You may have seen this recent headline from the South China Morning Post

This was passed around widely as a troubling sign

This is very worrisome. Among recovered former #COVID19 cases, “nearly a third had unexpectedly low levels of antibodies. In some cases, antibodies could not be detected at all.” 🤔 https://t.co/VEwTJWOJD2 — Eric Feigl-Ding (@DrEricDing) April 8, 2020

However, “worrisome” was not even a good read of the results

The paper

In the preprint, the authors looked at plasma samples from 175 recovered patients all of whom had a mild course of the disease, requiring no ICU admission.

Firstly, the focus of the SCMP article was decidedly glass-half-empty

Important pre-print. First broad sero-survey of COVID19 patients. The data are great. I disagree with the focus. 94% of people made neutralizing antibodies!https://t.co/BYBRpKAMS3 — Shane Crotty (@profshanecrotty) April 8, 2020

Indeed, we see a wide range of measured antibodies

Most fairly high

So, I looked at this: https://t.co/6xl42BsUl4. Of course it is a pseudotyped particle entry assays. But out of 175 very few had no neut titers. Most were in the hundreds! Not sure what we worry about? https://t.co/OarfT4xU1n pic.twitter.com/bp799F0LWe — Florian Krammer (@florian_krammer) April 9, 2020

Among the study’s findings, emphasized in some commentary, was that older patients had more antibodies. It may seem unclear what to conclude from this, but one immunologist said

As an immunologist, this doesn’t worry me. Simply means that in these young people a rapid and precise CD8+ response cleared the virus by killing infected cells before a large enough burden to get specialized B cells involved.

There were also limitations to the focus of the study, as one physician pointed out

Only the covid-19 surface spiked protein was tested, which is unreliable. The more reliable nucleocapsid protein wasn’t.

An infectious disease physician points to another limitation

The authors’ definition of ‘very low’ (30%) is a titre of <1/500, and ‘undetectable’ (6%) as <1/40. But some data on coronavirus protective immunity in animals are with titres of 1/8 and 1/16…undetectable in these assays. So, yes, this is interesting, but no need for panic.

And finally, some interpreted this study as boding poorly for vaccine development, but at least one commentator saw the results as positive for vaccine development, though it may be premature to draw any conclusions