Covid-19: may be endemic

Written By: - Date published: 8:51 am, May 15th, 2020 - 53 comments
Categories: covid-19, health, International, Social issues - Tags: , , ,

Like measles, covid-19 could become endemic. Never dying out entirely. Needing to be controlled in human denser populations into the indefinite future.

This is the warning from the WHO.

Speaking at a briefing on Wednesday, WHO emergencies director Dr Mike Ryan warned against trying to predict when the virus would disappear.

“It is important to put this on the table: this virus may become just another endemic virus in our communities, and this virus may never go away,” Dr Ryan told the virtual press conference from Geneva.

“HIV has not gone away – but we have come to terms with the virus.”

Dr Ryan then said he doesn’t believe “anyone can predict when this disease will disappear”.

There are currently more than 100 potential vaccines in development – but Dr Ryan noted there are other illnesses, such as measles, that still haven’t been eliminated despite there being vaccines for them.

WHO Director-General Tedros Adhanom Ghebreyesus stressed it was still possible to control the virus, with effort.

“The trajectory is in our hands, and it’s everybody’s business, and we should all contribute to stop this pandemic,” he said.

WHO epidemiologist Maria van Kerkhove also told the briefing: “We need to get into the mindset that it is going to take some time to come out of this pandemic.”

While I’m not a doctor, over the years I have looked at the history of diseases in human populations in my reading and courses. That is where I think that this disease will wind up. If I had to bet, and assuming a vaccine, I’d say this will eventually be more prevalent than measles, and less frequent outbreaks than the annual flu. It will be endemic.

In epidemiology, an infection is said to be endemic (from Greek ἐν en “in, within” and δῆμος demos “people”) in a population when that infection is constantly maintained at a baseline level in a geographic area without external inputs.[1] For example, chickenpox is endemic (steady state) in the UK, but malaria is not. Every year, there are a few cases of malaria reported in the UK, but these do not lead to sustained transmission in the population due to the lack of a suitable vector (mosquitoes of the genus Anopheles).

Wikipedia – endemic

The difference from measles is that it seems likely that any conferred immunity getting covid-19 or from a vaccine will be temporary. Unlike measles which generally gives a life-long immunity, the corona viruses in human populations often appear to only give a few years immunity.

We simply haven’t observed this disease for long enough to be able to say that with any definition. But there is a lot of attention being paid to looking at reinfection rates, because this has obvious implications in public policy.

There is a particularly good article in the US NPR (National Public Radio) looking at different aspects of immunity with the corona virus family and with covid-19 in particular.

Antibodies, which are proteins found in the blood as part of the body’s immune response to infection, are a sign that people could be developing immunity. But antibodies are by no means a guarantee a person will be protected for life — or even for a year.

Shaman has been studying four coronaviruses that cause the common cold. “They’re very common and so people seem to get them quite often,” Shaman says. Ninety percent of people develop antibodies to those viruses, at least in passing, but “our evidence is those antibodies are not conferring protection.

That may be simply because colds are relatively mild, so the immune system doesn’t mount a full-blown response, suggests Stanley Perlman, a pediatrician who studies immunology and microbiology at the University of Iowa. “That’s why people get colds over and over again,” he says. “It doesn’t really tickle the immune response that much.”

He’s studied one of the most severe coronaviruses, the one that causes SARS, and he’s found that the degree of immunity depended on the severity of the disease. Sicker people remained immune for much longer, in some cases many years.

For most people exposed to the novel coronavirus, “I think in the short term you’re going to get some protection,” Perlman says. “It’s really the time of the protection that matters.”

Perlman notes that for some people the symptoms of COVID-19 are no worse than a cold, while for others they are severe. “That’s why it’s tricky,” he says, to predict the breadth of an immune response.

And it’s risky to assume that experiences with other coronaviruses are directly applicable to the new one.

Nadeau is working on several studies, including one that seeks to recruit 1,000 people who were previously exposed to the coronavirus. One goal is to identify people who produce especially strong, protective antibody responses. She says the antibody-producing cells from those people can potentially be turned into vaccines.

Another critical question she’s zeroing in on is whether people who become immune are still capable of spreading the virus.

“Because you might be immune, you might have protected yourself against the virus,” she says, “but it still might be in your body and you’re giving it to others.”

It would have huge public health implications if it turns out people can still spread the disease after they’ve recovered. Studies from China and South Korea seemed to suggest this was possible, though further studies have cast doubt on that as a significant feature of the disease.

Indeed…

More questions than answers so far. But as the people from the WHO have been pointing out, unlike SARS, it looks like covid-19 is unlikely to die out in the world population.

So New Zealand should probably start planning on it being present in those 4 million tourists who used to flood our shores every few years. Because after all the growth pattern for covid-19 looks like the grim reality of this graphic. It only takes a few people spreading and a reduced level of immunity in a population, and social distancing becomes the only viable public health measure.

From a question time by a virologist at the world economic forum in march

53 comments on “Covid-19: may be endemic ”

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  1. Ad 1
    15 May 2020 at 9:14 am

    The interesting conclusion out of that for me is that permanent high waves of economic damage continue to surge around the earth, decreasing only in years not months – at least until there is a globally available vaccination.

    That would mean a much longer depression of global oil production, and carbon expenditure generally.

    If this is the only way to bring forward peak oil demand, it's a dim sliver of silver lining a carbon-black cloud.

    • RedLogix 1.1
      15 May 2020 at 11:13 am

      The interesting conclusion out of that for me is that permanent high waves of economic damage continue to surge around the earth, decreasing only in years not months – at least until there is a globally available vaccination.

      Right on the first point, but many of these damage events are not going to be irreversible. Whatever emerges in the next decade is not going to be readily recognisable; in much the same way the world of 1950, would have looked quite strange to someone in 1930.

      A vaccine is not going to turn back the clock on any of this.

  2. Dennis Frank 2
    15 May 2020 at 10:05 am

    Best to think of humans as ecosystems. " The human body is teeming with microbes—trillions of them. The commensal bacteria and fungi that live on and inside us outnumber our own cells 10-to-1, and the viruses that teem inside those cells and ours may add another order of magnitude." https://www.the-scientist.com/features/the-bodys-ecosystem-37085

    "Altogether, the members of the human body’s microbial ecosystem make up anywhere from two to six pounds of a 200-pound adult’s total body weight, according to estimates from the Human Microbiome Project, launched in 2007 by the National Institutes of Health (NIH). The gastrointestinal tract is home to an overwhelming majority of these microbes, and, correspondingly, has attracted the most interest from the research community. But scientists are learning ever more about the microbiomes that inhabit parts of the body outside the gut, and they’re finding that these communities are likely just as important."

    "From a microbes “point of view” the human body is a vast array of surfaces some internal, others external that are continuously colonized by endemic and exotic microbes beginning from the time of our birth and continuing throughout life up until and even beyond the point of death. The surfaces on which these organisms grow and are constantly being sloughed off as new tissues form beneath existing ones resulting in the loss of established biofilms but providing new and uncolonized, or at least less colonized, cell surfaces on which new biofilm communities can be come established." https://www.cs.montana.edu/webworks/projects/stevesbook/contents/chapters/chapter004/section007/blue/page001.html

    "He received a PhD in microbiology from Michigan State University and postdoctoral training in Ecology at the University of Chicago." 15 min talk on The Human Body as an Ecosystem: Brendan Bohannan at TEDx: https://www.youtube.com/watch?v=Dfy2qYfUWE0

    For those in a hurry, this one is quick & posted last month: https://www.gutmicrobiotaforhealth.com/a-video-for-understanding-why-were-like-an-ecosystem/

  3. ianmac 3
    15 May 2020 at 10:59 am

    Ouch!!!

  4. McFlock 4
    15 May 2020 at 11:30 am

    If we can manage it so that it truly is comparable to influenza (i.e. even a short term vaccine means vulnerable people can get a free jab every year), tourism can open up again imo.

    But I reckon we might want to consider in the meantime what tourism we allow – cruise ships? Package tours? Tourist density?

    • Sabine 4.1
      15 May 2020 at 12:00 pm

      the question might rather be………whom we allow in. Where does the tourist come from. any place on this planet will be as safe as is the weakest link, atm i would say that would be England, Europe, US. – and a lot of our tourists come from there.

      • McFlock 4.1.1
        15 May 2020 at 12:22 pm

        Not if we have regular immunisation and quick-process tests at the border.

        But assuming we can reopen, we do have an opportunity to avoid oversaturation. To put it bluntly, tourists might bring in cash but they're also a big problem, from congestion to pollution.

        • Sabine 4.1.1.1
          15 May 2020 at 2:04 pm

          so far we have neither.

          • McFlock 4.1.1.1.1
            15 May 2020 at 4:03 pm

            possibly a good idea to start mulling it over now, though.

            Otherwise it'll just be the last 40 years all over again, operators maximising their little patch and bugger the consequences for everyone else.

    • weka 4.2
      15 May 2020 at 12:35 pm

      Mass, fast tourism is not compatible with a low carbon economy, why even go there in terms of trying to recreate it?

      • McFlock 4.2.1
        15 May 2020 at 12:59 pm

        Indeed.

        But the place is awesome and people want to see it. So do we blanket limit numbers of visas? Maybe charge a premium for tourist visas? Or do we look at what tourism industry practises we allowed to evolve that maybe we should rethink – bus package tours? Maybe a hundred-mile limit for bus charters? What about cruise ships (fwiw, I have a real issue with that industry)? Airbnb vs domestic housing?

        The tourist industry as we know it is dead. But tourism will grow again, and it can either be left to evolve to accrue the greatest buck while throwing off negative externalities like before, or we can plan it more carefully this time,

        • weka 4.2.1.1
          15 May 2020 at 1:33 pm

          My suggestion is that we separate tourism from the economy. Create sustainable jobs to provide livelihoods for locals (which may or may not be in tourism, but let genuine sustainability/regenerative economy be the guiding principle).

          Then look at the borders issue. I'm fine with them staying closed for now. That tourists like it here doesn't mean they should get to come. It's not that we should never have tourism, it's that we're not in a position yet to design a new system that takes into account covid (too many unknowns atm), or climate/ecology.

          A hundred-mile bus limit might be a useful tool, it's just not the start of the design process, it's more like nearer the end.

          The issue of how to earn export income to buy all our things likewise could be seen now through a sustainable lens. Instead of starting with the fear that if we don't have extractive industries we can't have health care or iphones or margarine, what if we looked at what we actually need once we're relocalised what we can due to covid and future proofing against other disasters and pandemics? Then look at how we earn the money or generate the wealth to support those things we truly need and want.

          • weka 4.2.1.1.1
            15 May 2020 at 1:36 pm

            Also, I'd love to see research done on how locals feel about mass tourism if they had the choice of making a good living in other ways (this is distinct from the industrial tourism powerholders). Because what I'm hearing is that lots of people are relieved to have their backyards back to normal after the past few decades (even people that are new to areas can feel this), and I'm betting that there will be flow on mental health benefits from things not being so damn crazy all the time.

            "NZ" might want the tourism industry back, but do the people who live in the high tourism areas?

            • weka 4.2.1.1.1.1
              15 May 2020 at 1:37 pm

              Might be good to look at the values benefit in tourism too not just the dollar value. We might find some conflict between going for big buck tourism and say cultural exchange.

          • McFlock 4.2.1.1.2
            15 May 2020 at 4:09 pm

            What does "separate tourism from the economy" mean? By its very nature it's an economic beast.

  5. Sabine 5
    15 May 2020 at 12:02 pm

    at the very minimum i would expect the next three to 5 years to be very interesting.

    I would also suggest that poeple might start getting used to the idea that life is that vulnerable that within three weeks from today one can be dead. It was intersting to check the dates/duration/death number of previous pandemics, Justinian Plague – 4 years, half of the world population dead ( known world population) same as with the plague in 1360 – 4 years, half of the world population dead…Maybe we should keep this in mind.

    • lprent 5.1
      15 May 2020 at 8:17 pm

      Bearing in mind the rate that we have been getting novel viruses out of Africa, Asia, and the Middle East in the last 4 decades as those areas develop and push into animal reserves, I think that we can expect to get at least two or three pandemic threats each decade.

      • Sabine 5.1.1
        17 May 2020 at 10:02 am

        i think the reason we will 'get' these pandemics has more to do with the 'developped aka rich' worlds travel to places and then bringing with a whole heap of stuff we did not pack, such as mosquitos, and yes, viruses.

        It is interesting to read up on the strains, and the Covid Strain that did NY and NJ in is the one from Italy, where lots of people travelled in February for their Carnevale / summer holidays.

        A bit like in the dark ages when the pestilence was brougth to Europe by returning crusaders and the fleas in their clothes, travel packs etc.

  6. weka 6
    15 May 2020 at 12:39 pm

    The bit I don't get yet is whether NZ can technically eliminate the virus completely or not.

    If we look at the SDHB figures, there haven't been any new cases in something like 4 weeks. There are a small number of existing cases (poor sods, this means they've been ill for longer than a month, and this is another emerging issue that's not well understood yet). If those existing cases were quarantined and the DHB borders closed, assuming for the sake of argument these are possible and desirable, then isn't it a matter of time until there is no coronavirus left in that area?

    Or, are we assuming that there is still de facto community transmission, it's slower than expected, and it's not yet visible?

    • Poission 6.1
      15 May 2020 at 1:13 pm

      Or, are we assuming that there is still de facto community transmission, it's slower than expected, and it's not yet visible?

      No one really knows,whether it can remain in a dormant state in known reservoirs( in nz humans, and cats,few bats)

      The ability to be asymptomatic (whilst still shedding virus) then become symptomatic suggests an opportunistic predator.

      Today the marist cluster case is a good example.

      Today's confirmed case is linked to the Marist cluster in Auckland and was identified through recent follow-up testing of the school community.

      The Ministry said the person who tested positive first had symptoms nearly two months ago and had a previous negative test.

      https://www.rnz.co.nz/news/national/416713/one-new-case-of-covid-19-in-new-zealand-after-three-days-of-no-cases

      • weka 6.1.1
        15 May 2020 at 1:26 pm

        "No one really knows,whether it can remain in a dormant state in known reservoirs( in nz humans, and cats,few bats)"

        Thanks, that's the missing link I think. Do we know how this works with other viruses?

        The Marist situation might have been a false negative or someone who didn't have covid 2 months ago but has since picked up it up elsewhere.

      • Incognito 6.1.2
        15 May 2020 at 2:01 pm

        They said it was a “weak positive”, which suggests to me it was at the lower end of the test range, possibly close to the sensitivity limit. They also stated that this person was “not considered infectious now” but on what basis is not clear.

        • Poission 6.1.2.1
          15 May 2020 at 2:32 pm

          Lots of unknowns,

          sensitivity.test methodology change.CV mutation etc.

          Too little knowledge means the risk have not changed,the signalling needs to remain vigilant.

          • Incognito 6.1.2.1.1
            15 May 2020 at 2:45 pm

            Agreed.

            The test is in all probability still the same as used all along unless there’s batch variability in the kit or instrumentation, which is also highly unlikely but still possible. We would have heard about a change in testing methodology.

            I don’t have information at hand, but the PCR test is meant to be robust and insensitive to mutations. It seems unlikely that after previously testing positive, then negative, and now ‘weakly positive’ that this was caused by a mutation.

            The most likely ‘explanation’, IMHO, is a different sample taken by a different practioner and/or a false negative in the previous test.

            No cause for alarm but also no reason to become complacent and lackadaisical.

  7. Treetop 7
    15 May 2020 at 1:04 pm

    Covid-19 is not just endemic but like a hole in a bucket when it comes the economy.

    I wonder if Robertson and Bridges had a money box as a kid and who saved the most.

    The 20 b extra borrowed needs to be saved for the stormy days. What those stormy days are going to be no one can predict when and how severe. I have always said that having money in a crisis allows a person to have more options.

    The government have done a good job in preventing a crisis and by crisis I mean a high death toll.

    • Stunned Mullet 7.1
      15 May 2020 at 3:01 pm

      'The government have done a good job in preventing a crisis and by crisis I mean a high death toll. '

      I must admit to be less enthralled with their efforts, than with our very fortunate position in being a small, sparsely populated country a long way from COVID-19 hotspots.

      • Treetop 7.1.1
        15 May 2020 at 3:54 pm

        It takes a hell of a lot more than a geographic location of a country to prevent a Covid-19 slaughter.

        The PM could have been like the President in Brazil or Trump or Johnson who were not prepared to go hard and fast.

        I am jittery about our border being opened up to non citizens and non residents due to the sneakiness of the virus.

        • Stunned Mullet 7.1.1.1
          15 May 2020 at 4:30 pm

          Comparing us with North America in particular and Europe to a large degree is fairly facile.

          Both countries had COVID 19 circulating much earlier than we did to the extent that when they did take action there was a very large amount of community transmission occurring it is more apt to compare ourselves to our nearest neighbor.

          • Treetop 7.1.1.1.1
            15 May 2020 at 5:08 pm

            What other countries do is up to them. I am not into the comparing game. I am into seeing the virus eradicated in the country I live in.

        • Janet 7.1.1.2
          15 May 2020 at 4:39 pm

          “I am jittery about our border being opened up to non citizens and non residents due to the sneakiness of the virus.”

          Me too. Covid 19 needs to be fully understood before we open our borders wide again.

          Had the money been spent earlier in quarantining – however which way – and controlling the “left too late stampede” to NZ, after Covid19 had really started to move, we would be in a much better economic situation now. Like , almost normal, except for no tourism; and yes I am glad to have our country back from the tourists.

          As usual we must look to our good land and concentrate on farming. I would like to think it becomes more organic and sustainable, which would engage a lot more people in producing livestock and horticultural products. As usual farming is the most economical way we produce exportable products to pay for only the NECESSARY imports we require.

          • Treetop 7.1.1.2.1
            15 May 2020 at 5:31 pm

            Closing the border any sooner could have caused an up roar. There had to be evidence to show that community transmission was occurring for people to wake up.

            It is reassuring to know that in NZ a person will not go hungry unless they cannot afford to purchase food. As for being able to acquire most items they could be produced here. Medication and medical equitment would need to be imported along with vehicles.

            A BIG rethink on tourism is required as no one wants a tourist to be a carrier of a virus which can be so destructive. The days of tourism being good economically are gone until Covid-19 is fully understood.

            As a side issue 36 million people are now unemployed in the US and medical workers are being laid off and their health insurance is being stopped, reported on Aljazeera TV today. The lines of motor vehicles queuing for food was in the 100s.

            There is a lot to be grateful for in NZ even with the hard times many people are going through.

      • McFlock 7.1.2
        15 May 2020 at 8:45 pm

        I'm getting a bit fed up with the "sparsely populated" line that serves only to minimise our efforts (and I mean everyone in the country).

        Sure, we have a low overall population density, but we have a higher urbanisation rate that the UK and USA, so it's not like we're evenly spread with 18 people and a hundred sheep each square kilometre.

        We've had a lot of good luck, to be sure: off the beaten track enough to get our community infection a little bit later than other nations (this gave us time to learn from the mistakes of others) and a competent leadership, for example.

        But with different leaders (and yes, it might just be down to thanking Winston for choosing Labour/Greens) or a bunch of imbeciles listening to a semi-literate cheeto, we'd be pretty much as fucked as UK/USA/Italy and counting our dead by the hundreds or even thousands.

        We could have all gone to the fucking beach but no, we fucking did the work. Putting it all down to luck or popul;ation density screws everyone out of their share of credit for hard work, not just the government.

        • weka 7.1.2.1
          15 May 2020 at 9:13 pm

          totally agree. And going forward too, all the effort being put into contact tracing and making work places and public places safer.

        • Stunned Mullet 7.1.2.2
          15 May 2020 at 9:16 pm

          Sigh… different (NZ) leaders would make little difference, we followed the pandemic plan as directed by the Ministry of Health.

          The majority of our clusters and cases were down to returning travellers. You will note most of the greatest infection and loss of life overseas has cluttered around high density population and spread from there.

          Probably our greatest piece of luck was that the cruise ship that disgorged multiple carriers in Sydney didn't do the same thing in downtown Auckland.

          In a couple fo years time the global public health officials will be able to look back and see what has been the most appropriate response to this virus I expect that sealing off an area prior to significant introduction of viral carriers and then greatly decreasing human interaction will feature strongly.

          • McFlock 7.1.2.2.1
            15 May 2020 at 9:37 pm

            We had a good pandemic plan, but one that still had to be adapted. It didn't include the concept of elimination, for example.

            Leadership is not irrelevant. Would Bridges or Blinglish have gone for lockdown too late, or come out of it too early? Probably not as badly as bojo or the yank, but the nats would have been more vulnerable to industry whinging than the coalition, I think. Not to mention Collins at the cabinet table. And would either of the BBs have communicated well enough to keep NZers on the same page, or would we have seen more noncompliance ruining it for everyone? What about the review of contact tracing – would the nats have commissioned and embraced a critical report, or would they have allowed institutional push-back and argued everything in that area was ok? There were multiple action choices like that, and the government chose correctly most of the time, enough to make us world leaders.

            I don't for one minute think the nats would have been as bad as bojo or the yank, but there's an exponential penalty for failure in this situation. that means their outcomes could well have been closer to a UK than our current toll.

  8. ianmac 8
    15 May 2020 at 1:06 pm

    On a personal scale I sympathise with the disaster facing the Tourist trade given that good conscientious workers will be unemployed. But the damage to the Environment and infrastructure makes me totally unsympathetic to the Industry. Especially their spokespeople shouting for Government/taxpayers support in spite of the terminal nature of their plight.

    A bit like feeling sympathy for the top All Blacks but being anti the Tour.

    • Dennis Frank 8.1
      15 May 2020 at 1:24 pm

      Yeah, the bleating. Capitalism is based on a boom & bust cycle – thought everyone knew that. The tourist industry has had the boom & have now entered the bust. Get real time. Whining about the size of the govt handout just demonstrates petulance. They deserve to have the govt appoint David Seymour to lecture them in person about market forces & the benefit of discipline…

    • weka 8.2
      15 May 2020 at 1:27 pm

      I have little sympathy for the big players and the industry leaders. It's not like climate change is a secret or new and they've been as bad as industrial farming in terms of resisting reality.

    • Treetop 8.3
      15 May 2020 at 1:37 pm

      There are limits on what the government can do to help a business survive. The government cannot become a silent partner and bail out a business which relies on tourists when there are no tourists. Anyone who loses their job deserves sympathy and a benefit to survive.

    • mpledger 8.4
      15 May 2020 at 5:26 pm

      When ever I went to tourist destinations, the workers were invariably young overseas visitors. It will be interesting to see how may unemployed NZers were in the tourist industry.

      We really have to encourage the young and the fit to take a hit for the country and do some of the crappy jobs that bring in export dollars – horticulture, agriculture etc. Maybe if we can give them some other reward for putting their career aspirations on hold e.g. free tuition at uni/polytechs for every year of doing crappy jobs.

  9. Pat 9
    15 May 2020 at 1:27 pm

    Given we are daily learning about this virus the thought had crossed my mind …what if there is an as yet unrealised impact on fertility?

    • Stunned Mullet 9.1
      15 May 2020 at 3:05 pm

      With around 300k births per day globally that would be a global boon albeit an individual tragedy.

    • Treetop 9.2
      15 May 2020 at 3:14 pm

      Not just fertility but a healthy pregnancy. Due to the virus not being around in its current form for more than six months, so much is unknown.

      Even transmission at birth is a high risk. Not a good start for a mother and the baby.

      • Incognito 9.2.1
        16 May 2020 at 12:12 am

        Women with HIV can have healthy babies without infecting them. A HIV test is done when pregnant.

        • Treetop 9.2.1.1
          16 May 2020 at 9:57 am

          Antivirals have proven to have a good outcome for HIV. This is also wanted for Covid-19.

          A vaccine or an effective treatment is needed for Covid-19.

          • Incognito 9.2.1.1.1
            16 May 2020 at 11:58 am

            Agreed. Three things though: 1) HIV infection/disease is preventable and manageable; 2) it has taken a long time to develop an effective treatment for HIV; 3) HIV cannot be cured although there are a couple of reported cures, apparently, after stem cell transplantation.