F1 sporting director Steve Nielsen has conceded to being "a little bit worried" and "nervous" ahead of a record-breaking 23-race calendar in 2022.
The Omicron variant of the Covid-19 pandemic has taken a stranglehold across the globe, leading to the reintroduction of tighter border controls that earlier this year had been relaxed.
That played a key role in F1 being able to fulfil a 22-race calendar this season, culminating in a thrilling climax to the championship battle between Red Bull driver and new title-holder Max Verstappen and Mercedes rival Lewis Hamilton.
Nielsen, who is responsible for the logistical side of F1, has expressed concern at the way Omicron has developed ahead of the new campaign that starts in just nine weeks' time with pre-season testing in Barcelona.
"I'd be lying if I said I wasn't a little bit worried," remarked Nielsen.
"I am because the optimism we perhaps had a couple of months ago, the pandemic was on the back foot, has been knocked back a bit.
"It's an ever-changing situation. Since the beginning, this thing has risen up and fallen away, depending on which region you're going in and we've had to tiptoe around those changing infection rates and try and fit it with our calendar.
"The only thing in our favour is obviously in 2020, the pandemic was new to every country.
"While it's still a terrible thing, the world is gradually learning to live with it, so some of the more severe restrictions we were seeing, certainly last year and the first part of this year, countries are putting more robust protocols in place and learning to live with the virus.
"Hopefully, it means they can continue to accept international visitors, which is obviously a massively important thing we need in order to be able to carry our championship on.
"We are nervous about it. I'm pretty certain we can do it with the calendar we have, but we will monitor it and we will react if we have to."
At this stage, there are no imminent changes to the calendar required, with a long-overdue return to Australia on the cards in early April following the cancellation of the events in 2020 and this year
Asked if there was a plan B, Nielsen replied: "Honestly, no, we're on plan A and we're not looking at any alternatives to plan A.
"If we have to, and because things change, we'll do that, but that's far away at the moment."