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Flu has disappeared worldwide during the Covid pandemic

scientificamerican.com

591–600 of 821 posts

Re: Flu has disappeared worldwide during the Covid pandemic

#591

This should not come as a surprise, and it was largely predictable from the outset. The flu has a base reproduction number (R0) less than 2 ( https://www.vdh.virginia.gov/coronavirus/2020/12/07/covid-19... ). Covid has an R0 in the vicinity of 2.5 ( https://www.cdc.gov/coronavirus/2019-ncov/hcp/planning-scena... ). In the meantime, public health measures like masking and distancing will work against both viruses. If…

Some of this is actually a surprise - we don't have a good handle on how influenza seasonality works, and some of the "Just So" stories for it should have promoted influenza transmission, like increased indoor crowding above even the usual levels in the winter.

The dynamics of influenza could have been expected to change, and I would have put money on they decreasing, but it is never the less not pre-ordained nor attributable to an obvious cause (for example, one of the original reasons people didn't push mask orders is the limited suggestion that they were effective for flu).

Re: Flu has disappeared worldwide during the Covid pandemic

#592

Earlier quoted context omitted.

Those measures are not entirely different from the measures previously suggested, though. Obviously your quoted poster’s concerns are less about “hand washing”, “wear a mask if you have symptoms”, and “stay home” while you recover, and instead are about an overreaction in which entire businesses are forced to shut down, children without symptoms are forced to wear masks even as they run and play, and people are forci…

The normal flu can be pretty bad. In 2018 the spike in total deaths in TX and surrounding states were between a third and a half of the covid spike in those regions. Masks might have been a good idea in 2018 and I hope they become part of our culture at least when you think you might be coming down with something. You know, that first day of a cold when you are telling yourself its allergies or drainage. Shutting dow…

"Shutting down stores makes less sense."

Depends on what you want to achieve. If you like a increase of infection, you do it like here in germany and close down hardware stores etc. multiple times on short notice, without telling when they will open again - so people try to storm them before they close, all coming closely together by doing so, which they would not have otherwise.

Re: Flu has disappeared worldwide during the Covid pandemic

#593

Earlier quoted context omitted.

This year was a great experiment in person hygiene. It was the healthiest I have ever been for a full year, no colds, stomach bugs, anything. I'm not sure which practices I'll continue, but its definitely shown me that I have wayyyy more control over my health than I previously thought. Curious what others think are the most effective continued practices. Seems like social distancing isn't super reasonable, but maybe…

You can do a LOT. I haven't been sick once in 6+ years because I do the following: 1) Almost never eat out. Home cooked meals that I've prepped / washed. This was single handedly the biggest factor that completely removed "getting sick" from my life. 2) Hand wash before touching face, or food. 3) Avoid sick people. If I hear someone coughing or sneezing, I move away from them. Call me a germ freak, I don't care, I've…

Studies seem to suggest that because of the air filtration and air flow that flying is one of the safest ways to travel with other people.

Re: Flu has disappeared worldwide during the Covid pandemic

#594
post #466
post #396

Earlier quoted context omitted.

At a super fundamental level, epidemics take place on a social graph. In a well connected graph spread will be exponential, but depending on graph shape it could be something else. In particular you could imagine that if people never venture outside their own block that the social network is an euclidean graph. In an ideal case where people are evenly spaced in the plane and only interact with neighbors, the disease…

I'm perplexed why anyone would downvote this comment; it seems very interesting and insightful to me.

I'm perplexed as well. That the perfect mixing models most people think of for infectious diseases are an imperfect approximation of the actual dynamics on a graph is well known in epidemiology.

Re: Flu has disappeared worldwide during the Covid pandemic

#595
post #584

Earlier quoted context omitted.

Actually, what you're saying is untrue. The overwhelming evidence shows that children spread COVID less than adults do. My favorite is this: https://www.nejm.org/doi/pdf/10.1056/NEJMoa2006100?articleTo... The study isolated SARS-CoV-2 samples from every positive case, sequenced genome of virus, and tracked the mutation patterns. So, that will avoid a lot of the errors that improper qPCR usage can result in. First thi…

Focusing the "child" cutoff at ten seems dubious. Why not set it at an age that includes school extra curricular activities? :(

As a parent of a 6 year old and 8 year old, I'm thankful for this cutoff. Many studies define child as <= 18 or < 20, and I'm not sure how relevant they are for our particular situation.

Re: Flu has disappeared worldwide during the Covid pandemic

#596
post #387

Earlier quoted context omitted.

>> there will be considerable political pressure to "do something" about the next flu wave. This must be resisted Why on earth does it make sense to resist sensible public health measures to reduce the influenza to R0 The measures would not need to be nearly as drastic as those for COVID ("normal" R0 of 2 vs 2.5+), so more handwashing (good to minimize a broad spectrum of pathogens), masks (already culturally ordinar…

Those measures are not entirely different from the measures previously suggested, though. Obviously your quoted poster’s concerns are less about “hand washing”, “wear a mask if you have symptoms”, and “stay home” while you recover, and instead are about an overreaction in which entire businesses are forced to shut down, children without symptoms are forced to wear masks even as they run and play, and people are forci…

Most of the measures the public health community is pushing are:

- Paid sick leave. First and foremost.

- Increased flexibility for people WFH as possible if sick or vulnerable.

That's really about it. Maybe masking, though that well has been throughly poisoned.

Re: Flu has disappeared worldwide during the Covid pandemic

#597
post #271

Earlier quoted context omitted.

> This should not come as a surprise, and it was largely predictable from the outset....the flu has a base reproduction number (R0) less than 2....Covid has an R0 in the vicinity of 2.5....In the meantime, public health measures like masking and distancing will work against both viruses....there's really no need for conspiracy theorizing. Assuming that this is due to "masking and distancing" and the small difference…

Did we even test for the flu? Or did we just presume that flu cases were COIVD because the symptoms are so similar? The idea that the flu just 'disappeared' despite world trade continuing just sets off my bullshit detectors. Between all the countries that did little or nothing initially, and the people who refused to wear masks and didn't lock down...there's just no way it dropped to zero. Less? Sure. But gone? I sim…

It didn't drop to zero. "Gone" is hyperbole - it was an extremely light flu season, but it wasn't zero or anything like that.

And yes, we test for influenza a lot.

Re: Flu has disappeared worldwide during the Covid pandemic

#598

Earlier quoted context omitted.

> and the small difference in R0 is crude thinking. Given the reproduction number appears as the base of an exponent, I would not consider the difference "small." If influenza has a typical R0 of about 2, reducing contacts by 50% would make its growth non-exponential. If covid has a typical R0 of about 2.5, doing the same would require a further 20% reduction of contacts, to 40% of baseline rather than 50%. Since pop…

Small but important correction: nothing can make epidemiological spread non-exponential. Driving base reproduction below one additional infection per infected patient means the exponent is less than one, so the incidence of the disease rapidly decreases. This decrease is also exponential by definition: infection is simply an exponential process, and an exponential equation doesn't stop being what it is when the expon…

>>Small but important correction: nothing can make epidemiological spread non-exponential.

“Exponential with R varying over time” and “not exponential” differ only in interpretation imposed by an observer.

> infection is simply an exponential process

No, in the hyperidealized perfect mixing scenario, its a logistic process, like most other resource constrained processed that look exponential when analyzed over a dhort period.

In the real world, its neither exponential nor even perfectly logistic, even before considering changes to the environment in which the disease spreads (including those induced by the disease, including people’s response to knowledge of it.)

Re: Flu has disappeared worldwide during the Covid pandemic

#599
post #406

Earlier quoted context omitted.

Usually my colleagues at the office didn’t wash their hands before eating and showed not so great overall hygiene. They also missed many days due to “stomach bug”. And then there’re people with children, they’re always sick. Yes, it’s been a great year in terms of not having to deal with many people. But I have to say I’m a bit worried it’ll go back to usual soon.

I am hoping people get serious about staying home if they’re sick. “I’m not contagious.” If you’re not contagious, then how did the whole office get wiped out?

Too bad companies do have policies about this as it implies discouragement of taking sick days. Perhaps the CDC has some guidelines that help such as "stay home if you have had a fever in the last 48hours".

Re: Flu has disappeared worldwide during the Covid pandemic

#600

This should not come as a surprise, and it was largely predictable from the outset. The flu has a base reproduction number (R0) less than 2 ( https://www.vdh.virginia.gov/coronavirus/2020/12/07/covid-19... ). Covid has an R0 in the vicinity of 2.5 ( https://www.cdc.gov/coronavirus/2019-ncov/hcp/planning-scena... ). In the meantime, public health measures like masking and distancing will work against both viruses. If…

Non virologist naive question, if we apply all these measures targeting SARS-COV2 and it also creates a massive negative pressure on flu viruses, is there a risk that this applies an adaptive pressure to select for a future uber infectious new flu strain?

It's unlikely. Most of the major "uber infectious" influenza strains don't emerge via ordinary mutation (antigenic drift) but the reassortment of two viral genomes that have infected the same host (antigenic shift). Given pigs and wild birds aren't social distancing, there's no reason to believe there's a distinctly high amount of additional pressure one way or the other.
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