infrastructure or lack frof in countries like rwanda and lie beer d liberia. you need infrastructure when it comes to the pfizer vaccines. it s a two dose regimen. you need special syringes. is the infrastructure there to support it? yes, so we ve known for a long time the requirements for some of the vaccines. and the countries have been aware of those requirements and are taking great strides to provide some of the infrastructure including the ultra cold temperature freezers and working on the distribution networks. so it s really less so about the capacity to manage the doses but it s more about getting the doses available to those countries. steph, so as this is all happening, you got a cdc advisory committee in an hour into a two-day meeting on booster shots. explain what they re considering