South Korea's Yonhap news agency said 2,238 people who had come into contact with Mers patients were in isolation as of Thursday, down from 2,451 the day before.
But it said South Korea had now gone two consecutive days without a new death.
On Wednesday, the country announced an ease on visa regulations for Asian visitors, in an attempt to stem the damage done to the tourist industry by Mers fears.
Officials say foreign visits in June were down 50% compared to the same period last year.