Apr 15 / WHO /
source
“Helen Braswell: (
40:22)
I was hoping maybe Maria or Mike could give us some information about serology testing. I know that a number of countries have been starting to do this work. Is there any picture yet of how good the serology tests are, how reliable they are, and what is being seen in the testing that has been done to date?
So, hi Helen. Yeah, I will start with this and perhaps Mike would like to add. So yes, we are working with a number of countries across the globe on looking at the use of serologic testing for COVID-19. So as you know there are a large number of rapid tests that are available now commercially to purchase and we’re working with FIND and we’re working with labs that have experienced with coronaviruses to look at validation of those with well-characterized Sera. It’s important for us to be able to evaluate how these actually work with clinical samples. So, that is a process that is ongoing.
There are a number of countries right now that are conducting serologic studies, which are looking either at stored samples that were collected throughout this pandemic for other clinical reasons, blood bank, blood donations, or are doing these studies prospectively. Today we had a teleconference with 160 groups, 160 people, who are working with us on our early investigations, which we’re calling the unity studies now. These are early epidemiologic investigations that focus on cases and contacts, that focus on healthcare workers, that’s a separate protocol, a separate protocol for household transmission, and a fourth protocol looking at age, population based sera surveys.
We had a call with them today to see where they are. We have more than 40 countries who are utilizing these core protocols in their own countries, and we’re starting to see some results from some of them from the molecular testing, not yet from the serology. And they’re asking us what are the tests that we can use. So we’re working very hard to validate those tests so that we can be able to say here are four or five serologic assays that could be used so that we can have a better readout on how they actually work.
In addition to that, we have another serologic solidarity study. It’s called the solidarity two study, which is working to estimate global sera prevalence and the first thing that this study is doing, it’s called solidarity two. It’s working on pulling together a serum panel, a standardized serum panel, across the globe so that they could standardize assays and that they can use one protocol to estimate global sera prevalence. That is a process that is ongoing and we’re hoping that we will get some results from that in the coming months.
Having said that, there are some serologic studies that we’re now starting to see being published. Unfortunately, I haven’t seen full papers of these using full methodology. I’ve seen a study from Denmark, I’ve seen a study from Germany suggesting around at 3.5 to 14% sera prevalence. We need to really understand the methods that were used, the assays that were used in terms of their sensitivity and specificity before we can have a good understanding of what this actually means. But of course these numbers are lower, the sera prevalence in these two studies which is not representative globally are lower than I think what many people were expecting. Certainly lower than what some of the models had predicted.
But we’re working with our partners to understand what all of this means in terms of our understanding of the epidemic waves that may happen with this pandemic virus.
Mike?
Dr. Michael J. Ryan: (
43:59)
And just to add Helen, and Maria is there really speaking where sera epidemiologic studies, where the testing is done and validated labs as well. Where the testing is benched on in labs. There is a whole other world of rapid diagnostic test or point of care diagnostics and people are talking very much about can we do the diagnosis at the bedside, either a PCR based or there are new diagnostic tests based on antigen detection. And what they do is they detect the proteins of the virus in the sample. Or rapid diagnostic test based on the antibody that’s developed by the body in response to the virus. And there’s a lot of very important innovation going on in that space, but there are real…
We need to be very, very careful antigen tests the sensitivity of those tests can be low. In other words, they may pick up anything from 30 to 80% of true infections. In other words, you can have people who get a negative test who actually have had the infection. The same with some of the antibody tests.
The important consideration with antibody tests is that many people take up to two weeks or more to develop the antibodies in response to having the infection, so they could actually turn out to be negative on the antibody test but actually have had the infection.
Now, none of those are barriers to introducing these products as part of a comprehensive strategy, but we do need to be careful to ensure that introducing rapid test is done as part of a comprehensive diagnostic strategy, a comprehensive testing strategy, and where governments can have validated tests that they introduce into the system in a way that adds to the control of the virus, that adds to surveillance, that adds to diagnosis and doesn’t cause unnecessary confusion. And many governments around the world are doing that just now.”
oops forgot my mask
