Briefing Chat: Is DNA repair the secret to a long life? Whales and mole-rats offer tantalizing hints

**Nick Howe** (0:04)
Hello, and welcome to The Briefing Chat Show, the Friday show where we talk about a couple of stories that have been highlighted in The Nature Briefing. Well, actually, The Nature Briefing itself is on holiday this week, but we are still here, rest assured, listeners, we have stories for you. And joining me this week is Sharmini Bundell to tell me about hers. What have you got for us this time, Sharmini?

**Shamini Bundell** (0:25)
So, I've had to skip the briefing and go straight to nature.com, where I've found a cool new story about Long COVID, which is interesting and mysterious and causing a lot of problems for a lot of people. People who have COVID-19, have an infection, get ill, and then certain symptoms carry on for months and months and months, and can be really debilitating.
And this study is looking at the link between Long COVID and dormant viruses that live secretly inside us, that you might have in your body right now, but not even know about it.

**Nick Howe** (1:03)
It sounds ominous. Yeah.

**Shamini Bundell** (1:06)
Well, it's usually not. I think that's the sort of point here is that usually they're dormant. So obviously, we've all had lots of infections with viruses in our life, particularly in childhood, you get loads and loads of infections. And if you are currently healthy, probably those infections have been defeated by your immune system. But sometimes, some of these pathogens are never fully cleared. They're actually sort of lurking inside you, but kept in check by your healthy immune system. And that's partly also why in terms of certain conditions where your immune system is weakened, like an HIV infection, for example, it's often these dormant viruses resurfacing that cause a lot of other problems.
So there was this idea, maybe, is there some link here with COVID-19, with long COVID?

**Nick Howe** (1:57)
Yeah, yeah, I guess if you have an infection, a bad one, like COVID, and then that weakens your immune system, then things could reemerge. It makes sense.

**Shamini Bundell** (2:05)
Yeah, that sort of raises a question for me, which I don't know the answer to, of whether that happens with other infections, in fact, and it's not something that we're aware of. But this particular study that was out in Nature this week looked into the link between COVID-19 specifically, cases of people who were hospitalized in 2020 and 2021 And they've gone back and got a load of samples of blood and nasal swabs and lung fluids and looked for these common viruses to see if they were in fact reactivated. And what they found is that nearly half of those people had a reactivation of common viruses in their body.
And they then tracked those same people for a year afterwards and found that the people who had reactivated viruses later had increased bodily inflammation, elevated immune cell activity, and more cellular damage, which they don't think they specifically looked at long COVID diagnoses, which long COVID is hard to define at this point. But there definitely seems to be a difference in the kind of long-term impact on your body if you did have this reawakened virus.

**Nick Howe** (3:21)
And that could potentially then lead to the fatigue and other symptoms that people with long COVID have reported. Is that the thinking?

**Shamini Bundell** (3:28)
Well, so there is a lot that we don't know. This is just a link. This is just correlation.
So, for example, they don't know exactly why these viruses are reawakening in the first place. And one researcher quoted in the piece says it's probably that the COVID-19 is inducing the stress that then triggers the reactivations and then the reactivations then further amplify the inflammation that's been caused by the COVID-19, so it's all kind of circular in that way. So they don't exactly know how that's working. And then they don't know whether the COVID-19 is causing the viruses to reawaken and then viruses are causing the long COVID symptoms, or if the virus is reawakening are just another symptom of the immune system being exhausted and all of the problems. It's just another problem being caused by the SARS-CoV-2 infection and then that kind of illness. So yeah, cause and effect not figured out yet.

**Nick Howe** (4:28)
No. Well, what do they hope then they can use this study for? Could they give people antivirals or something when they get COVID to try and ward this off or something like that?

**Shamini Bundell** (4:39)
Yeah, exactly. So apparently they've got a phase two clinical trial launched right now. And that's exactly the point, because they have looked at these reawakened viruses, various things, Epstein-Barr viruses, herpes virus, some viruses which are usually totally harmless that just are in our body, but don't cause any symptoms. So they're sort of seeing what they are. And then this particular trial is testing antivirals that are targeting herpes viruses. But the idea is that, and we don't know yet, but if these reactivating viruses are causing their own problems inherently, then maybe instead of treating COVID-19 by targeting SARS-CoV-2, maybe we should be treating COVID-19 with antivirals for other things.