Some students may have lost so much learning this year that it will be "difficult" to award them a grade at all this summer, a GCSE and A-level exam board has said.
Jill Duffy, chief executive of OCR, said that while it may "seem harsh" for teachers not to award students grades, it would be equally wrong for them to progress on to courses they are not ready for.
"It is imperative that we are entirely honest that there may be some young people, albeit a small number, who have lost so much learning that it will be difficult to award them a grade at all," she said.
"This may seem harsh, but it would be very wrong to place someone on a course for which they are ill prepared, where they will struggle to keep up with their peers, and which they may not complete."
Ms Duffy added: "We will need to provide whatever it takes to give these young people, who will be in the minority, the chance to catch up.
"This could be through a summer school, or it could be that such students, if they wish, should have the opportunity to retake a full year of study."
She acknowledged that some people may feel "intuitively" that the result of Covid learning loss "is unfair".
"We need to have a public discussion about this now, not after results have been issued," Ms Duffy said. "There is a risk that the most disadvantaged will lose out the most as a result of this approach and we need to consider very carefully what that might mean this summer."
Speaking at a Westminster Education Forum conference on the impact of te coronavirus on the exams system yesterday, she also said that while the pandemic had led to growing calls for change in the education sector, it would be wrong to scrap GCSEs and A levels.
"There are calls to scrap GCSEs and questions about the future of A levels but both have been an extraordinary national success," she added.
"They have longevity and have value because they have evolved and adapted to the changing educational and social needs over the past 50 years – there are no reasons to think that they cannot evolve again, driven by the very best evidence about quality," she said, although she said that the "time for a debate is becoming due".
There have been growing calls to scrap GCSEs during the pandemic.
In November last year, Dame Alison Peacock of the Chartered College of Teaching said that the chaos over last year's exam grading revealed "how flawed our assessment system is", adding that "there’s a real consensus beginning to build that potentially we don’t need GCSEs any more".
But in January, Cambridge Assessment – which runs the OCR exam board – said that GCSEs gave students and teachers a "focus" and clarity over learning expectations.