COVID Vaccinations are Coming, What Does it Mean for my Self-Funded Health Plan?

With the impending authorization from the FDA for emergency use of the COVID vaccines from the manufacturers Pfizer and Moderna, one question that will be facing self-funded health plans is, “What is this going to end up costing me?”
Most likely, plans are going to cover the cost of these treatments at 100%, and we’d expect that anywhere from 60-100% of a plan’s population over the age of 18 will be receiving this treatment in the calendar year 2021. It’s very rare for such a large portion of a plan’s population to receive the same treatment in the course of a year, so the costs to the plan are likely to be more than nominal, but to what extent?
There is no official news from the PBMs or manufacturers as to how much these treatments will cost, but we can use prices negotiated by the US Government as a guidepost to give us an idea of where the prices may end up.
https://www.cnbc.com/2020/11/17/covid-vaccines-how-much-they-cost-whos-bought-them-and-how-theyre-stored.html
Sources indicate that the Pfizer vaccine was negotiated at $20 per dose by the US government, so a two dose treatment would run $40 per patient. The Moderna price is likely to be closer to $30-$35 per dose, meaning a two dose treatment would be $60-$70 per patient.
Additionally, the administration of a vaccine typically comes with a professional administrative fee for the provider who is performing the vaccination. The AP Book of Business averages about $25 ($50 for two injections) across the PPO networks for that fee. 
When we add these up, the range for a vaccination seems to end up in the $70-$120 range per patient. Given all of the unknowns, it would be prudent to be conservative in our estimations, so when discussing the financial liability associated with vaccinations, we would suggest a baseline assumption of $100 per adult plan member. 
At this point, this is purely a projection and we will hope to gain more clarity in the coming days and weeks. However, plans that wish to budget for this expense should be able to use this projection as a strong baseline until new information becomes available.

*Updates as of 12/16:
Since the publishing of this original post, we have confirmed that since the US Government has already purchased 100M doses of the Pfizer vaccine and 200M doses of the Moderna vaccine, the costs of those vaccines will not be incurred by plans. This means that up to 150M Americans may be able to receive a COVID vaccine without their insurance incurring the costs of the drugs (the administration of the vaccine will still carry the costs noted above).
Once the 300M doses of vaccine purchased by the government are distributed and administered it is unclear as to whether or not plans would have to bear the cost burden of any additional vaccine requirements.