中文全文 (Scroll down for English Transcript)
安东尼：非常感谢！我们的下一个问题是：目前对新冠病死率的估计是什么？由于有些无症状或只有轻微症状的人从未接受过新冠检测，我们是否高估了新冠病毒的致命性？此外，我听说一些患有例如心脏病等基础疾病的患者死时患有新冠，随之其死因被定为新冠，而不是其他基础疾病。这种计数法是否夸大了我们对死亡率的估计？
刘医生：老实说，没有人知道有究竟多少人真正受到新冠感染，因为不是所有人都接受新冠检测。获得实际数字的唯一方法就是，检测每一个人，无论他在那里或者有没有症状。有一些小型的研究项目在观察新冠的传染性，比如在德国或意大利的一些小镇中，研究院对小镇中的所有人都进行了新冠测试。这是唯一了解新冠在社区中传播程度的方法。当然，大家都知道我们不能用这些小镇的数据来推测整个世界，或者整个美国的情况。正因为我们并不知道真正的感染率，所以对此数值的估测的范围很大。
刘医生：同样，关于无症状人群到底占比多大，不同的数据给出的答案从20% 到 50-60%的都有。如果我们不测试每个人，那我们永远都不会知道真正的答案。最近纽约市的一项有趣的研究通过抗体研究显示，调查人群中有约 20% 患有新冠病毒。因此，如果纽约有 800 万人口，目前的新冠病例不到 20 万，那这个研究则显示患有新冠的人数超过当前确诊人数的40多倍。这个研究项目本身也存在一些问题，所以我们也不知道确切的感染率。很多人估计，美国的实际患病率有现在估算的10到20倍之多。
刘医生：病死率的估算也面临着同样的问题。如果不知道实际的感染率有多高，那我们也不会知道实际的病死率是多少。从我们现有的数据来看，新冠的致死率大约是 5%。如果测试的人数很多，例如像韩国那样，那么病死率会比较低——因为无症状或者症状轻微的患者也被算入分母中。在韩国，病死率有百分之二左右。但是，如果遇到意大利那样的情况，许多医院负荷运营，无法照料每位患者，那就是病死率更高的时候了。意大利的病死率现在接近 15%，这是我们不希望发生的情况。因为我们不希望医院负担过度。
刘医生：就如何判定新冠有关的死因而言，我们这边的做法是，如果你患有新冠，即使你同时患有其他潜在疾病，如慢性阻塞性肺病，或者由心脏问题、曾经有过心脏病发作的病史，基线健康水平低，新冠病毒的感染使你的病情更严重。即使在没有心脏病史的人中，新冠会导致心脏病发作。因为新冠使病情恶化，所以我们将其视为死因。但有些死亡不归因于新冠感染。比如，一个人得了肺炎随之去世，但他从未接受过新冠检测，其死因则仅为肺炎，不归因于新冠感染。因此，实际的新冠死亡数量应该更高。还有些人在家中去世，不算在内。关于实际死亡人数有很多问题，但我认为可能比现在所知的要高。
English Transcript
ANTHONY: Thank you very much. Our next question is: What are the current estimates for COVID mortality rates? Could it be that we’ve overestimated the deadliness of COVID since there are people with no to mild symptoms who were never tested? Additionally, I heard that some people with underlying conditions such as heart disease die with COVID-19, and then are counted as having passed away due to COVID, rather than these underlying conditions. Could this counting method inflate our estimation of mortality rate?
DR LIO: The honest answer to this is that nobody knows how many people are really infected. And that’s just because we’re not testing everyone. The only way to get the actual number is if we tested every single person regardless of what symptoms they had, where they are, and everyone gets tested. There have been some small studies looking at this. For example, they’ve taken a small town in Germany, or in Italy, and they’ve tested everyone in that town. That is the only way to get a sense of how much it’s spread in a community.
DR. LIO: Of course, you know we can’t extrapolate from that data to the entire world, or to the entire U.S. We don’t really know and because of that, there is a wide number of estimates as to how many people are infected. Again, there are different data on how many people are asymptomatic: anywhere from 20% of people to up to 50-60% of people asymptomatic. If we’re not testing everyone, we’ll never know the true answer.
DR. LIO: There was an interesting study recently that showed in New York City. From doing antibody studies, maybe around 20% of [study subjects] had COVID. If you have a population of 8 million in New York, and they have less than 200,000 cases, [the study result] is over 40 times the actual diagnosed rate. There are also problems with that study, and we don’t know the exact numbers.
DR. LIO: A lot of people are estimating that the actual number in the US might be 10 or might be 20 times higher than what we have right now. In terms of the fatality rate, that’s the same problem. If you don’t know what your true numbers (of cases) are you’ll never know what your actual fatality rate is. Right now from the numbers that we do see, that we have counted, the number is around 5%.
DR. LIO: If you’re testing more people, for example in South Korea, the fatality rate will be lower just because you’re testing people with milder symptoms or who have no symptoms. In Korea, [the fatality rate] is maybe around 2%. But, if you get into a situation like in Italy, where they have overwhelmed hospitals. They’re not able to take care of the patients that they have, and that is when you are going to have a higher fatality rate. Their number is closer to 15% right now. That is a situation we don’t want to have, because we don’t want to overwhelm our hospitals.
DR. LIO: In terms of how you count a death as related to COVID, the way we do it here is: if you have COVID, even if you have an underlying problem such as COPD (a lung disease) or heart problems, such as a previous heart attack that you’ve had, and you’re not healthy at baseline, COVID makes you sicker in general. COVID can cause heart attacks to come up even in people who don’t have a previous history of that. Because COVID makes it worse, we count it as a COVID death. There are also situations where deaths occur but are not attributed to COVID. Maybe someone has pneumonia, but they never got tested for COVID. Those deaths would be considered just pneumonia, and not attributed to COVID. So the death count should be higher. Some people die at home and are not counted. There are a lot of questions about what the actual death count is, but I think it might be higher than what it is.