Earlier this month, the World Health Organization announced it was tracking a new COVID-19 “variant of interest,” XBB.1.16, which has spread to more than 30 countries, including the U.S. The variant, which is also known as Arcturus, genetically resembles the Omicron strain which drove a surge of infections and hospitalizations in Oregon that peaked in late January last year. According to a forecast prepared by Peter Graven, the lead data scientist at Oregon Health & Science University, the Arcturus variant and another variant, XBB.1.9, will drive a wave of new hospitalizations in Oregon that will peak at around 500 patients in late June. Still, Graven expects the state’s hospital system to be able to handle any surge fueled by Arcturus which appears to be associated with relatively mild cases of infection. Peter Graven joins us to talk about the outlook for COVID and other respiratory illnesses such as RSV and the flu.
Note: The following transcript was created by a computer and edited by a volunteer.
Dave Miller: This is Think Out Loud on OPB. I’m Dave Miller. Earlier this month, the World Health Organization announced it was tracking a new COVID-19 variant of interest. It is popularly being called Arcturus and it’s now spread to more than 30 countries including the US. Peter Graven is the director of the Office of Advanced Analytics at Oregon Health Sciences University (OHSU). He joins us now in person for the first time to talk about this new variant and the outlook more broadly for COVID in Oregon going forward. It’s great to have you in the studio.
Peter Graven: It’s great to be back indoors even though it’s very nice outdoors today.
Miller: Yeah, we should do the show outdoors. If there is a single number that people like you have been paying the most attention to over the course of the pandemic, it is COVID hospitalizations or people who have tested positive for COVID and are hospitalized, so two similar overlapping things are not exactly the same thing. What does that number look like right now?
Graven: Well, right now we’re at actually very low rates. There are 161 patients across the whole state that qualify for that, meaning they’ve tested positive for COVID in their hospital. We do know that a good portion of those are actually there for other reasons. As COVID is spreading, it’s quite prevalent and so if you come in for something else, we’re going to probably find it and you’ll still test positive, you’ll be recorded as a COVID patient. But we do still have those other patients that are there for COVID. It looks traditional in the sense of affecting the breathing can be very difficult.
Miller: But the majority of people say who came for a tonsillectomy or anything and they may not even know that they had COVID?
Graven: Right. And so when we think about the data, that number 161 is important, but the one I care about more is how much it impacts the operations of the hospital. And that’s going to be a smaller number where we’re going to be kind of really focused on the ones that are taking up beds that won’t be there for other reasons. We do know COVID is complicated and it affects the body in many ways. So it’s not like a clean slate on these other patients, they affect them in certain ways, but I’m more interested in whether it affects our ability to deliver care to Oregonians.
Miller: So 161 right now throughout the state. Just to put that in perspective, the high point in COVID hospitalizations in Oregon was during the Delta surge in September of 2021. That was close to 1,200 people. So an eight or ninefold difference there. What does it tell you that the number of COVID hospitalizations has not gone up in recent months despite mask mandates being lifted in healthcare settings and despite the fact that at this point very few people, more broadly in public settings, are masking?
Graven: The reality is it’s a very transmissible virus and if anything, it’s become more transmissible, but fewer people have it and that’s due to immunity. So many people have had it. In fact, the model that I have would show on average, the average person’s had it twice. And when you combine how many times people have had it with some immunity you get from vaccines, it turns out that the virus is running into problems finding people. In fact, now it’s going to stay, it’s going to keep finding people, but we’re not at the same stage of a wave right now as we have been previously.
Miller: We’ll talk about the wave to come that’s expected in just a second, but I want to go back to your model. When you plug in all these numbers to work on projections, embedded in that is the idea that every Oregonian on average has been infected twice?
Graven: Yes. And it’s hard to believe. And you might not have been tested each time. It could have been a different cold or sometimes it could have been an ex an infection that you didn’t even know the symptoms of. But based on what we’ve seen about how the virus moves, that is my estimate and in terms of how often we think people have had it. There are going to be some who probably maybe never had it, but because it’s so common, we do think that people have built up a fair bit of immunity to it. And the good news is that means that when you’ve had it before, either by vaccine or infection, we know your rate of hospitalization goes way down, probably 10 times less. So that’s the thing that, of course, affects me at OHSU.
Miller: And that is on top of people who’ve gotten two shots or one or more boosters on top of that. Right?
Graven: Right. So, the boosters, of course, are providing some temporary basis of not getting infected at all, usually three or four months where you feel pretty good like you’re not going to get infected. And then that begins to wane but the underlying protection against hospitalization is lasting. And it gets re-upped with the boosters, it gets re-upped with an infection and that can last for quite a while.
Miller: So, let’s turn to this new variant. How much do we know about those of us who don’t like to use letters and numbers to talk about variants of what we are calling Arcturus?
Graven: Yeah, I think the big thing is it’s not too different from the variant that’s here currently. So XBB.1.5 is the one that’s here now.
Miller: Is that not Omicron?
Graven: It is a form of Omicron. That’s right. And so we’re getting into the details of these and the new version only really has one or two mutations different from that. But they’re critical ones that are causing it to have some more immune escape, meaning some of the people who had protection before their body isn’t going to recognize this one and they’ll go ahead and get infected again.
And so that’s what we’re dealing with. In fact, that’s what we’ve been dealing with many times with these variants. The new one finds a little crease, something that it can get past some existing immunity. It doesn’t mean the entire population is now susceptible, but there’s going to be some percentage of the people who’ve had it are now susceptible again.
Miller: So there’s the chance of evading the versions of immunity that people have. And there’s also the question of if it does evade immunity, how virulent it is, how likely is it to make people moderately sick or very sick? What do we know about that?
Graven: We’re not seeing any increases from the existing strains. That’s always great news and that’s something we look for carefully because that’s what drove Delta. Not only was it more transmissible, but it was much more severe, almost double the rate of hospitalization for the same kind of person. And with this one, we’re not seeing any indication of increased severity. And so that’s a positive sign and likely will mean that any hospitalizations, most of them will be for other causes.
Miller: So then how big a wave are you expecting in Oregon? And what is the time frame?
Graven: The most recent forecast that came out two weeks ago, I’m showing a wave that is gonna peak here at the end of June and is expected to reach 505, that’s the number that we have on June 27th. Now, I will say that’s a bit speculative where I’m typing in parameters about what I think is the variant, what it’s done in India and other places and seeing what that would mean in Oregon. Getting the timing of a wave like that is tricky. But we do think that there’s going to be some increase from this new variant. And while that’s a higher hospitalization number–not to the 1,200 or so that we mentioned before–it is higher than what we’ve had recently. Again, I think many of those are most likely to be for other reasons.
Miller: So there will be a potential crest of the wave in June. It’s just one more reminder - and Delta was sort of a summer wave as well. Is there any clear seasonality? We’re in the fourth year right now. Are there patterns that have emerged that can let someone like you say, with this virus, it’s going to be in this month or these months going forward?
Graven: There really isn’t clear data on that. I would say with pretty good certainty, you can expect a winter wave of some sort.
Miller: To coincide with RSV and the flu?
Graven: Exactly. I would guess most years we’re gonna see COVID go up during those years. But what you can’t say is that it’s going to go away all summer or the rest of the season. And we’ve seen waves at just about every month of the year. Because of that, we don’t have a clear seasonal pattern on that. That’s largely because it’s still mutating so much that we haven’t really seen a very steady state in terms of its pattern around the globe.
Miller: Can we expect that or is it possible that it’ll always be this erratic, fast changing virus?
Graven: It’s a little outside my expertise there. My guess is that it does settle down a little bit as some of these key variants become known and it finds more of a traditional pattern of people’s immunity waning mild changes to it causing reinfection.
Miller: In January, the Food and Drug Administration proposed a system like annual flu shots for COVID boosters, but other authorities since then, including advisors to the World Health Organization, they’ve recommended against annual shots for low risk groups. So where does this leave us when? What do you see as a potential future of COVID boosters or recommendations for when big numbers of people in the population should get them?
Graven: Yeah, I think the key here is it is changing and we do need to keep listening. We’re not in a spot where we can predict it like the flu in terms of when you should get it, what it should look like. There could be a new variant that shows up in three months that really does mean we all need to get a booster or we could learn more about the long term impacts of exposures. So I think the key right now is indeed to keep listening and seeing what is recommended and follow those recommendations. I think to your point earlier, we really haven’t seen a clear seasonal pattern yet either. So part of it is when would you get that booster? I think that part is still trying to be understood.
Miller: Then there’s also the question of how good we will be, or virus makers will be, at actually guessing right in terms of the variant that’s likely to be spreading three to six months or whatever the time frame is from when they make that year’s version of the shot. Will they be as effective at targeting the variant of concern as flu vaccines are?
Graven: I think the vaccine makers are really looking to take whatever is most current, and it has been a game changer with how vaccines are made today compared to the old versions of the flu vaccines. They’re able to take a clear genetic picture of what’s circulating and really design the vaccine around that. That’s not been the case before, but there is still a time frame between getting that made, getting it out to the population. So you can expect we’re always gonna be a little behind. And if the new current variant is quite a bit different than that, then indeed, there may be things that we need to do in the short term to prevent infection or to wait for an update.
Certainly, if it’s more severe as we’ve discussed, the short term strategies of masking and avoiding others indoors, may come back for that. But again, though, I always think of those as short term strategies to get you to the next thing and hopefully the vaccines will be that.
Miller: Peter Graven, thanks very much.
Graven: Thank you, Dave.
Miller: Peter Graven is the lead data scientist at OHSU.
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