Suppose 50% of vaccinated people would attend this event, and so would 50% of unvaccinated people, after considering the risks (ergo, there is no risk compensation). However, only vaccinated people are allowed to go to the event. Then the vaccinated people could have increased rates of Covid compared to unvaccinated people because of being more likely to attend superspreader events, even though they did not increase their level of risk compared to the unvaccinated population.
Whether this is the actual reason for the apparent negative effectiveness would depend on the actual percentages, and how common/dangerous superspreader events really are.
A vaccination requirement could result in lower apparent effectiveness; so could risk compensation. In order to determine how much risk compensation occurred, we have to determine how much the vaccination requirement lowered the effectiveness. Without that analysis, concluding that risk compensation has a big enough effect to cause or contribute significantly to negative effectiveness is premature.
I am otherwise unsure of what you are trying to get at. The unvaccinated were prevented from doing a risky activity, and the vaccinated were allowed to do the activity (with a lower risk due to their status), yes.
Well, if this is consistently applied across many events, the unvaccinated will not be allowed risky activities and the vaccinated will be allowed risky activities. Which means in practice consistently higher number of risky activities available for the vaccinated. I agree that this effect might not be significantly big and more measurements would be needed.
This is true to an extent. Unvaccinated people are still able to attend. They just would need to forge their vaccination card. I think this is not particularly hard to do, though it’s not trivially easy and many unvaccinated people would not do it for ethical reasons.
Suppose 50% of vaccinated people would attend this event, and so would 50% of unvaccinated people, after considering the risks (ergo, there is no risk compensation). However, only vaccinated people are allowed to go to the event. Then the vaccinated people could have increased rates of Covid compared to unvaccinated people because of being more likely to attend superspreader events, even though they did not increase their level of risk compared to the unvaccinated population.
Whether this is the actual reason for the apparent negative effectiveness would depend on the actual percentages, and how common/dangerous superspreader events really are.
But effectively, the unvaccinated were not allowed to have the same level of risk as vaccinated if they couldn’t come to the event, right?
A vaccination requirement could result in lower apparent effectiveness; so could risk compensation. In order to determine how much risk compensation occurred, we have to determine how much the vaccination requirement lowered the effectiveness. Without that analysis, concluding that risk compensation has a big enough effect to cause or contribute significantly to negative effectiveness is premature.
I am otherwise unsure of what you are trying to get at. The unvaccinated were prevented from doing a risky activity, and the vaccinated were allowed to do the activity (with a lower risk due to their status), yes.
Well, if this is consistently applied across many events, the unvaccinated will not be allowed risky activities and the vaccinated will be allowed risky activities. Which means in practice consistently higher number of risky activities available for the vaccinated. I agree that this effect might not be significantly big and more measurements would be needed.
This is true to an extent. Unvaccinated people are still able to attend. They just would need to forge their vaccination card. I think this is not particularly hard to do, though it’s not trivially easy and many unvaccinated people would not do it for ethical reasons.