I had my second dose of the Moderna m-RNA vaccine yesterday. What comes next?

It takes three weeks to build immunity, and I don’t plan to change what I’ve been doing until then. I have been isolating rather thoroughly. I haven’t been inside a store since last October. I’m taking piano lessons via Zoom. I wear double masks held tight with a clip that pulls the ear loops to the back of my neck. I haven’t seen friends in person since sometime late last summer. My family is at distances that make a year’s separation not extraordinary.

The CDC has promised guidelines on what to do after you’ve had your vaccine, but they haven’t published them yet. Guidelines are difficult to develop because there are so many variables.

Nature magazine, one of the top two science journals in the world, did a survey of 100  immunologists, infectious-disease researchers and virologists working on the coronavirus, asking if they thought that the virus would become endemic in the human population. Ninety percent of them said they thought it would. From just the mathematics of it, and the fact that it’s everywhere in the world now, I agree with that. I don’t see how it can be otherwise.

But that doesn’t mean that our current situation continues. People will be vaccinated; some will acquire immunity by being infected (although current guidance is that they should be vaccinated anyway); and more will continue to die. As immunity spreads, we will be able to relax social precautions, probably this summer or later. We will, perhaps in a couple of years, be able to go back to something like normal.

Dr. Fauci is warning us that it may take more than we thought to get to herd immunity. Now that anti-science Donald Trump is on the way out and Fauci is advising President-elect Joe Biden, he’s telling us what he thinks.

A year ago, we knew next to nothing about SARS-CoV-2. Since then, experts have bootstrapped us all the way to effective vaccines. The bootstrapping started from what we know about other coronaviruses and pandemics in general. It’s a matter of informed guesses, testing them against each other and observations, modifying them, and testing again.

Because the math of epidemiology is similar to the math of chemical kinetics, I’ve been following the modeling. It is also bootstrapping, guessing parameters, testing them, and modifying them. It’s a set of multiple parameters (an unknown number of them) being fitted to data that has serious limitations. The estimates get better as we get more data. That’s what Fauci is saying. Our first guess for herd immunity was around 70%. With almost a year of data, it looks like that could be as high as 90%.