Thread by @DrEricDing

So, I worry kids vaccine rollout might hit supply bottlenecks—➡️ latest info says it will not be possible to simply use existing adult Pfizer vaccine stock to draw up 1/3 adult dose, to use for kids. Kids shots will come in *new 10-dose vials*—to be still shipped out!🧵 #COVID19

2) The reason we cannot just cut the adult dose is that doing so would result in an injection volume of 0.1mL, which is considered too small for intramuscular injection. Instead, there will be a new diluted formulation of the vaccine for use in age 5-11—0.2mL doses with 10 mcg

3) Initial doses will be allocated to the states, which will then direct them to individual practices and perhaps other locations. Doctors offices and pharmacies will be able to request doses, but are not guaranteed to receive the number they request.

4) The FDA’s advisory panel is scheduled to discuss pediatric 5-11 vaccines on October 26th, followed by the CDC’s ACIP advisory panel November 2nd and 3rd. Approval hopefully by CDC director on Nov 3rd or 4th.

5) Some states are meantime hoping to “pre-position” doses at injection sites as early as November 1st so vaccination can begin as quickly as possible. But this will depend heavily on supply chain logistics in delivering the new pediatric 10-dose Pfizer vaccine vials 🧪 in time!

6) My question is — why can’t we just draw 1/3 and the dilute the adult Pfizer 30 mcg vaccine doses… divide by 3 to get 10 mcg, then dilute the 0.1mL for greater volume to 0.2 mL??? Seriously, I want to know. I’m going to ask a Pfizer colleague why.