Roman Jaeschke: And what do we know about the severity of BA.5 [infection]?
Dominik Mertz: To the best of my knowledge, similar to the other Omicrons, it looks from those countries that already went through the BA.5 wave that in general they saw even fewer hospitalizations than they would have expected. But that is probably not because of BA.5 being milder than the previous Omicrons. It’s just because there’s more immunity in the population than half a year ago, so probably similar. I think that’s the bottom line, in my mind.
Roman Jaeschke: Could it also be that we have some outpatient treatment these days that may prevent some admissions—critical care admissions—and deaths? Again, different places will have different rules, but how do we deal with outpatient treatment of vulnerable people with COVID-19 in Ontario?
Dominik Mertz: As you mentioned, it’s different from jurisdiction to jurisdiction. In the Ontario setting pretty much everyone who can prescribe can prescribe Paxlovid, and it’s available in the local pharmacies, and the pharmacists make also sure that in terms of interactions, which are the main challenge with Paxlovid, it is safe to use or whether any of the other medications need to be changed. So, that’s the process. Then we have different recommended criteria from the province, which are a little bit more lenient than the Science Table recommendations, which are a little bit more strict. There you would go by age, vaccine status, and number of comorbidities and based on that you need to have an indication for Paxlovid or not. All of this being said, the data behind all of that are very indirect and we don’t really understand very well at this point how much Paxlovid adds in a vaccinated individual. Highest risk, unvaccinated—no question. We do have the data, which show very high efficacy of this treatment in preventing severe infection, in preventing death. We don’t have the same data for lower-risk individuals or standard-risk individuals that include many of us who are vaccinated, may have one or the other comorbidity. So we don’t really know how much it adds in those situations, which makes it often sort of a judgment call what you do. But I think at this point, following those criteria based on the risk profile, based on this Science Table [data], an estimate of a ≥5% risk of hospital admissions would result in an indication for Paxlovid. It’s probably a reasonable approach: sort of accepting that uncertainty that we have, but at the same time erring on the side of caution of probably overprescribing at this point.
Roman Jaeschke: What are the downsides of Paxlovid? Without knowing I could think of side effects, I could think about cost, I could think about drug interactions. What are they? Why are we hesitant to give it, say, as a prevention or in the mildest disease but not highest risk?
Dominik Mertz: The hesitancy stems from the fact that you haven’t a proven effect in that population, right? So that’s one piece. And when we think about low-risk individuals, we don’t have any data that would support that benefit to start with. The main challenge or drawback, if you think about using it more leniently at this point, is mostly the interactions, which can be challenging. Again, you can argue that in a young, healthy individual you could easily prescribe Paxlovid because they are usually not on other drugs, but those are the ones that, to the best of our knowledge, don’t benefit from the treatment. And in the elderly population with comorbidities, where you have more likely or likely more significant effect, that’s where you have all those other medications in the system. And that’s usually the main challenge. From a side-effect perspective, it’s a well-tolerated drug, so that’s less of an issue.
Roman Jaeschke: Thank you very much for this update as of today, as of the beginning of July [2022]. We’ll see how the situation evolves. I hope we will not have to talk in a week or two because it would mean some dramatic changes, but I’m already inviting you for an update, say, in another month. Thank you very much, Professor Mertz, I really appreciate it and I appreciate your work on probably 20 chapters in the McMaster Textbook of Internal Medicine. You are one of our star authors. Thank you.
Dominik Mertz: Thank you, Roman.
Roman Jaeschke: Goodbye.
Dominik Mertz: Okay, thanks. Bye-bye.
