No, it hasn't really.
I suppose that more rigorous pre-screening would actually be more of a benefit to the travellers themselves and to the people who are on the journey with them. Clearly, if somebody is actively sick with something at that moment in time, and you could pick it up at a pre-screening just before the travel, something could be done then. The person could be treated and could recover before leaving on the journey.
I don't know that we've had particular problems specifically on that issue.