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The SAGE files: One in 20 Covid-19 patients is infectious after 14 days, report finds

Boris Johnson was warned confusion about the Covid-19 alert level may spark ‘public anxiety’ days before eased lockdown, secret papers published today revealed.

SAGE scientists urged Number 10 to be clear about the threat level of coronavirus in a report submitted to ministers on May 26.

It came two days before the Prime Minister reopened schools, outdoor markets and car showrooms, and told a chunk of the workforce to return to work.

At the time, the coronavirus alert level was at a four, meaning the virus was growing exponentially. Government scientists urged ministers not to ease lockdown until this had come down to level three.

In the SAGE report, scientists said: ‘People need to know what to do at a particular alert level and how to prepare for a change in Alert Level.’

‘If it is not clear what to do when an Alert Level increases, it is expected that levels of public anxiety will increase.’

In a public service announcement that was criticised for being confusing, Mr Johnson told the British public that the UK was currently at level four, but was ‘moving towards level three’.

The SAGE report specifically warned against this kind of mixed-messaging, adding: ‘For clarity of public communications, Alert Levels should be a simple step level system with no sub-division.’

Some 31 documents were today published by the Government Office for Science, which is headed by Sir Patrick Vallance, England’s chief scientific adviser.

The SAGE papers are being released in a bid to show greater transparency from the Government. 

They are among dozens in a tranche of papers presented to SAGE, the Government’s Scientific Advisory Group for Emergencies, over recent months to help guide ministers through the crisis.

And the reports detail all the scientific advice which is being presented to decision-making officials who dictate when and how the country moves out of lockdown.  

Files released today revealed scientists told the Government:

About 5 per cent of patients ill enough with coronavirus to be admitted to hospital are contagious to others after two weeks, two separate SAGE reports found.

Two teams of Government scientists submitted papers to ministers on May 28 warning some sufferers had high enough viral load to infect others for 20 days. 

They reviewed the available evidence from around the world looking into viral load in hospitalised patients with the disease, as well as new UK research on British patients.

The team of virologists and infectious disease experts – which included Professor Peter Horby, an epidemiologist from Oxford University – found most people are not infectious 12 days after symptoms start. 

‘However, a very small minority of hospitalised individuals might remain infectious until day 20’, they write, adding that many of these patients will be elderly.

They warned that this finding poses a ‘risk for onwards transmission to carers’, care home workers and family members who may then go and pass the disease onto others. 

The scientists recommended that people working in high risk areas like care homes, as well as care home residents themselves, be given swab and antibody tests after recovering from the virus before returning.

A high level of antibodies in the blood ‘is likely to correlate with a low probability of infectiousness’, the researchers say.

The swab tests currently being used in the UK to diagnose coronavirus can miss infected people up to a fifth of the time, according to a paper submitted to ministers this month.

The UK’s Covid-19 testing programme uses a network of laboratories to detect SARS-CoV-2 in nasopharyngeal swabs, which take samples from the throat and nose.

SAGE researchers said these swabs – the gold standard of testing currently- are 95 per cent sensitive and specific.

This means that, under laboratory settings, they are correct more than nine times out of 10.  

But errors in the way samples are collected in the community and transported to laboratories can bring down their accuracy significantly. 

For this reason, ‘the UK operational false positive rate is unknown’, the experts said, and ‘there are no published studies on the operational false positive rate of any national COVID-19 testing programme.’

They used a model which combined results from seven studies and more than 1,300 swab tests to create a model of the the false negative rate for the test.

The model suggested that in the first four days of infection, when a patient is pre-symptomatic, the tests can give a false positive up to 67 per cent of the time. 

This is because the virus has not yet had time to duplicate inside their respiratory system, making it hard to pick up by the test.

The chance of a false negative then dropped to 38 per cent on day 5 – the day when most people get symptoms. 

By day eight, the tests were 80 per cent accurate, meaning they gave a false negative one in five times to people who had symptoms for at least three days.  

The researchers recommended the Government launches an independent quality assessment review of the testing programme to make sure its fit for purpose.

They also said negative results that allow people to return to work, leave hospital or come out of isolation should be ‘treated with extreme caution’.

These people should self-isolate for 14 days regardless of the test result, the experts advised. 

Reacting to the SAGE paper, Professor Rowland Kao, an epidemiologist at the University of Edinburgh, said: ‘The report that up to 20 per cent of PCR tests may be falsely negative reflects the many operational challenges associated with correctly doing the test ranging from the initial collection of the sample, through to potential issues with storing or transferring the sample taken, or the laboratory procedures to interpret the sample. 

‘It’s important to remember that the test does not have to be perfect in order to be an effective component of disease control. All that is necessary is that the combination of measures taken have to be sufficient to keep the R number below one. Therefore maintaining those other measures, including social distancing and self-isolation, remain important even if with an extensive testing capability.’

Boris Johnson’s plea for Britons to stay away from pubs, bars and restaurants in mid-March fell on deaf ears, a poll submitted to SAGE revealed.

A YouGov survey between March 17 and 18, a week before lockdown, showed more than half (55 per cent) of adults were still eating and drinking out.

Forty-five per cent said they’d stopped altogether and 17 per cent said they’d reduced the amount of times they attended the establishments.

Mr Johnson was adamant not to put the UK into lockdown, as the rest of Europe had at the time, and instead tried to use public messaging on social distancing and hand washing in early March to curb the spread.

But the YouGov poll, along with alarming predictions that hundreds of thousands of people would die from the virus, forced him to impose the nationwide quarantine. 

The survey also found that just 27 per cent of people stopped seeing family from other households. 

Just over a third (35 per cent) of the public, and more than half (59 per cent) of full-time workers were still going to work as often as before.

Only 16 per cent of children had stopped going to school by March 18.

A University College London paper submitted in late May warned the Government that there were several institutional settings at high risk of suffering clusters of infections.

The team said that, as well as hospitals and care homes, cruise ships, prisons, homeless shelters, migrant centres, factories and long-stay mental health facilities were vulnerable. 

This is because they are enclosed institutions which act as ‘reservoirs of infection’, house vulnerable individiuals and often include individuals who are less inclined to seek treatment or find it difficult to access healthcare (such as the homeless and migrants).

The report offered one piece of evidence – drawing on data from the US, France and UK which suggested homeless shelters housed up to a third of residents with Covid and up to 15 per cent of staff with the disease.

But the report was primarily a warning based on other reports. The researchers said it was important these ‘forgotten institutions’ were provided with adequate PPE, clear social distancing instructions and that more surveillance studies be launched into them. 

On May 28, SAGE used the UCL report to advise the Government ‘strongly’ that identifiying these high risk areas and implementing preventative measures in these places must be ‘proactive’.

SAGE urged the Government to raise awareness about the risk of catching Covid for people in certain jobs.

Office for National Statistics figures have shown that shop assistants, taxi drivers, factory workers and other public-facing workers are being disproportionately killed by Covid. 

Scientists said these people should be targeted through public health messaging, telling them to ‘pay particularly close attention to the social distancing and hygiene recommendations ‘.

It is vital that the responsibility for managing infection risk due to multiple contacts is shared between the people at risk and their employers, SAGE said.

Wherever possible, changes to the structuring of workplace activities and environments should be prioritised, they said.

This would include ‘taking extra care to manage infection risk may also involve everyone concerned undertaking additional actions such as handwashing at appropriate times, avoiding touching face or surfaces, cleaning all shared surfaces, changing/washing clothes, using and disposing of tissues, ventilating shared spaces, social distancing, wearing a face covering when close to others if social distancing is not possible’. 

The Government has been told that coronavirus health messages tailored specifically for different ethnic groups are ‘particularly important’. 

Ministers were recommended to give people from BAME backgrounds – who are disproportionately affected by the virus – extra advice on how to stay safe during the crisis. 

The advice is outlined in a summary of a discussion on ethnicity and Covid-19 risk, endorsed SAGE on June 4.  

The Sage summary said: ‘Work was discussed that highlighted the importance of faith practices, differences in patterns of healthcare usage, willingness of communities to engage with prevention, and other factors such as access to outdoor space. 

‘Different messaging, including health messages tailored specifically for different ethnic groups was highlighted as being particularly important.’  

Two reports have been published by Public Health England (PHE) in recent weeks which suggested BAME communities are dying from Covid-19 at greater rates than people in white ethnic groups. 

The earlier findings from PHE said that people of Bangladeshi heritage were dying at around twice the rate of white Britons. 

It also found that other minority ethnic groups were at up to 50 per cent higher risk of dying. 

The second report pointed to a raft of recommendations from stakeholders, including the need to develop ‘occupational risk assessment tools that can be employed in a variety of occupational settings and used to reduce the risk of employee’s exposure to and acquisition of Covid-19’.

This is especially true for BAME workers in health and social care and on the front line in occupations that put them at higher risk, it said.

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