How many students arriving at UK universities this term are Covid-positive?

Number 103: #USSbriefs103

Andrew Chitty
Published in
5 min readSep 21, 2020


Andrew Chitty, University of Sussex

Photo by LOGAN WEAVER on Unsplash

In the last week the first outbreaks of Covid-19 among students have been reported at four UK universities: Oxford Brookes, Edinburgh Napier, Bath and Manchester Metropolitan. But there are already anecdotal stories of multiple cases at many more universities, and there is a natural suspicion that these official reports are only the tip of an iceberg.

To know how likely more outbreaks are, we need to know how many students arriving at UK university towns and campuses will be Covid-positive. This Brief introduces a spreadsheet ‘Estimated numbers of students arriving at UK universities this term with Covid-19’, which estimates this number for students arriving today (21 September) and on the next two Mondays (28 September and 5 October).

It also estimates. for each of these three dates, how many of those who are Covid-positive will be currently asymptomatic, and also crucially how many will be both currently asymptomatic and infectious.

The spreadsheet focuses on students because they are far more numerous than staff, because unlike they are moving into new large shared households, and because they tend to socialise much more widely than staff. So they are the most likely vectors for transmission once term begins.

Its headline results (rows 197–198 of the spreadsheet) are that as of today, 21 September:

  • about 14,000 students due to return to UK universities (6 in every thousand) are currently Covid-positive
  • of these about 9,000 (4 in every thousand) are currently asymptomatic
  • of these in turn about 3,500 (1.5 in every thousand) are infectious
  • this last number could be as low as 2,000 or as high as 6,500

The above numbers will increase by about 50% by next Monday (28 September) and will more than double by the following Monday (5 October). This is ignoring the almost inevitable increases in infection rates over the next fortnight among students who have already arrived at university towns and campuses.

The crucial number is that of those who are both currently asymptomatic and infectious. These are by far the most likely to pass the virus to others, since they have no way of knowing that they are carrying it. In the conditions of student life, the chances of any one of them starting an outbreak are very high. With somewhere between 1,000 and 4,000 students already in this category today, it is hard not to conclude that the HE sector will suffer multiple large outbreaks of Covid-19 within weeks. These outbreaks will have serious consequences for the long-term health of students themselves, and possibly severe consequences for the short-term health of the staff they may inadvertently pass the virus to in seminars and at library desks; of the other members of the local community they may pass it to while shopping or on public transport; and of the relatives they may pass it to when going home during term.

The spreadsheet does not attempt to predict the spread of infection once students have arrived. However Brooks-Pollock et al (14 September) have modelled the progress of Covid-19 infection at Bristol University in the course of the autumn term based on students home location and the prevalence of the disease in their home location in July. They estimate that, with the university following Public Health England guidelines but continuing to teach face to face, prevalence would grow with a doubling time of 9 days, corresponding to a daily growth rate of 8%, and that by the end of term 5,700 students (20% of the whole student population, with a confidence interval of 3,900 to 7,400 students) would be infected. By way of preventing this outcome, they find that ‘reducing face-to-face teaching is likely to be the single most effective intervention’.

By now it is too late to prevent the migration of between one and two million students to university towns and halls of residence over the course of this month, and the inevitable multiple outbreaks that will result. But universities have it in their power, following the various leads of Birkbeck College, University College London, Queen Mary University of London, St Andrews and Manchester, to mitigate this outcome to the maximum by taking all teaching online this term, and by simultaneously announcing that they will release all students who decide they do not want to move into university accommodation from their contracts. No doubt this will cause financial losses. But in the face of a disease that is lethal for some and, regardless of age, causes prolonged debilitation for a significant proportion, universities’ duty of care to their students, their staff and their local communities must take absolute precedence.

Note on methodology

Essentially the spreadsheet takes

  • the estimates of English case prevalence on 10 September from the Office for National Statistics
  • the relative recorded incidences in the four UK nations in the 14 days to 10 September from the government Coronavirus website
  • the estimates of age group prevalence in England on 10 September from the Office for National Statistics
  • the rate of growth of symptomatic prevalence from 10 to 18 September from the Covid Symptom Study, and
  • the numbers of students at each UK university from HESA 2018–19 data

From these it estimates, at each university, on each of the above three dates, among students at the university:

  • total cases of Covid-19 on that date
  • currently symptomatic cases
  • currently asymptomatic cases
  • currently asymptomatic and infectious cases

For currently asymptomatic and infectious cases the spreadsheet gives midpoint, lower bound and upper bound estimates.

The spreadsheet ignores non-UK students on the grounds that those who have come from countries where there is any significant prevalence will be asked to self-quarantine on arrival.

For more details see the notes on the spreadsheet.

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Additional notes 22 September 2020

(1) In the Note on Methodology I have now replaced the words ‘the relative recorded incidence across different age groups on 7–14 September from Public Health England’ by ‘the estimates of age group prevalence in England on 10 September from the Office for National Statistics’. The previous text was included by error.

(2) I understand from colleagues at the University of Manchester that the university’s present policy is to offer a large proportion of face-to-face (in-person) teaching this term. I apologise for this error. The section ‘What will semester 1 look like?' on the Manchester page to which I linked in the Brief was difficult to interpret.

(3) It has been pointed out to me since the publication of the Brief that Jess Enright (Glasgow) has been running calculations on github similar to the ones introduced in this Brief, using a set of sources overlapping with my own.

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This paper represents the views of the author only. The author believes all information to be reliable and accurate; if any errors are found please contact us so that we can correct them. We welcome discussion of the points raised and suggest that discussants use Twitter with the hashtag #USSbriefs103 ; the author will try to respond as appropriate. This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.



Andrew Chitty

Senior Lecturer in Philosophy, University of Sussex