If you’re still hopeful about herd immunity and the Oxford model, in which many millions more people than thought have asymptomatic cases of the virus, here you go. The Swedish government is right there with you.

The Swedish Public Health Agency has collaborated on a new study that estimates one-third of all Stockholm residents will have been infected with COVID-19 by May 1. That amounts to approximately 600,000 people in Sweden’s capital city. Sweden’s official figures report only 15,322 positive cases so far in the whole of the country, suggesting significant numbers of “invisible” infections. The astonishing numbers are in stark contrast to the latest World Health Organization (WHO) estimates that “no more than two to three percent” of the world’s population have been infected… The study indicates that for every confirmed case of COVID-19, a further 999 people are likely to have been infected with the virus without knowing it. The study used a model that includes the number of positive COVID-19 cases in Stockholm from February 17 to April 10, along with samples taken from infected people in the period March 27 to April 3.

The (heavily criticized) Stanford study of Santa Clara County in California made waves a few days ago by estimating that the true number of infections locally may be 50 to 85 times greater than the number of confirmed cases. This Swedish study is suggesting that the ratio of actual infections to confirmed cases in their country might be more like a thousand to one.

Which is hard to compute. There are 15,322 confirmed cases in Sweden. At 1,000 to one, we’d expect 15.3 million actual infections. The total population is 10.23 million.

I don’t understand how the Swedish and Stanford models can diverge so dramatically. Even allowing for the fact that Sweden should have higher rates of transmission than other western countries because, uniquely, it’s resisted lockdowns and school closings, we should logically expect to see a higher number of deaths per capita early in their outbreak too. And we do see a big number — they’re seventh in the world in deaths per million people. But that’s only about a third of Belgium’s number and less than half of Spain’s and Italy’s. How is Sweden pulling off a singularly high infection rate with a not so singularly high death rate?

One possibility is that their infection rate isn’t actually singular. Maybe hot spots in Italy, Spain, and Belgium are also much further towards herd immunity than anyone suspects right now. And … New York? Nate Silver is intrigued by the data suggesting that New York’s infection rate has fallen below 1.0, which can be the result of a comprehensive lockdown — or herd immunity.

New York City had *seemed* have an R of around 0.9, with a fairly slow decline from a plateau. But the decline has accelerated in the past week or so and the past few days of testing data suddenly makes it look more like an R of 0.7. More like 0.8 in the suburbs and 0.85 upstate. — Nate Silver (@NateSilver538) April 21, 2020

Yeah, it is not crazy to ask questions about this stuff, particularly given how we're now seeing notably steeper deceleration in NYC than upstate. https://t.co/22o2Nvkiae — Nate Silver (@NateSilver538) April 21, 2020

I wrote a week ago about a study of pregnant women at a New York City hospital in late March and early April that showed 15 percent who were admitted to give birth were infected with COVID at the time of testing. Nearly 90 percent of them had no symptoms (yet?). If that 15 percent figure was representative of the city’s population circa April 1 (which is a biiiiiiiig “if”), is it possible that 33 percent of New Yorkers will be infected by May 1? Bear in mind, the study of pregnant women said nothing about whether the other 85 percent of women tested may have had the virus previously and cleared it from their system before arriving at the hospital. It was a PCR test (e.g., nose/throat swab), not an antibody test. Conceivably the total number of women who’d had coronavirus at some point prior to admission to the hospital could have been higher than 15 percent.

Seems like we could really use some extensive antibody testing of New York to resolve this question. And soon, as the head of the CDC is warning that the second wave this fall could be worse than what we’re dealing with now. Why? Because in the fall we’ll be coping with two epidemics, not one.

“There’s a possibility that the assault of the virus on our nation next winter will actually be even more difficult than the one we just went through,” CDC Director Robert Redfield said in an interview with The Washington Post. “And when I’ve said this to others, they kind of put their head back, they don’t understand what I mean.” “We’re going to have the flu epidemic and the coronavirus epidemic at the same time,” he said. Having two simultaneous respiratory outbreaks would put unimaginable strain on the health-care system, he said… In the coming summer months, U.S. health officials need to persuade Americans to think ahead to the fall and the importance of getting flu shots. That way, public health officials can minimize the number of people hospitalized from flu. Getting a flu vaccination, Redfield said, “may allow there to be a hospital bed available for your mother or grandmother that may get coronavirus.”

One thought: If the virus really is as wildly contagious as Sweden suspects, and as prevalent in NYC as we’re speculating, then the idea that there’s some special “blue state” explanation for why New York has been especially hard hit is a hard sell. Things like population density and subway crowding may explain why it’s been hit *faster* than everywhere else but we should expect the same ~0.5 percent fatality rate in red states as they build towards herd immunity, albeit much more slowly. (I’m calculating the fatality rate in NYC on the assumption that a third of the population has been infected to this point.) The fact that more rural areas have avoided heavy impact so far would be no reason to assume that that’ll continue. It should be New York all over again, but in slow motion.

In lieu of an exit question, for your amusement, here’s Don Lemon freaking out about anti-lockdown protests. Trump said at today’s briefing that, from what he’s seen of the protests, the participants are being responsible and practicing social distancing. Not true, my man. And he’s inviting a round of bad publicity for the demonstrators in the media by giving reporters a reason to focus on their irresponsibility.