Bloomberg:

I'm from Bloomberg News. Thank you for taking your time to speak to us today. I'm sure you're all very busy. I have three questions. My first question is: What are the underlying conditions that really influence whether a patient survives or doesn't survive this disease? Dr. Cao mentioned various comorbidities, but are these the main factors you look for when you look at some patients who do and don't survive? My second question is: Now that you're saying that the outbreak in Wuhan and Hubei more generally are sort of petering out towards an end, what do you expect the case fatality rate to be across the whole province? I think in Wuhan, initially it was it was much higher than the rest of China. Do you expect the case fatality rate and Hubei to come down towards the rate in the rest of China? My third question goes back to the first question from Reuters: Do you expect to be able to trace the patient zero, where this disease cross from animals into humans? And is your expectation that will be linked to the seafood market that Dr. Du just mentioned? Thank you. 

Cao Wei:

I'll take the first question. As I just mentioned, there are some risk factors already identified for COVID-19 patients, including the elderly people, comorbidities, etc. And these are the risk factors you could identify before you go to the hospital, once you have been diagnosed. 

And there are also very important signals showing that you are transferring or you are processing from a mild type of case, or common type of case, to the severely or critically ill patients, which include the change or continuous decreasing of lymphocytes, which is the indication that your immune system is gradually being broken down. And also the elevation, or robust elevation of inflammatory markers, which is also another sign that the immune systems are activating. And also if there is progressing changes of the lung radiology, including the infiltrations of bilateral lungs. This is another important sign you should pay attention to, which indicates you might be going to the critically ill patients. 

Du Bin:

For the risk factors for mortality in patients with COVID-19, I do believe we are still waiting for more evidence coming from the investigations. Because previously during discussion with my colleagues, all of us believe that the hypertension is a risk factor for either the severe cases or the mortality rates. However, we also know that hypertension is associated with older age. 

So currently we have no idea, which is the confounding factor. Because these two risk factors—older age and the hypertension, diabetes as well—are closely correlated with each other. So we're still waiting for more evidence. However, according to current data, I agree with Dr. Cao that the lymphocytopenia is one of the signals, and probably the cardiac injury biomarkers is another signal for mortality. 

And the second question concerns the case fatality rate. I am sorry that I don't think this is the right time to calculate or estimate the case fatality rate. Even though, right now, the majority of the patients have been discharged back home, but we are still having more than 3,000 or 4,000 patients in the hospital. We still have no idea how many of them will survive, and how many of them will die. A certain number of them will die. Absolutely. So it's not the right time to estimate the case fatality rate at present. In my mind, the case fatality rate is a retrospective term rather than the terminology we can discuss right now. And we also know that the supportive, life-sustaining treatment employed in the intensive care unit may prolong the patient's life, which will make some early deaths into late deaths. That's one of the reasons for the later increase in the case fatality rate, as you can see. 

And the reason for a higher case fatality rate in Wuhan than in other provinces—that I just can't remember if I have already answered the same question in the last press conference or not, but anyway—in my mind that the reason number one is that there is always a learning curve. Our colleagues—the healthcare workers in other provinces—they learn from our experience, and they learn from our failures, so they can treat their patients better than us. And the second reason: They have much fewer cases than what we have here in Wuhan, in Hubei, which means that patient there had a better chance for better medical care. They have enough resources; they have enough human beings, enough health care workers around them; they have enough ventilators, monitors, and all the other devices. I don't think the difference can be explained by any genome mutation at the present time. But if this is the case, I'm not surprised. 

The last question concerns the number zero patient. I'm sorry, I'm not the right one to answer the question, because I think this is the task for the CDC staff. They should look for who is the index case for this whole outbreak. But currently, I have no idea what is going on there. Sorry for that. Thanks. 

Xi Yanchun:

OK. Next question, please. The middle area, the lady in the fourth line with long hair.