World news – Why is coronavirus not killing as many people?

0
7

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume.

For the first time in two months, Australia has finally recorded a day with no deaths from coronavirus.

It’s a huge milestone after Victoria’s second wave pushed Australia’s national COVID-19 death toll to more than 800.

While Australia’s second wave is coming to an end, in Europe case numbers are again increasing.

But unlike last time, the death rate doesn’t seem to be going up with the number of cases.

And Norman and Tegan talk about an interesting pre-print study that has found the number of COVID-19 infections in Australia could be much higher than previously thought.

References:A dual antigen ELISA allows the assessment of SARS-CoV-2 antibody seroprevalence in a low transmission setting

Tegan Taylor: Hello, this is Coronacast, a podcast all about the coronavirus. I’m health reporter Tegan Taylor.Norman Swan: And I’m physician and journalist Dr Norman Swan. It’s Wednesday, 16 September.Tegan Taylor: So Norman, some good news in Australia. It seems to be that the number of deaths from coronavirus is dropping, and in fact yesterday Victoria had no recorded deaths for the first time in about two months. So is this reduction in deaths here in Australia a sign of things to come or is it maybe just a blip?Norman Swan: No, what you’re seeing here is the end of the second wave in Victoria, and it’s just fantastic that we are seeing the numbers of people dying going right down. As you say, it might go up and down little bit, but it will be very, very low from now on.Tegan Taylor: Is the death rate dropping, the rate of people dying compared to the number of people who have the disease at all?Norman Swan: I think you’ve got to look overseas for that rather than in Australia, and it’s not easy to calculate, as we’ve said many times on Coronacast, because it depends on the proportion of the population being tested. And we really only know the accurate infection fatality rate from things like cruise ships, the Ruby Princess, the Diamond Princess and so on, because the rate of testing varies so much from country to country.But people who’ve looked at this still think that the death rate is around about 0.4%, 0.5%, and that’s roughly what we’ve been talking about, maybe 0.6% in the past. It’s likely that it’s staying roughly the same, but in some countries it does look as if it’s dropping a fair bit, even in relation to the testing.Tegan Taylor: If you look overseas, the number of cases is increasing but the death rate doesn’t seem to be following suit. What’s happening there?Norman Swan: Well, one of the reasons is almost certainly that older people are changing their behaviour, keeping themselves to themselves. So while there might be parties in Malaga in Spain and people are going out and having a good time, it tends to be younger people doing that and older people are tending to socially distance, that seems to be the way it’s going in Europe and elsewhere. So there is a change in behaviour in people who are the most vulnerable.The other reason it’s changing this is that they’ve got much better at treating moderate to severe COVID-19 disease. So they are nursing people on their tummies, they are not jumping into ventilation as quickly, and they are using dexamethasone which reduces mortality rates in people who have got severe disease by about 20%. So things are getting better in terms of the treatment. And I think all those things together have reduced the mortality rate from COVID-19, but at considerable cost.Tegan Taylor: So part of it is a true reduction in death rate if we are getting better at treating them, but old people can’t just lock themselves up forever. How long are they going to keep this self-correction up for?Norman Swan: Well, that’s crystal ball stuff, we don’t know that, but there is a little bit of evidence now that that locking themselves up isn’t working as well because as young people get these large numbers of infections, in some of the countries they are starting to take them home and their parents and grandparents are starting to get the disease. So that low mortality rate that you’re seeing now may well not last.Tegan Taylor: We actually have a question on this from Rob, which we’ve kind of covered little bit but just in the interests of closing the loop, Rob is asking; with the numbers of positive cases in France, Spain and so on increasing rapidly and few deaths, did the first wave just kill all the vulnerable? Are we seeing a case-demic now instead of a pandemic?Norman Swan: No, it certainly didn’t. If you just look even in Sweden where it was really bad in aged care homes, luckily it did not kill all the vulnerable, there are still plenty of vulnerable people alive. And remember, vulnerability can just equal being over 70 or 80.And there is another issue here too which is the accuracy of death certificates and whether we are attributing all the deaths to people who actually died of COVID-19.Tegan Taylor: So definitely not an excuse to let our guard down.Norman Swan: No, and it could well see an uptick. And that’s the feature of this pandemic, is that you can’t relax, you can’t change what you do because it will come back to bite you. Israel thought they were invulnerable, obviously the Spanish did this, French and others, and they are paying the price for that.Tegan Taylor: So another thing that we’ve talked about on this podcast a few times and some months ago even was the amount of coronavirus that is maybe spreading undetected in the community, and there is some new research that is up on a preprint service are not peer-reviewed yet from the Australian National University that tries to quantify this here in Australia.Norman Swan: Yes, what they did was…it’s quite interesting, they did, if you like, a double antibody test. So rather than just looking for the antibodies to the spikes around the coronavirus they took another part of the virus as well, so they took two parts of the virus and looked for antibodies to both, and what they found was when they did that they got a very accurate result in terms of whether somebody had been infected. They tested it in a couple of hundred people, and then what they did was they took blood samples from people having elective surgery, nearly 3,000 blood samples, and analysed those to see what the rate of past COVID-19 infection was in them or the SARS-CoV-2 virus infection was in them.And when we talked about this before, I quoted I think it might’ve been Iowa or Utah, maybe it was Iowa, I can’t remember exactly, but a state in the Midwest of the United States which found that there were 10 times as many infections when they did this kind of study as had been recorded.And in fact what this research showed was that there has been a fairly low level of infection. This is only up to early July, by the way, it doesn’t include the second wave in Victoria. Up until then, which was really the first wave of infection in Australia, only 0.2%, 0.28% of people in Australia, if this is a valid study of these 3,000 people and these 3,000 people are representative, probably not entirely representative because they were having elective surgery, but nonetheless these 3,000 people, nearly 0.3%. Now, that doesn’t sound like much and it’s not compared to, say, parts of New York where it might be 10%. So we’ve done pretty well to keep it down to 0.28%, but that’s still about seven times as much as we recorded. So I think at the time when they finished this study there had been 11,000 cases diagnosed in Australia, and if everybody who had been infected, according to this study, had been tested, they would have had well over 70,000, almost 80,000 people infected. So there’s a lot more people who have been infected than the cases in people who have come forward for testing have suggested.There is another study been done by the Kirby Institute which is on pathology samples. I think this that will be a much larger study. It will be interesting to see what that comes up with. I think their hypothesis in the beginning was that it might be double or four times the rate, but this is a pretty high amplification, and it shows you what you’ve got to worry about here in Victoria which is that if there is a hidden number, and there will be in Victoria, as there will be in New South Wales and elsewhere, if there is a hidden number there added on, then there’s more virus circulating then you know about. And it’s quite likely also that people who died have not been accurately documented as having died with COVID-19 infection. There are probably more people who have died than have been registered as dying of the disease.Tegan Taylor: So a question from Sam, Norman, about the AstraZeneca vaccine, the Oxford vaccine. Sam is asking; when will the proposed AstraZeneca vaccine complete phase 3, if it’s successful of course, and be sent to regulators? And from there, how long does it take for the regulators to approve it?Norman Swan: Well, I think you’ll find that the regulators of the Food and Drug Administration in the United States and other regulators will do this hyper-quickly and examine the data very quickly. So they could actually look at this data in a matter of days and come to a conclusion, so that’s not going to take very long.When will they complete phase 3? That’s the unknown factor because you’ve got to recruit the 50,000 people, they’ve actually got to be infected with the COVID-19 virus and you’ve got to see that result. And the longer it takes them for them to be infected with COVID-19 and compare the placebos with the active vaccine, that’s what is going to take the time. So it’s really not certain how long that will take, to be sure.The other thing I’ll just say quickly, on this week’s Health Report podcast you can hear Professor Bruce Neal talking about one of the reasons why they may not have broadcast the reasons around this woman’s side effects, is that you can…and it’s exactly the question we had yesterday about the nocebo effect, is that people start expecting those side-effects and it can pollute the trial, so that’s one reason why they keep it quiet. But he agreed that some transparency would be needed.Tegan Taylor: So that’s the woman who had the health event that paused the trial briefly last week. You say that they’ve got to be infected with the virus. How do they measure that? Because they don’t infect them on purpose, do they.Norman Swan: No, they watch them very closely, they see whether or not they’ve got illness and they test them regularly. I’m not quite sure whether everybody has an antibody test at some point, I have no idea really how they are going to do that. I can take that as homework and come back to you on that. But there’s got to be a combination of people reporting illness, being tested and maybe routine testing of everybody at the beginning and at the end.Tegan Taylor: Well, that’s all we’ve got time for on Coronacast today, but don’t forget you can leave us a review on Apple Podcasts if you like because we love reading them.Norman Swan: And we also love your questions and they are what prompt the discussion, so go to our website, abc.net.au/coronacast, and click ‘Ask a Question’, and mention Coronacast so we can find it. Tegan Taylor: We’ll see you tomorrow.Norman Swan: See you then.

Do you have a question about coronavirus? Tell us what you want to know and we’ll try to provide you with answers.


SOURCE: https://www.w24news.com

Donnez votre point de vue et aboonez-vous!

Votre point de vue compte, donnez votre avis

[maxbutton id= »1″]