Lessons for Liverpool in the mass testing of Cambridge students [and for Dido Harding]

Nicholas Matheson does not have the qualifications of Dido Harding. He has never run a large private sector organisation, or sat in the House of Lords. He is merely an expert in virology and immunology.

Tom Whipple Science Editor www.thetimes.co.uk 

But as health chiefs attempt to roll out testing in Liverpool, they might learn from his experiences because he has mass tested the 10,000 students and staff of Cambridge University for a month.

In the summer Dr Matheson, the Baroness Harding of Cambridge, came to the same realisation that has informed the pilot test strategy in Liverpool. He argued that regularly testing all students would be the way to get through the winter.

The university agreed. Since the start of term, Cambridge has in effect operated its own parallel test and trace scheme. Like a scienceocracy it has also used the opportunity to experiment with long-mooted solutions.

Unlike the national programme, students are not analysed individually. They have been sending in swabs every fortnight, pooled with members of their bubble. If a bubble tests positive then it is locked down until they can get retested to identify who is infected.

This cuts down on tests but by checking twice it also catches most false positives.

So far, it seems to have worked: unlike other universities, none of which test at this scale, there have been no uncontrolled outbreaks.

The key to this approach, Dr Matheson said, and the reason Liverpool will be an important test case, is that more than half of cases are asymptomatic — people who would not volunteer for a test as they did not realise they had Covid-19.

Unless you can pick them up, preventing spread is extremely difficult. “We had a modest outbreak in one of the colleges,” he said. “The first few cases were picked up via the asymptomatic screening programme.

Joe Anderson, the mayor of Liverpool, on mass testing

“We like to think that by recognising the outbreak promptly we could limit the spread.”

While some universities have amplified infections and gone on to seed outbreaks into the community, the reverse seems to have been the case in Cambridge.

Since the second week, when positivity in asymptomatic tests peaked at 0.9 per cent of students, there has been a steady decline in cases. In the latest week, total positivity, including those presenting for tests because they had symptoms, had almost halved.

Dr Matheson acknowledges that making such a system work in a city will bring its own problems. A key lesson from the Cambridge scheme is that it needs support. Eighty per cent of students volunteered to take part, and because they are in college all can easily be followed up.

“We are generally supportive of the Liverpool approach,” he said. “We think asymptomatic screening is a good idea. But the devil is in the details.”