In some pockets of the United States, if you squint hard enough, the coronavirus pandemic might feel like it’s almost over.

In an hour-long interview that’s been edited for length and clarity, I asked him about why he thinks it’s too late to hope for herd immunity, and what he thinks we need to be doing now in what looks to be a long fight against a Forever Virus.

First and foremost, a virus that infects multiple species, animals and humans, and a virus that has multiple new variants, each one having the potential to reinfect people, is sort of disqualified from being a candidate to be eradicated.

Because in both cases, the denominator keeps changing, of how many people could be exposed to the disease.

If you’re exposed to or get vaccinated against the disease and then a new variant comes in that can still infect you, the concept of herd immunity no longer really applies.

And if animals—and we’ve got 12 different species who’ve been infected with COVID-19, usually from humans—if they can harbor it, and then infect humans, then you can’t eradicate the disease like we’ve been unable to eradicate yellow fever, because monkeys get it and they just don’t like to put their arms out to get vaccinated, and it’s really tough to get them to stand in line?

How should Americans who’ve been vaccinated and are feeling a sense of relief and maybe going inside restaurants again or sending their kids under 12 to camp for the summer be thinking about all this and their behaviors.

Those of us who’ve been vaccinated, I think many would share the feeling I had when I had my second dose, and just felt like a load was off my shoulders.

It’s the best of times, because we’ve got the vaccines, and it’s the worst of times, because of the people who don’t have the vaccine.

You can’t help but look at the funeral pyres burning in India and Nepal and contrast that to Americans, joyfully ripping off our masks and going to the beach for a summer holiday, without understanding that it’s a tale not of two cities but of two worlds, and two lived experiences.

In my county, Marin County in California, when I looked a couple of weeks ago, 30 percent of all the cases here were the British variant, the B.1.1.7, and that’s the alpha variant, but we also had the beta and gamma and delta, the others that we call variants of concern.

What makes a new variant succeed is that it outpaces all the prior variants, all the ancestral strains, and then infects all the people we have in our community who haven’t been vaccinated.

What we fear the most is that kind of a variant that will infect people who’ve already been vaccinated, and that the vaccines will turn out to not be effective against it.

And we have a reason for concern: that we already have one vaccine that, when matched against one variant, becomes 90 percent ineffective.

I don’t think that’s a very high risk—it’s not a 50 percent risk, but it’s a non-zero risk, and Harry, if I told you that there was a 5 percent risk that if you drove from wherever you are to the closest Starbucks, that you’d be killed in that car, you wouldn’t go!

Now, as things are reopening here, and with these concerns you’re talking about looming, what can we be doing to brace for what could be coming with a variant or the next pandemic.

We should realize that if 30 percent of Americans are not vaccinated, that’s 120 million people.

That’s the term I’m borrowing from the Japanese, who use it to define teams that are mobile, that have highly computerized systems to have a situational report like a battlefield commander would have or like a CEO would have, and can see where every variant is.

Because this virus is going to be with us for years or decades, and the variants are likely to return, and there will be new pandemic viruses?

Why not have sewage sampling everywhere, especially in the cities, and be able to do virus sequencing to know what the variant is.

And the worst part, and the hardest part, is we’ve got to put it together at a time when everyone is feeling like we’re through with this disease, we’re over it, we can go to the beach.

If it’s any consolation, in every pandemic, almost every country has been secretive about whether they were infected or not.

It’s always the case that people hide diseases in a pandemic, and especially in wartime.

But you are never going to have a vaccine on the day that a novel virus leaps out from a chimpanzee or a mink to a human.

If you’re lucky, you have an antiviral if it’s a virus that’s been hanging around on a shelf from some other disease, but you’re probably not going to be lucky.

Every year, we’re facing the drip, drip, drip of the risk of another pandemic.

We might as well use this one to get good at it, because this risk is not going away.

If a third of the population, 30 percent, is not vaccinated, not wearing masks, and we’ve already got the variants in the United States—what do you think’s going to happen.

Remember, what drives a virus is not how good we’ve been at vaccinating 60 percent.

It’s the 120 million Americans who are not vaccinated, not wearing masks, not practicing social distancing, and who are congregating.

And it only takes one little virus, and it’s everywhere, because they’re just not protected.

Of those who aren’t vaccinated but had the virus, a high percentage have already lost their immunity or have waning immunity—there’s much less and much less durable immunity from getting the disease than from getting the vaccine.

And it’s true that if we don’t have any viruses anywhere in the country, those states will get the derivative benefit of the prudence of other states, but I wouldn’t want to bet on it?

By the way, I’m pretty optimistic that we’re going to get a handle on this disease, that we’re going to have booster shots, and we’re going to shame or convince the world to help build vaccine manufacturing plants all over the world.

But you mentioned earlier, because of nationalism, because of people focused on their own community, we misunderestimate this virus.

We don’t understand that we’re all just meat, and it travels everywhere?

We weren’t going to declare it eradicated until two years would have passed after the last case.

And on average, it took six months to find any virus with pandemic potential that spilled over from animals.

It gives you the appearance of more outbreaks, but it gives you time to respond to bird flu or swine flu or a coronavirus or whatever the next pandemic is going to be.

It’s a bloodborne disease, or it’s a disease spread by sharing vital fluids, and there’s no asymptomatics, and it kills a lot of people who get it.

So if you were a virus and choosing the attributes that you wanted, smallpox would be ideal, because it spreads like wildfire and is to some extent more contagious than the original COVID-19, and it kills one out of three.

It’s the definition of the number of secondary cases that come from a primary case, which tells you, because this virus is going to spread at exponential speed, it tells you what’s the exponent.

So if R naught is 10, as it is for measles, herd immunity is one minus one over 10, or 90 percent of people have got to be immunized.

If R naught is two, then it’s one minus one over two or 50 percent of the population.

The theory is that what drives an epidemic is the density of susceptibles, it isn’t the number of people who are vaccinated.

So if a disease transmits very slowly, it doesn’t infect very many people, then you don’t have to vaccinate that many people to stop it.

Early on in the epidemic, when the first report out of Wuhan was that the R naught was 2 or 3, people were saying how we could get to herd immunity with only 50 or 67 percent of the population vaccinated.