The exam watchdog, responding to concerns about coronavirus, is telling schools in England to keep preparing as usual for the summer exam season.
Ofqual says it is working with exam boards and the government to make contingency plans if there is a "widespread outbreak".
But until that becomes necessary, the watchdog is telling schools to assume exams will continue as scheduled.
Most GCSEs and A-level exams are planned to run from early May.
On Monday, Ofqual issued advice that "students, schools and colleges should continue to prepare for the summer exams and assessments as usual".
But it said there would be guidance to "manage any particular risks" to the exam season if coronavirus became widespread.
The watchdog said it would send any updated information when necessary - and also shared existing contingency plans for exams being disrupted.
This covers emergencies that might happen during the exam season - which could see pupils having to take an exam in a different location from their own school or rearranging the time of an exam.
But these responses are usually for problems facing a small number of individual schools, pupils or staff.
So far, more than 20 schools have been closed at some point in response to concerns over coronavirus - and others have sent home pupils, such as those who had returned from a half-term trip to an area with higher levels of the virus.
In the most recent cases involving the virus, there were reports of a member of staff infected in a primary school in Tetbury, Gloucestershire, and in an infant school in Woodley, Berkshire.
But some of these schools will have returned to normal - and the great majority of the school system, with more than 24,000 schools in England, does not seem to have been significantly affected by the virus.
With the exam revision season already bringing its own stresses, ASCL head teachers' union Geoff Barton said: "Schools and colleges will be approaching the possibility of the coronavirus situation disrupting exams in a calm and measured manner, hoping for the best and preparing for the worst.
"We would urge students to focus on studying for their exams and not to worry about what may or may not happen."
National Association of Head Teachers leader Paul Whiteman said: "Our best advice to school leaders is to encourage them to stay on top of the continually updated advice from the government, share it with pupils and their families and act accordingly."