The hang over from yesterday’s party over Moderna’s COVID vaccine results roiled pundits and the market. Obviously, the minimal amount of data released yesterday doesn’t allow anyone to make a definitive conclusion about whether the vaccine will work. I mentioned all these concerns in my post on the vaccine news yesterday, so today I don’t have to revise my comments since they were already tempered by the minimal information provided!
So, let’s talk about something more interesting and more positive. How would we use a COVID vaccine if it became available?
There are a number of suppositions we might make. First we would want to immunize individuals who were at risk, both occupationally and medically. Also, since we likely won’t have data on children, we would want to wait to administer the vaccine to them until there was clinical trial data about efficacy and safety. This is especially true since the infection appears to cause minimal disease in children.
So, who would we prioritize to get the vaccine first? Many have suggested immunizing healthcare workers given their occupational exposure. If this were the case, I would only immunize healthcare workers who had actual exposure to COVID. This would limit the population that needed to be immunized, at least initially.
The most important group from my perspective would be to immunize individuals at medical risk. Unless this population is protected, the vaccine is of little value. That is why clinical trials must include individuals over the age of 70 and those with complicating cardiac and lung problems. A vaccine given to younger, healthy individuals will eventually help the elderly at risk, but only when herd immunity is achieved for at least 50-60% of the country. That is likely to happen spontaneously over time, even without a vaccine. Therefore, the highest value would come from a vaccine that protects medically high-risk individuals.
I would also focus exclusively on individuals who have been screened and shown not to have antibodies against COVID. This means they have not yet been infected with the virus. I feel that it would be important, especially early on when the vaccine is scarce, not to immunize people who have already been infected and have protective immunity.
Another important reason not to immunize people who have immunity is that these people would not be represented in the clinical trial. We therefore wouldn’t know how the vaccine would react in these individuals, and this might lead to adverse events. Therefore, I believe that everyone should be screened for antibody first before administering the vaccine. This also makes financial sense given that these tests should cost much less than the vaccine.
It is a wonderful concept to think that we might have a vaccine even within 18 months. We do need to be thoughtful about using the vaccine once it becomes available.
For disclosure, I am involved in a company that is considering selling COVID antibody tests.