As part of the Virginia Lightning Round Tournament, we are soliciting question ideas from the community and will be highlighting the contributions of forecasters whose questions end up being asked. The goal of this tournament is to ask questions that might be useful toward improving the accuracy of COVID-19 models.

@RyanBeck got us started with the following suggestion, which is exactly the kind of thing we're looking for:

"forecasting the ratio of breakthrough cases and/or deaths might be useful, which VDH is tracking here. For cases and/or deaths I think the ratio of the 7 day moving average of breakthrough cases and/or deaths to the 7 day average of all cases and/or deaths at the desired end date would be a good metric and useful for understanding if vaccine efficacy is waning or not."