Source: Virginia Department of Health

by James A. Bacon

I have seen considerable discussion on the internet recently about the relationship between COVID-19 and influenza. One thing that seems to be widely accepted is that influenza receded — indeed it practically disappeared — as COVID-19 surged. Where the disagreement occurs is over why influenza faded and now seems to be making a comeback.

The conventional wisdom is that the masking and social-distancing measures enacted to slow the transmission of COVID-19 also acted to slow the spread of influenza. That makes intuitive sense given that the measures were designed to fight influenza epidemics in the first place and were dusted off out of desperation to “do something” about COVID-19. If the conventional wisdom is correct, we would expect to see the relaxation of masking mandates under the Youngkin administration lead to an increase in reports of Influenza Like Illnesses (ILIs) compared to the normal seasonal pattern.

An alternative theory making the rounds is that the COVID-19 and influenza viruses compete with one another. COVID-19 triggers temporary immunological responses that suppress the flu. As COVID-19 advances, the flu retreats; as COVID recedes, the flu advances.
Both theories seem plausible to me, and I don’t have the epidemiological chops to support one over the other. But I have been inspired to ask, hey, what’s the story here in Virginia? According to Theory #1 above, Virginia is kinda, sorta social distancing right now, but Youngkin’s reversal of mask mandates in schools should boost the incidence of influenza compared to last year when masking/social isolation was more rigorously practiced. Likewise, there should be a divergence between school districts that drop the masks compared to districts that contest Youngkin’s ban on mask mandates.

According to Theory #2, Virginia is experiencing a spike in COVID-19, which means that the population is building up massive natural immunities that not only confer resistance to COVID-19 in the future but should protect people from the flu for a time.

Here’s the chart for COVID-19 “hospitalizations,” a much more reliable indicator of trends than “confirmed cases,” which are heavily influenced by the availability and frequency of tests as much as by the actual prevalence of the disease.

COVID hospitalizations are up in January, as seen in the graph immediately above, but after rising in December, reported ILIs are down in January, as seen in the graph atop this post. That pattern seems more consistent with Theory #2 than Theory #1. But I’m hesitant to draw broad conclusions based on three weeks of data.

Perhaps we can make these predictions: if Theory #1 is correct and masking/social isolation is a driving factor in the incidence of the flu, then we should expect Youngkin’s rollback of mask mandates to contribute to at least a modest increase in ILIs through the flu season. If Theory #2 is correct and the Omicron surge contributes widespread temporary resistance to the flu, we should see a reduction in ILIs.

I’ll try to remember to follow up in a month and see which way things shake out.

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8 responses to “COVID Vs. the Flu”

  1. DJRippert Avatar

    How does the government know the prevalence of the flu? When I’ve gotten the flu I stay in, drink fluids and try to stay away from people. I can’t remember ever taking a “flu test”. I know I never reported having the flu to any governmental organization.

    I also strongly suspect that mandatory and, more importantly, voluntary “social distancing” kept down the flu, as measured by hospitalizations and deaths. Many people who normally go out a lot to eat and socialize have stayed home over the last two years. For COVID vulnerable people (especially the elderly) this social separation has been extreme.

    1. LarrytheG Avatar

      I would imagine if someone ends up in the hospital, they’ll know if they have the flu, no?

  2. walter smith Avatar
    walter smith

    Didn’t our illustrious government decree that a new test was necessary by January 1 of this year because the PCR test could not distinguish between the FFF (Fauci Funded Flu) and regular flu? Like back in June?
    And how come there is a category like ILI?
    Does this not imply that cold viruses constantly mutate?
    So why did the world have to end for this one?
    Asking for a friend…

  3. Nancy Naive Avatar
    Nancy Naive

    So, why don’t the OTC pill manufacturers put an auger (1/2 spiral will do) in their bottles so that turning the bottle will bring pills out one at a time?

    Flu is nowhere near as contagious, and masking, social distancing and santizing did the trick. If Covid hypes the immune system against the flu, then hell, let’s go to Florida. Maybe Hep-A will keep them both away?

    Or… the comorbid condition was the flu. It took both simultaneously to kill you!

  4. Virginia Project Avatar
    Virginia Project

    systematic misdiagnosis due to financial incentives has poisoned all the relevant data sets

  5. Nancy Naive Avatar
    Nancy Naive

    “Your comet was 65 million years too early.”
    “Hey! I was just following instructions. Seee, it says right here on the napkin, ‘Destroy dominant life form.’ If He didn’t mean immediately, then He should have said so.”
    “What else ya got?”
    “I dunno. How about a fast mutating virus?”
    “They have vaccines now”
    “Yeah, but most are too stupid to take it. Dominant, sheesh.”

  6. I’ll go with the lowered exposure due to covid measures, rather than the competing viruses, theory — the simplest explanation wins (“Occam’s razor”) except with conspiracy lovers.

  7. LarrytheG Avatar

    this is how studies get started initially, but then they have to set it up, determine all the relevant influencing factors, try to compensate (hold fixed) for all factors except those effects you want to see, then publish, then wait for one or more others to replicate/confirm or challenge.

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