WEBVTT - Immunity to Coronavirus: Why It's so Complicated 0:00:00.120 --> 0:00:03.680 It's Monday, June one. I'm Oscar Ramirez from the Daily 0:00:03.720 --> 0:00:06.600 Dive podcast in Los Angeles, and this is your daily 0:00:06.600 --> 0:00:11.560 coronavirus update. Will unrest continues across the country. Concerns about 0:00:11.560 --> 0:00:14.960 the coronavirus pandemics still remain. We are still waiting for 0:00:14.960 --> 0:00:18.040 a treatment or vaccine, but there's also some uncertainty to 0:00:18.120 --> 0:00:20.680 immunity for those that have had the disease and recovered. 0:00:21.160 --> 0:00:23.360 We still don't know for how long someone might be 0:00:23.400 --> 0:00:26.400 protected from COVID nineteen after they have gotten it and 0:00:26.480 --> 0:00:29.120 in your body. It's not just anybodies that are fighting 0:00:29.120 --> 0:00:32.440 the virus. B cells and T cells also helped fight 0:00:32.479 --> 0:00:37.519 illnesses after anybody's have disappeared. Katherine Wu, science reporter at 0:00:37.520 --> 0:00:41.200 Smithsonian Magazine, joins us for why immunity that the coronavirus 0:00:41.280 --> 0:00:44.640 is so complicated. Thanks for joining us, Katherine, Thank you 0:00:44.720 --> 0:00:47.320 for inviting me. It's great to be here. I wanted 0:00:47.320 --> 0:00:51.440 to talk about the coronavirus COVID nineteen. We've been battling 0:00:51.479 --> 0:00:54.640 this for some months now, and one of the things 0:00:54.720 --> 0:00:56.560 that we haven't had a chance to really wrap our 0:00:56.600 --> 0:01:01.040 head around is immunity from the virus. Once you get it, 0:01:01.200 --> 0:01:04.080 Are you even completely immune from it? And there's a 0:01:04.080 --> 0:01:06.800 lot of stuff that goes into it. It's pretty complicated 0:01:07.160 --> 0:01:09.639 in the way it works in our bodies. So Catherine 0:01:09.640 --> 0:01:12.959 helped us out a little bit to understand why immunity 0:01:13.000 --> 0:01:16.080 to this has been so complicated so far. Yeah, I mean, 0:01:16.120 --> 0:01:18.440 I'm really glad that you're looking into this, because it's 0:01:18.480 --> 0:01:21.600 best a complicated question, and I think during such a 0:01:21.680 --> 0:01:25.680 chaotic time when there are lives at stakes, people really 0:01:25.680 --> 0:01:28.959 want clear cut answers, and I as the report that 0:01:29.040 --> 0:01:31.200 we don't have a lot of those right now. I 0:01:31.240 --> 0:01:34.480 think the most important takeaway at this point is that 0:01:34.520 --> 0:01:37.839 even though we have tests and a lot of people 0:01:37.880 --> 0:01:40.920 working very hard on this disease and how to fight it, 0:01:41.480 --> 0:01:45.120 we don't really have clear cut answers on whether or 0:01:45.160 --> 0:01:48.640 not people are going to be protected from getting infective 0:01:48.720 --> 0:01:51.560 with the virus a second time, even if they've recovered 0:01:51.640 --> 0:01:54.240 from about a public night scene. The way that I 0:01:54.360 --> 0:01:56.400 sort of look at this is a lot of people 0:01:56.440 --> 0:01:59.200 by now have heard of antibody tests, either of the 0:01:59.240 --> 0:02:02.560 tests that searching your blood for those immune molecules that 0:02:02.680 --> 0:02:05.800 your body makes in response to a pathogen that's trying 0:02:05.880 --> 0:02:09.720 to infect you kind of like dusting for fingerprints after 0:02:10.040 --> 0:02:12.720 a crime has occurred at a crime scene. It's evidence 0:02:12.840 --> 0:02:15.840 that something has been in your body. But that's a 0:02:15.960 --> 0:02:19.639 very past focused book at the disease. It doesn't tell 0:02:19.680 --> 0:02:22.639 you a whole lot about the speaker. Yeah, And one 0:02:22.639 --> 0:02:24.800 of the things, whether anybody's, that I didn't really know 0:02:24.840 --> 0:02:26.520 about too much, is that they have a kind of 0:02:26.520 --> 0:02:29.919 a short lifespan, and they disappear from your blood after 0:02:29.960 --> 0:02:32.359 a few weeks or months, depending on how strong your 0:02:32.400 --> 0:02:36.000 immune system response was. And it's really these other cells 0:02:36.080 --> 0:02:40.040 in your body that kind of remember what those antibodies were. 0:02:40.120 --> 0:02:42.840 So if the same pathogen comes back into your body 0:02:42.840 --> 0:02:45.480 obviously we're talking about COVID nineteen, if you get infected 0:02:45.480 --> 0:02:48.120 again or something, these other cells are the ones that 0:02:48.280 --> 0:02:51.880 remanufacture those antibodies. So there's a lot of other stuff 0:02:51.919 --> 0:02:58.120 involved in really making your body continue to fight these diseases. Yeah, exactly, 0:02:58.400 --> 0:03:01.480 that's a really pretty point, So I thinks drive home 0:03:01.560 --> 0:03:05.160 so specifically about the antibodies, You're exactly right. Those are 0:03:05.200 --> 0:03:09.800 molecules made by the body by a population called B cells, 0:03:09.840 --> 0:03:12.200 And it's sort of the difference between you know that 0:03:12.280 --> 0:03:15.600 old addage like you know, give them person a fish 0:03:15.600 --> 0:03:17.480 and they eat for a day, keeps them how to 0:03:17.520 --> 0:03:20.480 fish and they can eat for life. Those antibodies are 0:03:20.560 --> 0:03:24.560 pretty temporary, but what is really important are those B cells, 0:03:24.600 --> 0:03:28.760 which remember how to make those antibodies against the virus itself. 0:03:29.160 --> 0:03:31.320 And so what you really want is those B cells 0:03:31.400 --> 0:03:33.720 to stick out around some then will kind of go 0:03:33.880 --> 0:03:36.400 dormant after you've recovered from an infesttion and then their 0:03:36.440 --> 0:03:39.280 ideal circumstances so hang around in your body. So then 0:03:39.280 --> 0:03:41.840 we'll keep dividing or just hang out for a really 0:03:41.840 --> 0:03:43.720 long time in the bone marrow. And then if that 0:03:43.840 --> 0:03:47.160 pathogen kind of comes to invade your body again, they 0:03:47.200 --> 0:03:50.600 will recognize that the pathogen hast come back and manifest 0:03:50.880 --> 0:03:53.720 those antibodies for a second time, and the response will 0:03:53.760 --> 0:03:57.280 be even stronger and faster than before, possibly so fast 0:03:57.280 --> 0:03:59.480 and so strong that you may not even experience symptoms 0:03:59.560 --> 0:04:02.880 the second time. Yeah, And of course that's what everybody 0:04:03.160 --> 0:04:06.000 would hope for that they can have. So there's also 0:04:06.560 --> 0:04:09.680 there's B cells, and then there's T cells T as 0:04:09.720 --> 0:04:12.920 in TOM, and some of these cells also help in 0:04:13.000 --> 0:04:16.920 this same thing, manufacturing and helping fight the viruses once 0:04:16.960 --> 0:04:20.320 they come back. So B cells and T cells are 0:04:20.520 --> 0:04:23.880 kind of two prongs of what's called the adaptive I 0:04:23.920 --> 0:04:27.440 mean response, and that's the kind of slow wave that 0:04:27.600 --> 0:04:31.080 kicks in roughly a week into infection, depending on what 0:04:31.200 --> 0:04:34.480 pathogen we're really talking about. And T cells serve kind 0:04:34.480 --> 0:04:36.919 of a different function, Like I guess I see B 0:04:37.040 --> 0:04:41.400 cells as weapons factories they're making antibodies, whereas T cells 0:04:41.400 --> 0:04:44.560 can actually accomplish a lot on their own. T cells 0:04:44.560 --> 0:04:48.360 can either help B cells make antibodies, so they're sort 0:04:48.400 --> 0:04:52.240 of supporting the antibody factories as they're churning these really 0:04:52.279 --> 0:04:55.760 important disease fighting molecules out, or T cells can sort 0:04:55.760 --> 0:04:59.320 of fight their own war. They can actually identify your 0:04:59.320 --> 0:05:02.000 own cells like the rest of the cells in your body, 0:05:02.080 --> 0:05:04.640 like the cells that might line your airway, recognize the 0:05:04.680 --> 0:05:07.520 ones that have been infested with a virus, and actually 0:05:07.560 --> 0:05:10.560 send the signals to tell them to self destruct, because 0:05:10.720 --> 0:05:13.120 at that point they figure that sells the lost cause 0:05:13.200 --> 0:05:15.839 it's been effect of the pathogen. The best way to 0:05:15.920 --> 0:05:18.520 deal with the situation is to make that cell get 0:05:18.600 --> 0:05:21.599 rid of itself, and that will also theoretically destroy the 0:05:21.680 --> 0:05:25.240 viruses inside of it. Do we have any information yet 0:05:25.440 --> 0:05:28.159 I know we're very uncertain on this whole thing. I 0:05:28.160 --> 0:05:31.440 had been reading about study in South Korea that basically 0:05:31.480 --> 0:05:35.800 said some people that have retested positive again for coronavirus 0:05:36.360 --> 0:05:40.520 weren't shedding active particles of the virus. In other words, 0:05:40.839 --> 0:05:43.159 they were clearing all those people. If you had COVID 0:05:43.640 --> 0:05:47.039 nineteen and you recovered, you were no longer infectious to 0:05:47.160 --> 0:05:50.880 other people. So it kind of plays into this whole thing. 0:05:50.880 --> 0:05:52.920 But has there been any other studies going around. That's 0:05:52.920 --> 0:05:55.440 the only one that I've seen. Really, I'm glad you 0:05:55.520 --> 0:05:57.720 brought up that bit of news because I think they 0:05:57.720 --> 0:05:59.320 have a little bit of nuance there that's may be 0:05:59.440 --> 0:06:02.120 important to get into. I feel like there were a 0:06:02.160 --> 0:06:06.000 few reports coming out in early days talking about reinfection, 0:06:06.120 --> 0:06:10.599 like people were testing positive, having symptoms, then recovering and 0:06:10.720 --> 0:06:13.240 testing negative. And in this case, I'm talking about the 0:06:13.279 --> 0:06:15.960 test that looks for the virus, not antibody. So this 0:06:16.080 --> 0:06:18.839 is a diagnostic test that can tell whether or not 0:06:18.920 --> 0:06:22.960 the viruses in your body, and probably active people were 0:06:23.000 --> 0:06:26.160 testing positive, than negative, then positive again, and people were 0:06:26.160 --> 0:06:28.800 wondering are people getting reinfected? Does that mean that these 0:06:28.800 --> 0:06:30.800 people aren't And the into the virus, and we're just 0:06:30.880 --> 0:06:33.400 doomed to get infected over and over again. I think 0:06:33.440 --> 0:06:36.040 a lot of experts have since come forward to say 0:06:36.120 --> 0:06:39.600 that these people probably we're fighting the virus. The virus 0:06:39.760 --> 0:06:43.760 sort of declined to very low, difficult to detect levels 0:06:43.800 --> 0:06:46.359 in their body, and the tests were missing the virus 0:06:46.400 --> 0:06:49.040 because it was so scarce in the body. And then 0:06:49.080 --> 0:06:51.839 after some time, maybe the immune system kind of relaxed 0:06:51.920 --> 0:06:54.200 and the virus maybe took the opportunity to sort of 0:06:54.200 --> 0:06:57.440 surge back to higher levels levels that were maybe triggering 0:06:57.440 --> 0:07:00.240 another bout of symptoms or making the virus detectable by 0:07:00.240 --> 0:07:03.720 these tests again. And so I think in that sense, 0:07:04.160 --> 0:07:06.640 it's really difficult to say exactly what was going on 0:07:06.920 --> 0:07:11.440 inside the body. But you know, that doesn't necessarily bad news. 0:07:11.600 --> 0:07:15.960 There are a lot of pathogens, including viruses, bacteria, parasites 0:07:15.960 --> 0:07:18.240 that can kind of linger in the body. But if 0:07:18.280 --> 0:07:21.480 we're able to detect this early, this won't necessarily be 0:07:21.560 --> 0:07:24.400 universal for everyone, and we can develop treatments that can 0:07:24.440 --> 0:07:27.480 either keep the virus at extremely low levels so that 0:07:27.520 --> 0:07:30.800 people aren't experiencing symptoms or are shedding the virus. That's 0:07:30.880 --> 0:07:33.880 kind of what happens with HIV and people can you know, 0:07:33.960 --> 0:07:37.120 live very long, healthy lives in that case, or you know, 0:07:37.160 --> 0:07:39.440 this will kind of inform when can we sort of 0:07:39.480 --> 0:07:42.720 target and treat the virus so that it doesn't establish 0:07:42.840 --> 0:07:45.040 maybe a population in the body that's going to be 0:07:45.200 --> 0:07:48.040 this long lasting. But I definitely don't want to give 0:07:48.080 --> 0:07:50.640 people the impression that this is the norm or that 0:07:50.680 --> 0:07:53.240 they're going to be stuck with this virus permanently, just 0:07:53.320 --> 0:07:56.160 that that could be the case for a subpopulation of people. 0:07:56.680 --> 0:07:59.520 There's still so much yet to be learned about the 0:07:59.600 --> 0:08:01.960 virus and how it lives within the body and all, 0:08:02.200 --> 0:08:05.040 and it's important for vaccine development and all that, so 0:08:05.400 --> 0:08:08.200 hopefully soon we can start understanding a little bit more. 0:08:08.800 --> 0:08:12.400 Catherine Wu, science reporter at Smithsonian Magazine, thank you very 0:08:12.440 --> 0:08:17.680 much for joining us. Thank you my Oscar Emiraz, and 0:08:17.680 --> 0:08:20.840 this has been your daily coronavirus update. Don't forget that. 0:08:20.920 --> 0:08:22.840 For today's big news stories, you can check me out 0:08:22.840 --> 0:08:25.560 on the Daily Dive podcast every Monday through Friday, So 0:08:25.640 --> 0:08:27.920 follow us on I Heart Radio or wherever you get 0:08:27.920 --> 0:08:28.560 your podcast.