More than 50 universities in the UK have confirmed cases of coronavirus as thousands of students return to campus.
Nearly 1,800 Covid-19 cases have been identified among university students and staff, a survey suggests.
A surge in coronavirus cases in recent weeks has led to thousands of students having to self-isolate in their halls at some universities – including Manchester Metropolitan and Glasgow University.
There have been more than 200 cases at the University of Sheffield and 177 University of Liverpool staff and students have tested positive, according to a PA news agency survey which contacted 140 institutions.
Around 56 universities across the UK have had at least one confirmed case of Covid-19, an analysis of university responses and media reports suggests.
At least 1,798 positive cases of Covid-19 have been identified at these universities, the analysis suggests.
The findings come as the University of Manchester – where there have been 221 cases of Covid-19 – apologised for "conflicting information" given to students from some residential staff about isolation.
The BBC reported that students were told that a member of an isolating home could go to the shops for food if they could not get deliveries, and they could use laundry services as long as they wore a mask.
A university spokesman said: "The safety and wellbeing of our students is our main concern. We are proud of the work carried out by our Residential Life Team who live in halls alongside our students.
"If some members of that team have issued conflicting information, we apologise. All students have now been sent a single clear message."
The highest number of cases among students and staff appear to be in northern cities in England as well as Scottish universities – which reopened first – but there have been cases at institutions across the UK.
There have been 47 cases among students at Oxford Brookes university, while at Sussex University one member of staff and 10 students are self-isolating after testing positive for Covid-19, the PA survey shows.
But not all cases among students and staff have been reported "on campus". Some have occurred in local communities or in private halls of residence.
Hillary Gyebi-Ababio, vice president for higher education at the National Union of Students (NUS), said: "The rise of Covid rates at universities needs drastic action now.
"It is deeply irresponsible to continue with business as usual and the government and universities must be honest with students about what the pandemic can mean for their university experience."
She said: "Fully accessible online education must become a reality immediately and we need digital investment at a national scale to make this happen."
Nick Hillman, director of the Higher Education Policy Institute (Hepi), said: "It is a stressful and difficult time for students at the moment and no one would have wished this particular start to the academic year.
"But we also need to recognise that the number of students with positive tests and also the number self-isolating is a tiny proportion of the total UK student body.
"Universities do need to support students that are self-isolating and, much – but not all – of the time, that support seems to be getting to where it is needed."
Jo Grady, general secretary of the University and College Union (UCU), said: "It is an outrage that ministers and universities spent the summer talking up a student experience that the science and staff said was never likely."
She added: "The priority for ministers now must be a support package that underwrites lost income for universities and provides vital protection for staff and students."
A Universities UK (UUK) spokeswoman said: "It is important to keep these figures in context: there are 2.8 million staff and students at UK universities.
"Multiple measures are in place to promote safety, health and wellbeing on campuses to reduce risks and minimise disruption.
"Where it is necessary for students to self-isolate, universities are taking care of both their physical and emotional wellbeing including access to testing and health care, mental health support, continuing learning online, safe social interaction, food deliveries, laundry, and financial support.
"Universities are currently working in partnership with their local authorities, public health bodies and others to ensure that effective and outbreak response plans are in place and clearly understood."