[MUSIC] Welcome to testing, contact tracing and cohort ing. We have a brief disclosure and more move right into testing strategies. We have three learning objectives for this section of the course. The first is to review the testing platforms and the pros and cons of each of those platforms. We'll talk about testing strategies in both an outbreak in a non outbreak setting. And then we'll go on to discuss how to prioritize individuals to test when capacity is low, moving into the types of tests. There are three kinds of tests. The first two are diagnostic tests, and these look for the presence of the virus in our bodies. These air used to diagnose an active infection. The most common type is apply. Marie's chain reaction, which we also know as PCR, and the other is a more recently FDA emergency use authorization approved antigen based testing strategy. And we'll go into both of these on greater detailed. The third type of test is an antibody tests, and these identify antibodies to the virus, usually in our blood. These tests determine if someone has previously had a covert 19 infection antibodies air made by your immune system to fight off viruses or bacteria, and we can identify antibiotics. There are specific to SARS cov to in your blood. Remember, no tests are perfect. This means that sometimes, despite our best efforts, the results from the cove in 19 test or any test could be wrong. Let's talk in more detail about PCR based testing. This is usually done to test somebody with signs and symptoms of an infection. PCR based tests work by detecting RNA, which is the genetic material of the virus, the swabs taken from the back of the nose or the nasal pharynx. And this could be pretty uncomfortable, especially for older adults. So this is best done with a health care worker who was wearing personal protective equipment, including an N 95 mask and a face shield. Getting a swab from the nose affairs can often make people sneeze or cough, which generates aerosols. A positive PCR test means that there is a viral RNA in that person's nasal fair ings, and therefore it's in the respiratory tract. A positive PCR test should not be used. Decide when someone is no longer able to spread the virus. We know that PCR based test can continue to detect viral RNA for days to weeks after an individual is no longer shutting the viral particles that spread Cove in 19. So for this reason, a PCR based test should not be used aside. Was among come out of transmission based precautions. The pros to using the PCR based test is that this is accurate, reliable, insensitive. It's similar to influenza testing the cons. As I said before, it's pretty uncomfortable. Not all people with an infection will have RNA in their samples. So these air false negatives and then people can remain positive for weeks, yet are no longer capable of infecting others. This is often to send out Testa's well, which means that it can sometimes have a long turnaround time. Let's move on to antigen based testing. These are also diagnostic test that look for active infection, and this test is usually done to people who have signs and symptoms of an active covered 19 infection. The antigen tests look for markers on the outer surface of the virus, and the swaps here could be taken from the front of the nose, which is much easier to do and also to be the recipient of that test and the indigent based test can be run on machines that are being distributed, turned nursing homes and assisted living facilities. And some of these tests we'll talk about in a few more slides don't even need a machine to be run the pros to the antigen based testing or that they have a rapid turnaround time, and the samples are easy to collect. The cons. It's a lower sensitivity tests, meaning there could be false negatives. It's also lower specificity, meaning that there are false positives. And this can have some pretty significant impacts on what happens to our residents and assisted living as well as to our staff members. It creates a lot of anxiety when there's a false positive test, and it also requires staff to run these tests. So rather than being sent out, it means that our administrators, for the assistance of in communities need to designate staff that have the time and the training to do the energon based testing. The third type of tests are antibody tests. These look for previous infection and should never be used to diagnose someone for whom there is a concern for active infection. The most common type of anti by this objective is called I G. When someone gets infected with the new virus or bacteria, our body starts to make antibodies within the few days. The first one that develops is called I G M. These disappear in 2 to 4 weeks after an initial infection. The other main type of antibody that develops is called big. These could be found in blood, usually 10 to 14 days after an infection, and these persist for weeks to months. Positive I G antibody tests means that the person was previously infected with the virus these air best used for public health surveillance. So the pros are the advantages for an antibody. Tests is it could be performed after someone recovers or people who had never had symptoms of a covert 19 infection. It could mean that there is some protection from future stars Kobe to infections. But this is still a developing area, so we really don't know about this for sure. Yet cons or disadvantages to the antibody tests, as I do not tell you when you were infected and interpreting the test depends a lot on how Maney Covad, 19 infections were in the area. This is part of what we really want, these tests to be reserved and used by public health officials.
