COVID-19: Testing Confusion, Reopening Strategies, and More
Dr. Steven Bishop returned to Facebook Live on Wednesday, May 13, to provide another weekly update on COVID-19.
He began by discussing testing and the general confusion that has come about recently regarding testing and reliability.
He broke it down by test:
- PCR tests: This is the nasal swab test. It checks for the presence of the virus. It is not extremely sensitive, which means you could have a negative test and still have the virus. It seems to be about a coin flip.
So, if the test is negative, you not should feel overly confident that that means you don't have the infection. If you test positive though, that is very accurate. That is a safe bet that you have the virus.
- Antibody tests: These tests are testing for three types of antibodies: IgA, IgM, and IgG. IgA and IgM antibodies reveal if you are acutely sick. If you test positive, you likely have acquired the virus recently and are probably actively sick with it.
The third one, IgG, is one that may not turn positive until you have completely recovered, and it may take up to a month after you get well to show a positive test.
So, what is happening is that people are sick and receive an IgG test that comes back negative. That is not an appropriate use of that test. It should not be used during the first few days of illness.
Now, if you get an IgA or IgM test during the first few days of illness, then you can be more confident in the results because that test is much better. False positives, from a public health concern, are less dangerous, because it will requires extra caution to be taken, even though you may not actually have the virus. Better safe than sorry, so to speak.
- Antigen test: This is a new test. It looks for pieces of the virus. It is a swab test that is used to test for active infection, similar to the PCR tests. The jury is out on the accuracy of these tests.
Then, he answered questions from the audience. Because of technical difficulties, there are two videos. Read the Q&A recap below and watch both videos for more.
When libraries open up, will borrowing books be problematic? It appears that libraries will have a fairly rigorous decontamination process for their books.
In addition, because the virus likely doesn't live on a book surface for more than 2-3 days, they probably will try to clean the hard surface of the books and then hold them for several days before renting them out again. This will give any virus left on the surface time to die.
Be sure to ask your local library before taking out any books to be sure.
How adequate or inadequate is the national capacity for PCR testing? We're waiting to see. Some medical providers can get enough, and some cannot, . That includes PCR tests and antibody tests. Antibody tests seem to be more available. We are hoping to see the supply increase across the board shortly.
When will the reliable saliva swab test be available? The saliva swab test is available. However, we are using them less than the nasal swab, simply to limit the amount of PPE used.
Patients can generally do the nasal swab test on their own, requiring less PPE, while the saliva swab test, because it essentially involves gagging yourself, is best done by a doctor, which requires more PPE.
What is the current thinking on ibuprofen? A lot of the early data that came out around ibuprofen, Advil, Aleve, etc., hasn't really been borne out in subsequent studies. I wouldn't worry so much about using ibuprofen.
However, if you can use Tylenol instead, that's an easy switch to make. But if ibuprofen is what you have and what works, I wouldn't shy away from it. It's important to note that most of these only matter if you are actively sick. If you are feeling fine, your normal pain reliever such as Advil should continue to work.
As long as stylists are cleaning, and we are wearing masks, do you feel it is OK to venture out for hair cuts? Yes, as long as you take into account your own risk factors. If you are older and have lots of medical problems, it might be a good idea to continue to wait.
What is your take on what appears to be downward trends in hospitalizations and deaths in Georgia and Florida? I hope it's good, and I hope we have that trend here in Virginia and other places. However, time will tell. Once we reopen, we can't tell what effect that has had until 2-4 weeks after that occurs.
I'm having work done inside the house. Any advice? If you have to have work done inside the house, whatever company you're using, I would make sure they are following safety procedures.
They need to wear a mask, be there for the minimum time necessary, wash their hands when they come in, etc. Don't shake their hands. Minimize your contact with them and stay six feet away. After they leave, wipe down any surface they touch.
What do we know at this point about a positive antibody test result? If you have a positive IgG test at any point, you can be quite confident you either have or have had the virus at some point.
If you have an IgA or IgM antibody, you probably have the virus at the moment.
However, there are some false positives associated with IgA or IgM tests, meaning you could get a positive test back but you don't actually have the virus. In general, if you have a positive antibody test, I would consider that to be fairly accurate.
Is there reliable data on how the virus spread through the air and how long it lives when outside, whether that's on a beach, sitting in a park, etc.? I haven't seen updated data on this recently, but the information remains the same.
It travels through air droplets (coughing, sneezing, breathing heavily), but doesn't travel very far, which is why social distancing recommends staying 6-10 feet away. So if you're outside and sitting on a beach or in a park, keeping your distance is a good strategy, and wearing a mask only helps.
Do you think information about people recovering is important or is it more important to know about infection and death rates? For the most part, if people aren't dying, you can consider them to be recovered within a few weeks. That being said, recovery can mean many things. There are many people who have "recovered" from the virus who are pretty ill because of the damage that came from the virus.
That's true of any virus, such as bacterial pneumonia, which can take weeks or months to fully recover. So recovery is a sort of loose team, because it's difficult to quantify. That's why infection and mortality rates are important and probably more reliable indicators.
Which of the metrics do you think is the most important to follow to try to understand the current infection rate in a state or county? There are various opinions on this, but I personally think the infection rate as represented by antibody testing is probably the most accurate thing to follow, especially in terms of figuring out who has been infected (the IgG testing).
I think that gives us the best information with regard to who, in total, has actually had the infection, which will tell us whether we are trending toward herd immunity, whether the infection is spreading well beyond what we originally thought, etc.
That being said, the PCRs and the other antibodies (IgA and IgM) are very important in figuring out who is acutely sick, because as we reopen, we need to identify the newly infected people.
Do you recommend investing in a pulse oximeter? No, I don't think that's necessary, unless you have an underlying lung problem or something of that nature that would require you to check your oxygen level on a regular basis.
Should I take my six-month-old in for a well visit right now for vaccines, or wait? Yes. If they have a separate area for well visits, and they are following cleaning protocols.
What is the rate of accuracy of the IgG antibody test? It is very accurate. It is very close to 100%. If you have IgG antibodies, you can be certain that you either have or have had the virus in the past.
Part One (27:02)
Part Two (3:16)