Per CDC about 5 million doses of vaccine have been shipped and 600k shots administered as of today. Personally, I would lean toward delaying the booster dose of the vaccine for a few months and maximize the number of people who get the first shot. Essentially we can double the number of people vaccinated in the first 60 days. The trial data showed that after the first shot people were about 90% protected, and likely even those who do get infected have a mild case. I was having a discussion with a colleague of mine who was making the case that healthcare workers such as ourselves should not get priority and vaccine should go to the elderly and those with diabetes and obesity first, on the basis of the greatest good for the greatest number. I still think it is important to get healthcare workers vaccinated asap because we should not become transmitters to our vulnerable patients, and to keep us working instead of quarantining for 10 days if we do get infected. All hands on deck right now across the country. One of our other local hospitals apparently has one RN dedicated to moving the deceased to the temporary refrigerator truck they set up.
"Herd immunity" is the fraction at which the average infected person passes along the virus to less than one other person, causing the infection to peter out. To calculate that fraction you need to know the R, the average number of new cases an index patient will infect. Our behavior obviously can change R, and that can change the herd immunity number. R, with no social distancing, for COVID is between 2-3. This is much worse than influenza, which is only about 1.2, but much lower than measles which is 18. The herd immunity equation is 1-(1/R). At R of 18, you need about 95% of the population immune. For influenza you need about 15-20% (which is why the flu season tends to peter out at about 40-60 million infected). For COVID you would need 60% immune if R is 2.5. But with masks and social distancing R is around 1.2, so we could see benefit at 17% immune, meaning 50 million people. Now about 30 million people have already been infected, so if we vaccinated 20 million we would get benefit. If we vaccinate the right 20 million, we get the added benefit of collapsing mortality rather quickly. But the herd immunity target will change as we relax distancing and remove our masks, raising R, so we do need to get to 60% vaccinated by spring, if we want to go back to full normal. Things are pretty dark right now, but my mood has turned more positive. One last push, and we can get through this. I'm telling my residents, just suck it up for three more months. |
