COVID-19 (SARS-CoV2) Pandemic: Epidemiology and Prevalance

by Raywat Deonandan, PhD

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    00:00 The total number of COVID tests done around the world as of October was distributed according to this graph, on a country to country basis. Every country does it differently.

    00:12 Testing is key.

    00:14 Absence a cure, a treatment, or vaccine testing is the best strategy for containing the epidemic.

    00:22 because if you can identify people who are ill, you can prevent them from infecting others.

    00:28 So, Singapore was the world leader for a long time in doing testing.

    00:33 Other countries struggled to keep up.

    00:35 So the countries that do strategic and thorough testing tend to have a better grasp on the spread of the epidemic.

    00:43 Singapore and Iceland have done a good job.

    00:47 The total confirmed cases exploded quickly in the first six months of the disease from the end of February up until October.

    00:56 So, we got to about 35 million cases in those seven months, between March and October.

    01:06 And now, two months later, we're at over 80 million cases.

    01:12 So, that is a case of exponential growth.

    01:15 Number of deaths are also increasing.

    01:19 The COVID cases by country in the first nine months of disease are presented in this graph.

    01:24 This is useful for showing where the clustering seems to be taking place.

    01:28 And not surprisingly, the most crowded largest countries are having the worst experience with this disease.

    01:38 Total confirmed deaths are of course, the most troubling statistic.

    01:42 From March to October, we saw a rapid rise in deaths to the point where we have a million deaths at the end of October.

    01:51 But here we are at the beginning of January, and we're closing in on 2 million deaths.

    01:54 So, it took seven months to reach 1 million deaths.

    01:57 And just over two months to reach another million deaths.

    02:01 That is a sign of exponential growth in death as well.

    02:09 COVID-19 has a disproportionate effect on individuals with certain pre-existing conditions.

    02:17 And by disproportionate, I mean you're more likely to be hospitalized and more likely to die if you have certain conditions.

    02:24 Number one, is age.

    02:26 The elderly are far more likely to die of this disease.

    02:31 That's why it's burning through long-term care centers.

    02:33 And that is why we must focus so much of our attention on preventing the disease from entering the domain of the elderly.

    02:42 Cardiovascular disease, diabetes, people are undergoing steroid therapy, the obese, the hypertensive, these are conditions that predispose you to having a very bad experience with this disease.

    02:55 In many ways, this disease is shortening the timeframe of bad outcomes.

    03:02 Typically experienced by those experiencing chronic diseases, shortening that timeframe to make it resemble an acute experience.

    03:11 In other words, perhaps your diabetes or your obesity would have killed you in a few decades.

    03:17 But now it's going to kill you in a few weeks because of COVID-19.

    03:21 Pandemics have a way of shortening timeframes, and for making chronic diseases appear acute.

    03:34 So, what are the challenges to COVID-19? Well, we have this very high transmission rate.

    03:40 Some people argue over the lethality of the disease, but it is a fairly lethal disease when compared to things like the seasonal flu.

    03:50 The infection fatality rate is probably somewhere between 0.5 and 1%.

    03:56 And for seasonal flu, it's around 0.1 or at the most 0.2%.

    04:02 But even if we're as equivalent.

    04:04 The fact is COVID-19 is so much more infectious, that it affects a great many more people, therefore, a larger number of people will be hospitalized and die.

    04:15 So, high transmission is troubling.

    04:20 It is, in large part an asymptomatic epidemic.

    04:24 This really confounds our ability to contain it and control it.

    04:28 Because...

    04:31 just because you have no symptoms doesn't mean you're not infectious.

    04:38 So, this long incubation period is a great confounder.

    04:42 The vaccines are a scientific miracle, to be sure.

    04:47 But they don't yet have high penetration.

    04:49 As a result, they cannot be relied upon as the great panacea.

    04:54 We cannot vaccinate as quickly as the disease can spread.

    04:59 If the forest is on fire, you cannot outrun the fire.

    05:03 You have to put up breaks between you and the fire.

    05:06 You have to try to put out some of those flames.

    05:08 That's why these public health endeavors to slow transmission are more vital than ever, even though we have a vaccine and we are doing our best to roll it out.

    05:19 The high hospitalization rate is of course troubling.

    05:22 Because when combined, all these factors mean COVID-19 has a high probability, a high potential to rapidly overwhelm any healthcare system.

    05:35 So, this is not just about one disease, it's about one disease having the downstream ability to destabilize an entire healthcare system.

    05:45 When all of the health care workers are focused on combating and treating people, struggling with COVID-19, other care does not get done.

    05:55 Cancer screening does not get done.

    05:58 Mental health care does not get done.

    06:01 Proper care for people showing up requiring acute urgent care is not as good because other health care workers have been taken off of those roles to give critical care elsewhere, to the COVID wings.

    06:17 So, we have in many places, cancelled, elective surgeries.

    06:22 And when I say elective surgeries that gives the impression that these are optional or frivolous endeavors but they're not an elective surgery can be someone who needs a knee replacement, to go back to work.

    06:33 They need that knee replacement for their economic wherewithal.

    06:38 So, this disease is an enormous threat to the infrastructure of many societies.

    06:46 The challenge is not overwhelming the health care system.

    06:50 This is a chart showing the projection in the province of Ontario and Canada for how COVID-19 might have affected us.

    07:00 So, in green, we see the actual cases observed up until April.

    07:05 In blue, we see the best case scenario. right? So, if we were to introduce the strongest restrictions on human contact to drive transmission low, we will still see a rise in cases plateauing around April.

    07:21 The worst case is, we fail to enact those procedures, and the cases explode out of control plateauing, at a very high level, easily overwhelming the healthcare system.

    07:34 So, this kind of projection was implemented in order to know the intensity and extent of public health endeavors to put into place to slow transmission.

    About the Lecture

    The lecture COVID-19 (SARS-CoV2) Pandemic: Epidemiology and Prevalance by Raywat Deonandan, PhD is from the course Pandemics.

    Included Quiz Questions

    1. Asymptomatic carriers
    2. Symptomatic carriers
    3. Treated patients
    4. Recovered patients
    5. Younger patients
    1. Positive exponential growth graph
    2. Pie graph
    3. Bar graph
    4. Negative exponential growth graph
    5. Scatter plot graph
    1. Age over 70 years
    2. Age under 1 year
    3. Respiratory rate of 18/min
    4. Decreased ejection fraction
    5. BMI under 23 kg/m2
    1. Singapore
    2. South Korea
    3. Italy
    4. Turkey
    5. India

    Author of lecture COVID-19 (SARS-CoV2) Pandemic: Epidemiology and Prevalance

     Raywat Deonandan, PhD

    Raywat Deonandan, PhD

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