Antibodies, Case Fatality, Clinical Recommendations, 2nd Infections (Lecture 21)
Welcome to another MedCram lecture. We will talk about the coronavirus update, and we see here are 7,500 total confirmed cases based on the data from the WHO and CDC. Coming out of China, total deaths over 2000; total recovered 14, 772. If we look at the WorldOmeter, as it’s correctly pronounced, we can see here there are active and inactive cases. Closed cases 16,814, 88% of those have been recovered or discharged, and 12 percent deaths in the closed cases so far. Of course, these numbers are underreported.
Most of those cases were mild cases, however. If we break those cases down again into the difference between what’s going on in China and what’s going on outside of China, we can get another picture. You can see here the trend is that every day there seems to be more and more new cases. Well, inside of China, the number of cases is actually diminishing, as we can see here overall. If we go up to total deaths, over 2,000 deaths total.
I want to talk a little bit about what’s going on in terms of what the labs are doing to fight coronavirus, the covid-19 disease, specifically nice interview here on NPR regarding antibodies. First one to talk a little bit about antibodies, and how they’re made. So you have these B cells, and they each have different receptors on these B cells. These B cells are made to do one thing really; that is to make antibodies. And these receptors on the cells are there to receive any type of antigen that you might come in contact with. An antigen could be a protein of a virus or a protein of a bacteria, etc. etc.
What is really quite amazing is that you have so many different types of receptors on millions and millions of B cells that just about any kind of foreign protein that gets introduced into your body will make a b-cell against that. And so here we can see that each B cell has a different antigen receptor, and the antigen receptors of only one B cell will combine with that antigen.
So if you have a virus; that virus is going to stimulate its particular b-cell, and it will activate, and it will get help from T-cells, cytokines. And it will cause the cell to divide and rapidly enlarge into a huge clonal representation of that b-cell. So you have thousands, millions of these B cells, and all these B cells do is they produce antibodies, and these antibodies go out and attack cells that have the virus in it or the virus itself. And finally when the infection is done, then these B cells just kind of go away, but there’s always a certain amount of a population of these B cells ready to strike again if that virus comes again, and this is typically how it works with a particular virus.
So if you get a vaccine against the virus, like polio, if you get a vaccine against the virus, like the Hepatitis B virus, that vaccine goes through the same way. Here, you get an antigen stimulating a b-cell. Of course, when we give a vaccine in some of the cases, we give a vaccine that has just the protein without the virus, so you don’t get the actual disease, and that causes your B cells to make a lot of these antibodies in preparation for if you ever were to be infected with that virus, you’ll be ready to make an immune response.
Of course, sometimes what happens is the virus may mutate, and so the proteins are different enough that the antibodies that you have against those proteins may not be as effective. This is kind of what happens with colds. You might get multiple colds in a year, and it’s possibly because, well, it could be a different virus of rhinovirus versus a regular coronavirus, or it could be a rhinovirus that’s mutated enough so that the former immunization that you got against the virus is no longer effective because it’s mutated.
Well, going back to this interview. What they’re looking at is drugs that will prevent the virus from replicating, but there’s an interesting company that they’re looking at called ABcellera, which they identify antibodies from patients who have already recovered from infection because they’re finely-tuned immune systems have already figured out a way to clear the virus. So what they can do is they can look through millions of different immune cells and find the one that is right for coronavirus.
In fact, what they’ve done, and this is kind of amazing as they’ve taken mice, and instead of making mouse antibodies, these mice are actually using human immune system cells to make not mouse antibodies, but to actually make fully human antibodies, and that’s just amazing. So, of course, the next step is to inject these coronaviruses into these mice and start getting these antibodies out, and actually seeing whether or not they work. Testing them in trials and then seeing whether or not this antibody against the coronavirus, specifically the one that makes the covid-19 disease, otherwise known as SARS-COV2, is going to be effective.
So this is one of the treatments that’s on the horizon, and the reason why this is really important for us to get, as we see here in this USA Today article, looking again at that data from China that we talked about yesterday. They’re looking at statistics here, and they’re saying that the coronavirus is 20 times more lethal than the flu based on the case fatality rate as the death toll as we talked about passes 2000.
We can see here that based on the calculations that they were doing, the global death toll from the virus was listed at 2009 as of Tuesday evening, and that the total infections rose to more than 75,000. If you do the calculation, the overall death rate for the virus was 2.3 percent. However, the season’s flu death in the United States was at about 0.1%, making this, of course, a more deadly than the regular flu, but not as deadly as the SARS outbreak back in 2002, which was at around 10%.
Fortunately, we have to talk about another physician who’s died in China, Dr. Liu. He was the director of a Chinese hospital at the epicenter of the coronavirus outbreak and was one of the neurosurgeons as well.
So these B cells, and how they become plasma cells, and how they secrete immunoglobulins, or antibodies. It is all very specific and distinct, including how viruses infect the human cells. This is something that I would like to go into a little more detail.
There have been a lot of questions about immunity, and what happens after someone recovers, and we’ve seen some examples here the United States of people who have recovered, specifically the gentleman in Washington, but there have been some questions, some rumors, and some claims that people can get the virus twice, and that, for instance, people can have a lot worse reaction the second time around, and that there may not be immunity.
I haven’t seen any reports of that, and so it’s very difficult to come up with an answer to that question. I think it might be a little early in the course to see if that is in fact happening. One thing. I will make a point, however, is that often times when someone gets a viral infection, their ability to withstand secondary bacterial infections is reduced, and so it’s not uncommon to have secondary bacterial infections when someone has a severe viral infection.
And so I want to end this update with an excellent article that was published on the 12th of February 2020 on the practical recommendations for critical care and anesthesia teams caring for novel coronavirus patients, and I will put a link in the description below.
This article that is written in Canada talks about their experience with the SARS virus back in 2002. And it talks about very practical things to do. For instance, in the Intensive Care Unit, what kind of personal protective equipment to be wearing; how the flow of air in these rooms; whether or not they’re negative or positive pressure rooms are very important.
For instance, if you are doing, generally speaking, an operation that’s in an operating room, and that room is run under positive pressure ventilation, something that, of course, you would never want to have happened if you’re doing an operation on somebody with this kind of virus. And so they talk about switching those kind of patients into negative pressure rooms to do the operation so that you don’t infect other people in the hospital. And so I think it’s an excellent read for physicians, health care providers, who are going to be taking care of these coronavirus or covid-19 patients.
It also talks about when to use n95 masks versus these powered air-purifying respirators, otherwise known as peppers, and who should be wearing them, and talking about, for instance, hot zones, warm zones, and cold zones. Hot zones being in the patient’s room, specifically where there’s negative pressure ventilation; warm zones when you’re outside the patient’s room but still in the Intensive Care Unit; and then finally cold zones when you’re outside of the intensive care unit. So I think this is really important information. And again, we will put a link to it in the description below. Thanks for joining us!