If people who are protected against one subvariant are also well-protected against others, why would there ever be a surge in a place that already had an Omicron surge (like Europe)? Is it just changes in behavior/regulations combined with immunity fading from vaccines & boosters, and nothing to do with the difference between subvariants at all?
Good question. I cannot give you a precise answer, but I do think it is related to overall immunity and the size of the susceptible population. European countries have, generally, had better control of the pandemic than American communities, which means they may still have a larger percentage of people who have not had experience with the virus. Alternatively, this could be an effect of waning of vaccine-mediated immunity and boosters, but in the US, vaccine uptake and booster uptake is so much worse than in Europe.
What I feel confident saying is that clearly Europe has a BA.2-susceptible population and the virus is spreading through it. The US so far does not appear to have as large a susceptible population. While I've speculated as to why, the answer is that I don't really know much beyond what we can see in the data.
I think we have reached a level of experience with this virus where we are realizing the limitations of what we've learned about it so far. I am afraid that we are probably going to understand the difference between the US and Europe in this particular moment *after* that information is at its most useful.
In my last piece I tried to provide some general principles that offer a way to think about your local and personal situation as best as we currently can--evaluate the number of susceptible people that may be around you against your personal vulnerability, and calibrate your protective measures to that. For now this is the best we can do.
If people who are protected against one subvariant are also well-protected against others, why would there ever be a surge in a place that already had an Omicron surge (like Europe)? Is it just changes in behavior/regulations combined with immunity fading from vaccines & boosters, and nothing to do with the difference between subvariants at all?
Good question. I cannot give you a precise answer, but I do think it is related to overall immunity and the size of the susceptible population. European countries have, generally, had better control of the pandemic than American communities, which means they may still have a larger percentage of people who have not had experience with the virus. Alternatively, this could be an effect of waning of vaccine-mediated immunity and boosters, but in the US, vaccine uptake and booster uptake is so much worse than in Europe.
What I feel confident saying is that clearly Europe has a BA.2-susceptible population and the virus is spreading through it. The US so far does not appear to have as large a susceptible population. While I've speculated as to why, the answer is that I don't really know much beyond what we can see in the data.
I think we have reached a level of experience with this virus where we are realizing the limitations of what we've learned about it so far. I am afraid that we are probably going to understand the difference between the US and Europe in this particular moment *after* that information is at its most useful.
In my last piece I tried to provide some general principles that offer a way to think about your local and personal situation as best as we currently can--evaluate the number of susceptible people that may be around you against your personal vulnerability, and calibrate your protective measures to that. For now this is the best we can do.