Airbnb said Thursday that it narrowed its second-quarter loss to $68 million and saw an increase in bookings, but the company warned that new variants of COVID-19 will make future bookings and cancellations harder to predict.

The San Francisco-based home-sharing company’s stock fell more than 3% in extended trading.

Airbnb’s business has picked up along with the recovery in travel that, at least in the U.S., began early this year as Americans began to get vaccinated against the coronavirus. Many vacationers have looked to avoid crowds and steer clear of hotels, creating an advantage for Airbnb and rival Vrbo.

The home-sharing companies are less reliant than hotels on business travelers, who have been much slower to get back on the road.

The recent surge in COVID-19 infections could slow the travel recovery, however. Last week, Expedia Inc., which owns Vrbo, reported that travel dipped and cancellation rates rose in July, and that the outlook for travel remains uncertain.

Airbnb’s second-quarter loss compared with same-quarter losses of $576 million last year and $297 million in 2019.

Revenue rose 10% over 2019, to $1.34 billion, roughly in line with analysts’ forecast of $1.26 billion. Airbnb said it expects to post record revenue in the third quarter, “well above” the 2019 peak.