I recall 'chloroquine' being the subject of speculation when the WuFlu hit.
HTTP Error 429 is an HTTP response status code that indicates the client application has surpassed its rate limit, or number of requests they can send in a given period of time. Typically, this code will not just tell the client to stop sending requests — it will also specify when they can send another request.
https://blog.hubspot.com/website/http-error-429