Could throwing some COVID19 vaccine doses in the trash actually help save lives? Buckle up. This thread might break your brain. 1/9

Some argue that it's a net positive for non-prioritized people (e.g. young people) to get leftover COVID19 vaccine doses that would otherwise end up in the trash. Let me try to convince you that this is far less helpful than you think and actually likely costs lives. 2/9

According to the CDC, someone aged 65-74 is 90 times more likely to die from COVID19 than someone 18-29. So vaccinating people 65-74 is *about 90 times more effective* at preventing death than vaccinating someone 18-29. 3/9

Even if a young person's 1st dose was saved from the trash, their *2nd* dose would likely have otherwise been used to vaccinate someone 65+. That dose is now only about one-ninetieth (1.1%) as effective, on avg, at saving lives since it's given to someone with a lower risk. 4/9

Counterintuitively, more lives would have been saved if that first dose had been put in the trash since it would have saved the second dose for a high-risk prioritized person. This holds while vaccine supply is limited. 5/9

Am I suggesting we should trash doses? Absolutely not! The point is that while supply is limited, sticking to the prioritization is important even for those "extra doses" *if our goal is to save the most lives*. A come-one-come-all strategy is simply not as effective. 6/9

There is effort involved in getting doses to high-risk people on the priority list. But it magnifies the positive impact of the dose by a factor of 3, 5, 10, or even 220 (by CDC calculations), depending on who gets it. With numbers like these, the effort is surely worth it. 7/9

The solution is to build a vaccination program that delivers doses to high priority groups quickly & efficiently without wasting doses. It will give us the biggest reductions in morbidity & mortality. And it will help speed the process for the rest of us when the time comes. 8/9

That said, if you have already gotten your 1st dose you should get your 2nd dose! This is what your doctor would surely recommend. The system is still being worked out, there is uncertainty and the pandemic has been hard on us all. Let's try to fix the system going forward. 9/9