would we expect to be able to find relatives of it then?

 

[jnmaciuch]

Is the idea that covid's precursor just circulated as a mild cold for a long time until it happened to become more virulent? Would we expect to be able to find relatives of it then?

Depends what you mean by precursor and relatives. MERS is technically an ancestral relative and has a much higher mortality rate than SARS-CoV-2. But yes in all likelihood the "precursor" to SARS-CoV-2 was probably a milder virus. The initial claims of it coming from bats were due to sequence homology in certain regions of the viral genome, but every analysis of viral ancestry is always a a statistical inference based in several assumptions. Sometimes those assumptions hold up well, especially when you're modeling viral evolution within one host. But the idea of viruses making big leaps in a short period of time has always been known. Just between SARS-CoV-2 variants there's ongoing debates about the role of prolonged infection and coinfection in immunocompromised hosts possibly allowing a leap like omicron to "evolve" out of a single person.

So it's possible that we did already have sequencing data of the closest relative, our models just didn't recognize it as such. There's also the issue of gaps in surveillance--we can only do that statistical analysis on samples that are available. If a virus took some big leaps in a population that wasn't being actively and diligently sequenced, it can absolutely look like certain changes came out of nowhere.

As for accessible reading material, you might have to look for reviews that talk about possible origins published after 2022-2023ish and dive through citations. I think people were falling over themselves to write them for a few years

 

[SNT Gatchaman]

See eg thread Genetic tracing of market wildlife and viruses at the epicenter of the COVID-19 pandemic (2024, Cell)

 

[Jonathan Edwards]

Lots of things are theoretically possible but if this is a science forum we ought to make assertions like that on actually good evidence, no?

The circumstantial evidence I have seen is at least good as a 'pretty good run down' from some virologists with a vested interest in would say. And the US authorities came to the conclusion it was likely an escape.

 

[jnmaciuch]

And the US authorities came to the conclusion it was likely an escape.

Yeah, several reasons to take that with a hefty grain of salt

The circumstantial evidence I have seen is at least good as a 'pretty good run down' from some virologists with a vested interest in would say.

If it’s pretty obvious to a non-virologist who spent time learning the basic principles—principles which well predate SARS-CoV-2 and were not even picked up in the specific context of COVID originally—maybe it’s worth taking a step back from interpretation of “circumstantial evidence” without even those basics. Lest we forget the ease and confidence with which exercise physiologists will come to silly conclusions about immunology and vice versa, for example

If you have special access to secret circumstantial evidence that I and many others have not already seen I’m all ears

 

[Jonathan Edwards]

If you have special access to secret circumstantial evidence that I and many others have not already seen I’m all ears

No it is the evidence everyone is aware of, including the guy who wrote a novel predicting what would happen in Wuhan. There are all sorts of ways of being blinkered.

What is not in doubt is the culpability of US and UK and probably other Western governments in supporting experiments in China deliberately increasing virulence in conditions without adequate safety precautions.

I see people at UCL still doing this. It is about time the public realised just how irresponsible scientists are in doing stuff to get Brownie points without being too bothered if a million people die.

 

[Liie]

They conveniently leave out that Covid19 was probably man made, rather than 'evolved'.

Do you know where I could read about this angle?

See eg thread Genetic tracing of market wildlife and viruses at the epicenter of the COVID-19 pandemic (2024, Cell)

Yeah, several reasons to take that with a hefty grain of salt

In order not the detract this thread any further I made a post in a separate thread linking some information which I found credible.

 

[rvallee]

Virologically, SARS-CoV-2 utilises convergent evolution and broad ACE2 tropism to cause multi-organ pathology and long-term sequelae (Long COVID), distinguishing it from the primarily respiratory effects and reassortment-driven shifts of influenza.

Several studies have shown similar outcomes from flus and other viruses. In fact, that was used by many to loudly argue that nothing should be done about LC, bizarrely, rather than that more should be done overall, since medicine is completely impotent at handling all of this. I don't understand how medical research is supposed to work, they just ignore anything that doesn't fit with the narrative they want to present, and no one seems to care.

How come we know this? And not those researchers? And the reviewers? And the editors? And everyone else involved in the production of research papers? It's not just that cherry-picking is a problem, it's basically a standard. Anything inconveniently counterfactual is either ignored or dismissed because reasons.

It really seems as if it doesn't involve biological samples in a lab, medical research is just... bad. When it does, it can be borderline miraculous, and it seems to me as if this just makes it easier to overlook the fact that the vast majority of the research published in this discipline is straight up garbage, the brightest lights shining so strong that all the dark shadowy pits get lost in the mix.

 

[jnmaciuch]

No it is the evidence everyone is aware of, including the guy who wrote a novel predicting what would happen in Wuhan. There are all sorts of ways of being blinkered.

Oy vey. It is no surprise whatsoever that a pandemic would eventually emerged from a region with ripe conditions for cross-species hopping in proximity to a dense population center. Lab or no lab. Shall we award someone a medal for predicting a disastrous earthquake at some point in San Francisco or Chile

What is not in doubt is the culpability of US and UK and probably other Western governments in supporting experiments in China deliberately increasing virulence in conditions without adequate safety precautions.

All governments are culpable for emergency pandemic preparedness, especially considering that a coronavirus with with increased virulence and lower mortality than MERS enabling farther spread is exactly what any viral epidemiologist would have been wary of from natural evolution.

Because as I keep saying, there was nothing about SARS-CoV-2 that was surprising for a virus of its lineage to develop. The main evolutionary leap—a furin cleavage site—would have already been in its genetic code with a few nucleotide changes rendering it non-functional until stochastic processes and evolutionary selection made it functional again. Which again, is well within the bounds of normal but unfortunate viral evolution that governments should have been better prepared for. So the “circumstantial evidence” explains nothing

It is about time the public realised just how irresponsible scientists are in doing stuff to get Brownie points without being too bothered if a million people die.

Sure, but maybe we ought to focus on things we’re more sure they actually did instead of yelling at clouds