Transcript for Latest updates on COVID-19: July 13, 2020
Here are some of the major developments we're tracking right now -- confirmed coronavirus cases around the globe closing in on 13 million. 3.3 million here at home, as more than 1 million Americans now recover. With me to start things off is ABC chief medical correspondent Dr. Jen Ashton, and Dr. Jen, unfortunately, we're seeing cases rise significantly around this country. But as we're watching this, we're also getting more information about the virus, how it spreads and our immunity and that was not necessarily great news to hear today. Right, and we have to take this with a chunk of salt. But you can talk about cases rising and people recovering without factoring in immunity. Here's what we know right now -- after infection with any virus, some mini-med school, the body produces an immune response, this is our antibody level. These igg antibodies are made based on Chinese published data, and there's more data coming in literally every week, these antibodies unfortunately seem to fade pretty quickly within as early as two, three months, this obviously has implications, clinically, societaly for reinfection for the durability of a vaccine and also for the ability for someone to be reinfected. So poem saying, I tested positive for antibodies, I'm good. Not so fast right now. Not so much, and we have seen a wide range in symptoms. It shows -- some of this published work shows a big difference in immunity based on how sick someone was. Exactly. This is a perfect example in medicine, even how the same disease is not one size fits all. Up to 50% people infected can show no symptoms. Recent data on this immune protection suggests that antibodies in people who had no symptoms reach lower levels and they fade more rapidly than people with more severe symptoms. If these antibody levels fade, obviously this concept of herd immunity could be difficult, if not impossible to achieve. Just a reminder, herd immunity requires anywhere 50%, 60%, 70% of the population to be permanently immuned. Naturally infected or a vaccination. That's in question. It doesn't look like anyone is permanently immuned. All right, research going on around this issue. What's left to learn? What we still need to figure out when you talk about long-term protection against covid-19, number one -- range in time. Does it last six months, 12 months? We need to understand better the differences between people who have been infected without symptoms and people who had symptoms on that spectrum of severity, we also need to remember it's not just antibodies that protect us, there are other immune factors like T cells at play. We need to understand that better. We definitely need to understand the differences between vaccine immunity versus natural infection and how they differ, they're not the same. A lot still left to learn. Dr. Jen, thank you very much. We'll turn now to ABC's Kyra Phillips in Washington with the latest headlines for us. Good afternoon, Kyra.
This transcript has been automatically generated and may not be 100% accurate.