Thanks for the excellent analysis, as always! Here's a question for you: my husband has been skeptical of the safety of these two vaccines because they are, we think anyway, mRNA vaccines. We understand this to be an entirely new kind of vaccine. He's concerned that the safety profile may be less well understood than others. I'd love to learn whether this is a valid concern or not. Thanks!
You're correct that these are both mRNA vaccines, yes. And you're right to have a certain amount of reservations regarding the potential safety issues of a new vaccine technology. However, I don't think that there are huge reasons to be concerned about these on the basis of their being mRNA-based. mRNA is one of the most abundant things in a human cell, and we know rather a lot about it and how it is made. While this doesn't guarantee that there won't be unforeseen safety issues related to the mRNA-based mechanism, I would put the risk of that at a low level.
Instead, when worrying about safety, I would look more to the fact that this vaccine generates an immune response to antigens from an ill-characterized virus. The immune response to the virus spike protein might have other impacts. What if there is a natural human protein that has some similarity to the virus spike? Is it possible that people will have cross-reactive antibodies that will cause some kind of autoimmune reaction? This is not so far-fetched, though generally such things are rare. Still, we see these long-term reactions to COVID-19 that I would suspect have an autoimmune component, and we need to be watchful that the vaccine won't be able to generate that type of response. I would also put this at a low level of risk overall, but it's the main thing that I'm looking for in any safety data that might be released.
The thing is, that won't be unique to an mRNA virus. If that happens, it would be because of the virus antigens used, and vaccine designs would need to be revised to avoid whatever signal is causing the safety event. Thankfully, we don't have any evidence of such a safety outcome. Let's cross that bridge if any only if we come to it.
Anyhow, thank you for reading and I'm glad the newsletter is proving useful!
Thanks for the excellent analysis, as always! Here's a question for you: my husband has been skeptical of the safety of these two vaccines because they are, we think anyway, mRNA vaccines. We understand this to be an entirely new kind of vaccine. He's concerned that the safety profile may be less well understood than others. I'd love to learn whether this is a valid concern or not. Thanks!
You're correct that these are both mRNA vaccines, yes. And you're right to have a certain amount of reservations regarding the potential safety issues of a new vaccine technology. However, I don't think that there are huge reasons to be concerned about these on the basis of their being mRNA-based. mRNA is one of the most abundant things in a human cell, and we know rather a lot about it and how it is made. While this doesn't guarantee that there won't be unforeseen safety issues related to the mRNA-based mechanism, I would put the risk of that at a low level.
Instead, when worrying about safety, I would look more to the fact that this vaccine generates an immune response to antigens from an ill-characterized virus. The immune response to the virus spike protein might have other impacts. What if there is a natural human protein that has some similarity to the virus spike? Is it possible that people will have cross-reactive antibodies that will cause some kind of autoimmune reaction? This is not so far-fetched, though generally such things are rare. Still, we see these long-term reactions to COVID-19 that I would suspect have an autoimmune component, and we need to be watchful that the vaccine won't be able to generate that type of response. I would also put this at a low level of risk overall, but it's the main thing that I'm looking for in any safety data that might be released.
The thing is, that won't be unique to an mRNA virus. If that happens, it would be because of the virus antigens used, and vaccine designs would need to be revised to avoid whatever signal is causing the safety event. Thankfully, we don't have any evidence of such a safety outcome. Let's cross that bridge if any only if we come to it.
Anyhow, thank you for reading and I'm glad the newsletter is proving useful!