Read on Twitter
We've seen no evidence to support the claim that "nearly half of the accounts Tweeting about #COVID19 are likely bots.” 
with a few thoughts on the subject... https://www.npr.org/sections/coronavirus-live-updates/2020/05/20/859814085/researchers-nearly-half-of-accounts-tweeting-about-coronavirus-are-likely-bots
with a few thoughts on the subject... https://www.npr.org/sections/coronavirus-live-updates/2020/05/20/859814085/researchers-nearly-half-of-accounts-tweeting-about-coronavirus-are-likely-bots
First, we should get our terms straight: "Bot" means a lot of different things to a lot of different people — and doesn't necessarily refer to coordinated, manipulative, or inauthentic behavior. https://twitter.com/twittercomms/status/1263938177099689984?s=21
There are lots of different ways of using Twitter. Some people Tweet a lot; some never Tweet at all, or only Tweet sporadically. There's no right or wrong way to use Twitter — and many "bot" studies wind up dismissing a lot of real activity as inauthentic. https://twitter.com/ngleicher/status/1264614994475315200
Even if you take "bot" to mean "automated spam," there's little evidence that the dramatic conclusions of the #COVID19 study are accurate. https://twitter.com/conspirator0/status/1263538437333925888
That's not to say that spam isn't an issue. We know that discussions about #COVID19 are a prime target for all sorts of platform manipulation. Since March, our proactive systems have challenged millions of spammy accounts Tweeting about COVID. Learn more: https://covid19.twitter.com/
Our work to combat platform manipulation includes automated challenges (like reCAPTCHA), filtering from search and trends, and suspending accounts. Other than suspension, most of these actions aren't reflected in the feed of data that researchers access through our APIs.
Why not just suspend accounts immediately, or share information about our other actions in our APIs? Doing so would make it easier for adversaries to know we've caught them, and adapt to evade our detections.
We're proud to provide open access to researchers who want to study platform manipulation on Twitter and help us improve. Like all research, these studies should go through peer review and independent, external validation. https://twitter.com/alexstamos/status/1264643205292634112
We know that everyone from spammers to state-backed troll farms will try to target the most important conversations happening on Twitter. We're staying vigilant, and share the results of our work (and comprehensive data) on our Transparency Center. https://transparency.twitter.com/en/information-operations.html
