Antibody studies of Spain and France show just five percent of population has been infected

This news made me remember that study published in late March, in the first few weeks of the pandemic, guesstimating what the prevalence of the disease was in hard-hit European countries. This is where researchers believed things probably stood seven long weeks ago based on their model:

The eye-popping number was Spain’s, where 15 percent of the population was already expected to have been infected. Imagine what sort of prevalence there might be now after seven more weeks of transmission — granted, much slower transmission due to the nationwide lockdown, but still. Could Spain be creeping up towards herd immunity?

No, it turns out. A large national antibody finds actual prevalence at just … five percent. Between this result and the data from that study of MLB personnel earlier this week, suggesting one percent prevalence or thereabouts across the U.S., what’s left of the Oxford model’s theory of tens of millions of “hidden” asymptomatic infections?

The infection fatality rate there stands at around 1.2 percent, or 12 times more lethal than the flu. “We have not been surprised” by the results, said the country’s health minister. “There is no herd immunity in Spain.”

France has been testing its population for antibodies too. The results were similar.

A mere 4.4 per cent of the French population – 2.8 million people – have been infected, according to findings by the Pasteur Institue, published in the journal Science and based on models applied to hospital and death data.

Even in the worst hit parts of France, the eastern area and the Paris region, the infection rate only reaches between nine and 10 per cent on average, the research found.

Said French researchers, “Our results show that without a vaccine the herd immunity alone will not be enough to avoid a second wave at the end of the lockdown. Efficient control measures must thus be upheld after May 11.” France has recorded 27,074 deaths from the disease; if the antibody estimate is accurate, that would mean an infection fatality rate of just a shade under one percent. Optimistic estimates of the disease’s true fatality rate have been on the order of 0.5 percent or lower. The France/Spain data is bad news in that sense.

Given how dangerous COVID-19 appears to be, there’s a benefit to it not being as easily transmitted as modelers expected. The highest prevalence among any large population based on antibody testing that I can think of offhand is NYC, ground zero of America’s coronavirus nightmare, where just 20 percent or so of the population is infected despite the city’s outsized population density and reliance on mass transit. The relatively low prevalence in ultra-hot hot spots suggests that maybe we can hold down transmission with basic precautions like masks and social distancing (and eventually centralized quarantine?) while we wait on a vaccine.

It’ll only be another year. Or 18 months. Or much longer?