4 Comments

Belated congrats on the birth of your daughter! Ours just turned 28 months. Parenting has been by far the most enriching experience of my life.

Expand full comment

People just liked it better that way.

Expand full comment

If a person or child already is confirmed to have had COVID and recovered, why is there no alternate protocol for them? Perhaps a single dose in "x" amount of time from recovery confers "y" level of protection equal to that of a two dose regimen. Maybe a chart of antigen titers and dosage regimens of the three vaccines?

I realize for simplicity sake a vaccine card says fully vaccinated or partially vaccinated.

But some would like the unneeded extra doses to go into arms that are willing in countries that have less vaccine readily available netting more fully protected people, but I know that isn't how it works because distribution logistics are complicated especially with the storage requirements and shelf life of mRNA vaccines etc.

Expand full comment

Right now it is very hard to confirm that a person has an appropriate level of protection, and there is wide variation in the immune responses to infection. What you're saying--using infection as a stand-in for a single dose of vaccine--has been proposed by several individuals, but it just isn't as straightforward as that.

To make it possible, we would need an easily-measured correlate of protection that could be used to confirm that a person is protected. The threshold level of this correlate would probably be different per certain patient demographics, and it is not super straightforward to assess what that correlate should be. Neutralizing antibodies are one candidate that has been proposed, but it is actually not that easy to assess levels of neutralizing antibodies. You need to do something called a virus neutralization assay--it can be done with a stand-in for the virus, but can also be done with actual SARS-CoV-2 virions as well--and then the same exact assay has to be used as the benchmark diagnostic in every testing lab everywhere. That's a relatively tall order.

The antibody tests that are on offer from various testing labs just look at reactive antibodies, not neutralizing ones. While neutralizing antibodies are a subset of the overall SARS-CoV-2 reactive antibodies, it is not at this time clear what the relationship between overall anti-SARS-CoV-2 spike antibodies and neutralizing anti-spike antibodies may be. There has been some work on this, but it is not yet at a place where we can use it clinically for reliable diagnostics.

Then of course there is a question as to whether the numbers might be different in children and adults, because of the difference in disease severity seen by age. We would need to make sure that the correct correlate threshold is being used.

There are a lot of unanswered questions to be addressed in the push towards being able to test someone for immunity, but the ability to do that is, in my opinion, one of the biggest unmet needs in COVID-19 control today.

Expand full comment