Practical Prevention Strategies, Patient Age vs. Case Fatality Rate (Lecture 28)
Welcome to another MedCram covid-19 update. We’re going to talk today again about the numbers, about the epidemiology. We’re actually going to talk about the case fatality rate and the age specifically. A lot of you have asked about how age effects that.
We’re also going to talk about testing. There has been some interest in how we test for SARS COV-2, and in light of what we talked about last update, which is what the sensitivity and specificity were, we talked about how the sensitivity of the kits that have been made public and available in certain situations is not the best. We will also go to talk about healthcare workers, and this all sort of ties in together.
Here is the Johns Hopkins dashboard. Total confirmed 80, 389; total deaths 2858; total recovered is 36, 563. These are the numbers that are being put out by the various organizations.
Moving over to the Worldometer coronavirus cases. And if we exclude the Chinese numbers, we can see here that we are definitely in an epidemic phase outside of China. And if we look at the pie chart, we can see here that that slice of the pie is definitely growing, and I think you can expect that that is going to grow even more here in the next number of weeks.
If we look at the number of cases outside of mainland China, a huge swath of that is from the Diamond Princess. In terms of new cases, the fastest-growing one is South Korea. In fact, for the first time, there are more cases coming out of South Korea than there is coming out of China.
Also here we have our outcome of cases, and you can see that the death rates. As more and more of these undetermined cases go to the side of recovery, that death rate is falling. That is not a case fatality rate. We’re going to talk about that here in just the bits. Again, looking at the latest updates, one new case in Canada. This used to be a very small section here where you could look at multiple dates, and now things have just taken off in different places.
North America here on February 27th. A new case in Ontario. The husband of the previously confirmed case in Toronto. We’ve got Europe and the Middle East, and you can see here all of the different cases. 20 new cases in France. For instance, five new cases in Sweden. 40 new cases in Germany. Italy has now actually relaxed its testing criteria. Recent travelers to outbreak areas will not be tested anymore unless they show symptoms, and that may be because they may be low on testing; that’s just speculation. Not exactly sure if that is the case. We’ve got two new cases in the UK; 4 new cases in Switzerland. And Asia, the number of new cases in South Korea has actually top to China for the first time.
This is the article entitled Coronavirus Fatality Rates Vary Widely Depending on Age, Gender and Medical History – Some Patients Fare much Worse than Others. This is in a JAMA review article, where they actually looked at 72,000 covid-19 cases, and there was a dramatic shift. I will put the link to this article in the description. Let’s go right to the actual article: characteristics of an important lesson from the coronavirus disease 2019 outbreak in China.
This is 72,314 cases; pretty big numbers. Realizing of course, this doesn’t capture the entire picture, but it’s a good peek at what it is that’s going on. Let’s just jump to the Box findings. I like JAMA that they box these findings for you very concisely so out of 72,314 cases confirmed cases were 44,000; suspect the case is 16,000; diagnosed cases, 10,000; asymptomatic less than 1000.
Here’s the age distribution of actual infections in this study. And you can see the vast majority of infections occurred in people 30 to 79 years of age; that maybe because most of these people were out and about. But you can see here that as you get younger 10 to 19, less than 10, there was a reduced population. What about the spectrum of disease? Overall, 81% of these cases were mild, 14% were severe, and 5% were critical.
The thing that everyone’s looking for is the case fatality rate. So, overall, all of those cases had a case fatality rate of 2.3 percent. But how did that get distributed? You can see that one of the highest age-related case fatality rates was in people aged 80 years and over, and that was 14.8%. Well, if you’re in the decade before that, 70 -79, 8%. You can see that it came down dramatically.
What about those who were less than 9? If you were to go down into the body of the paper, there were no deaths of anybody 9 years of age or younger. And if you did have a critical case, your chances of making it were about 50%. So what about all those people that are 30 to 80 years of age? Well, if you actually calculate the numbers, you get approximately 1.2 percent case-fatality rates.
Let’s look at healthcare personnel that were infected. The 44,000 that were confirmed, 3.8% of them were healthcare personnel, and 63% of those were in Wuhan. In total, there are only five deaths in this group.
And they also tell you about how they determine which ones were mild, and which ones were severe., etc. Mild was determined as non-pneumonia or mild pneumonia. However, 14% were severe. What is severe? These are people that had shortness of breath; a respiratory frequency rate greater than 30 per minute; a blood oxygen saturation that was less than 93%, or partial pressure of oxygen fraction to the oxygen ratio of less than 300.
What is this less than 300 mean? It’s a determinant of how much oxygen they have to give you to keep your oxygen levels up. The more oxygen that they have to give you to keep your oxygen levels up, the lower this number goes, so you want to have a high number. This is called a p/f ratio. A lung infiltrates; that is more than 50 percent within 24 to 48 hours, and 5% were critical: respiratory failure; they are on ventilators; they are in septic shock; or they have multiple organ failure.
小于300是什么意思？这是决定他们必须给您多少氧气以保持体内氧气水平的决定因素。他们需要给您更多的氧气以保持体内的氧气水平，这个数字越低，因此您希望拥有一个更高的数字。这称为p / f比。肺部浸润；在24至48小时内超过50％，而5％则很严重：呼吸衰竭；他们在呼吸机上；他们正在败血性休克中；或他们有多个器官衰竭。
No deaths were reported among mild and severe cases. However, among critical cases, the case fatality rate was the flip of a coin. Those with pre-existing comorbid conditions, 10.5% for cardiovascular disease, 7.3% for diabetes, 6.3% for chronic respiratory disease, 6% for hypertension, 5.6 percent for cancer, and among the 44,000 cases, a total of 1,716 were healthcare workers, or about 3.8 percent. A lot of whom were in Wuhan.
Here is a key point: covid-19 rapidly spread from a single city to the entire country in just 30 days. The sheer speed of both the geographical expansion and the sudden increase in numbers of cases surprised and quickly overwhelmed health and public health services in China, particularly in Wuhan city and Hubei province.
Epidemic curves reflect what may be a mixed outbreak pattern, with early cases suggestive of a continuous common source, potentially zoonotic spillover at the Hunan Seafood Wholesale Market, and later cases suggestive of a propagated source as the virus began to be transmitted from person to person.
And here we have this graph. This is a great graph. We see going along here rather undetected, and then all of a sudden, we see this huge increase, depending on whether or not you’re looking at the date of onset of the cases or the date of diagnosis of the cases. In either situation, if we look at the date of onset, we can see here that things start to spread very, very quickly and overwhelm the health care delivery system.
No deaths were reported among mild and severe cases. I think that’s a pretty extraordinary statement, whether you believe the numbers or not, especially seeing based on this study. The majority of the cases were mild and severe, and 5% are critical, and half of those are dying.
So we can see by looking at this that the key is going to be early detection, and this brings up another interesting article here: Co-Diagnostic Stock Soars 57% on High Hopes for its Coronavirus Test. So if you looked at our last update, you would have seen that the current CDC kits are not performing like they should be. You may remember the case in San Diego; that was released early after they determined initially that the patient was negative; only to retest and find that the patient was in fact positive, and that could be because of a somewhat lower sensitivity of the test. Instead of it being 97%, it’s as low as is 70%.
Well, here is possibly a new test. That is developed by Co-Diagnostics. Its month-to-date gains to 333% after the company said it received CE Mark for its test, and this indicates that the test is compliant with health and safety standards, and now it is going to be allowed to be sold in the European economic area. There is an analyst that says that this test is easier to use than the test in use by the Centers for Disease Control and Prevention. Well, we’ll see what happens with this and hopefully, if it does work, it’ll be more available and faster than the current testing that we have.
Because of this article about the California issue that we have in Sacramento with the patient that was diagnosed as we talked about in our last update, some California health workers held in isolation, quarantine after exposure to coronavirus patient.
This is what we’ve been talking about, and that is if somebody comes into the hospital and has coronavirus, but we don’t know that, and we can’t detect that until they’re on the ventilator, and then we’re worried because they have a viral pneumonia, and none of our tests are positive then we get it tested and it’s positive.
We’re going to look back and see which health care workers were in contact with that patient. And then we’re going to have to quarantine them – dozens of health care workers in Solano County, California are under isolation, and some will be quarantined after being exposed to a patient who recently tested positive for the coronavirus.
Now we talked about this as it turns out this patient visited centers at two hospitals: North Bay, Vaca Valley Hospital in Vacaville, and the UC Davis Medical Center in Sacramento after the patient was transferred there.
现在，我们讨论了这个问题，结果证明该患者被转移到两家医院的中心：北湾，瓦卡维尔的Vaca Valley医院和萨克拉曼多的UC Davis医疗中心。
Now, we don’t know how many people have to be put on isolation and taken out of service basically, but they say it was under a hundred people. Now for them to say that high of a number, I’m thinking here that it’s not far under a hundred people, and it kind of goes to show that adjust the point where you need to have as many healthcare workers as possible to deal with this epidemic, you’re going to be knocking out a lot of healthcare workers if you can’t get the diagnosis right and quickly.
So the quote here by Dr. Matias, the county public health officer, said “at both hospitals, we are at present aggressively evaluating everyone who may have had contact with this patient. They are being identified, and their risk for exposure is being assessed.” “Efforts are made to identify all workers who may have been exposed.” a spokesman for North Bay Healthcare said, “and the number of healthcare workers impacted was a moving target.”
The announcement comes hours after county health officials declared a local emergency and activated its Department Operations Center to identify and screen those potentially exposed to the coronavirus. Officials called the virus a public health threat but caution that the risk to the public in Solano County remains low.
So that leads me to give you some advice on what to do, and we have to stop thinking about what am I going to do to protect myself and myself only, because what we need to do is we need to start and think like a group to protect ourselves from this virus, and what I mean by that is we need to take steps not only concentrating on how to prevent ourselves from getting the virus. You really need to think about this hard. If you get the virus, what are you going to do to prevent somebody else from getting the virus? If we all think this way, and we all act this way together, we can prevent a lot of problems. So we need to think together as a group and cooperate.
And so the number one thing I’m going to tell you here is get a thermometer. And the reason why I’m telling you that is so you can know objectively if you have a fever. The definition of a fever, by the way, is a temperature greater than 100.4 degrees Fahrenheit or 38.0 degrees centigrade, and I know some people will say well I’m always very cold, and therefore this is a temperature for me. I understand that, but I’m just letting you know that when you come to the hospital, and we check your temperature, these are the criteria that we’re going to use: a temperature of 100.4 or 38.0.
If you get a fever, I would say the second thing to do is don’t go to the hospital unless you need to, and what I mean by that is be reasonable, if it is only a cold, or if it is only mild flu symptoms, that you don’t need to go to the hospital for. If you have shortness of breath; if you have severe cough, things of that nature, those are the things that you need to go to the hospital for. Talk to your doctor, call into your nurse; do those sorts of things, because if you go, you’re going to inundate yourself into the hospital system, you’re going to be another patient that they have to see, and you’re going to expose yourself potentially to other people who might be infected.
Number three: don’t hoard masks. There are two types of masks. There are the regular surgical masks which we all know, and then there’s something called n-95 masks. Let me just tell you right now. A regular surgical mask, other than preventing you from touching something and then touching your nose, isn’t going to prevent you from getting coronavirus. If you’re breathing in air, then you’re breathing in the viruses in the air, and those surgical masks are not designed to filter air that you breathe in. Only the n95 masks do that, so wearing a surgical mask if you’re perfectly healthy, other than the fact of just trying to remind yourself not to touch your nose, your mouth is going to do you no good. So don’t take those masks. Those masks are needed for people at the hospital to put on patients who are already sick.
Now as far as n95 masks, those masks are needed by physicians and nurses and respiratory therapists and other ancillary service people at the hospital so that they can continue to treat people there and still be healthy and not have to be quarantined. It’s important that they get that equipment, because if they don’t have that equipment, they’re going to get sick, and they’re not going to be there at the hospital when you need them to be there.
Number four: if you are having severe symptoms, if you are having shortness of breath, you’re having dyspnea, chest pains, symptoms that are more severe, or you’re lethargic, that means sleepy, you’re not being responsive, these are all things that you should definitely go to the hospital for, and especially if you’re not getting better, but you should call ahead and find out where you should go because you don’t want to expose people at the hospital to your virus.
What they will do is they will probably put a mask on you, like a surgical mask, so that you don’t spread the virus to other healthcare workers. If you or your kids have symptoms, don’t see grandma and grandpa. We just went over what the mortality rates were for people above 70 years and 80 years of age. These are some very basic things that you can do to help prevent the spread of disease and to keep our hospitals healthy so that they can take care of you if you get sick.
We’re going to take a break, and we will come back on Monday morning. Thanks for joining us.