A code error in the NHS Covid-19 app meant users had to be next to a highly infectious patient for five times as long as the NHS had decided was risky before being instructed to self-isolate, the Guardian has learned.
What you can and can’t do in England’s new national Covid lockdown
New national restrictions are due to come into effect in England on Thursday, after MPs vote on them, and remain in place at least until 2 December.
What can I leave home for?
- For childcare or education, where it is not provided online.
- To go to work unless it can be done from home.
- Outdoor exercise either with household members or with one person from another household.
- For all medical reasons and appointments.
- To escape injury or harm, such as domestic abuse.
- To provide care for vulnerable people or volunteer.
- To shop for food and essentials.
- To see people in your support bubble.
- Children will still be able to move between homes if their parents are separated.
Government say the list is not exhaustive, and other permitted reasons for leaving home may be set out later. People could face fines from police for leaving their home without a legally permitted excuse.
Can different households mix indoors?
No, not unless they are part of an “exclusive” support bubble, which allows a single-person household to meet and socialise with another household.
Parents are allowed to form a childcare bubble with another household for the purposes of informal childcare, where the child is 13 or under.
Can different households mix outdoors?
People are allowed to meet one person from another household socially and for exercise in outdoor public spaces, which does not include private gardens.
Can I attend funerals, weddings or religious services?
Up to 30 people will still be allowed to attend funerals, while stone settings and ash scatterings can continue with up to 15 guests.
Weddings and civil partnership ceremonies are not permitted except in “exceptional circumstances”. Places of worship must remain closed except for voluntary services, individual prayer and other exempt activities.
Can I travel in the UK or abroad for a holiday?
Most outbound international travel will be banned. There is no exemption for staying away from home for a holiday. This means people cannot travel internationally or within the UK, unless for work, education or other legally permitted exemptions.
Which businesses will close?
Everything except essential shops and education settings, which include nurseries, schools and universities, will close.
Entertainment venues will also have to close. Pubs, restaurants and indoor and outdoor leisure facilities will have to close their doors once more.
However, takeaway and delivery services will still be allowed, while construction and manufacturing will stay open.
Parents will still be able to access registered childcare and other childcare activities where reasonably necessary to enable parents to work. Some youth services may be able to continue, such as one-to-one youth work, but most youth clubs will need to close their doors.
Public services, such as jobcentres, courts, and civil registration offices will remain open.
There is no exemption for grassroots organised team sports. Elite sports will be allowed to continue behind closed doors as currently, including Premier League football matches.
The oversight in the app meant thousands of people were told they did not need to quarantine when they were in fact at risk of spreading coronavirus.
The problem was only discovered last week, when software engineers rewrote how the app decides who needs to isolate and discovered it had been relying on faulty maths since its launch in September. According to the Sunday Times, which reported on the flaw, a source said the fault meant that a “shockingly low” number of warnings were issued.
Despite claiming more than 19m downloads of the app, which is for use in England and Wales, the UK government has continually declined to reveal how many users have been advised to isolate. In Scotland and Northern Ireland, where similar apps have fewer users, more than 25,000 people have been warned of their possible exposure to the virus.
A Department for Health and Social Care (DHSC) spokesperson said the England and Wales version was “the only app in the world using the latest Google-Apple technology to better gauge distance to identify those most at risk, and is deemed ‘excellent’ by international standards.
“As previously published, we anticipate more app users who are at high risk of having caught the virus will receive a notification to self-isolate, and that will be to everyone’s long term benefit by reducing the chances of those with the virus passing it on to others.”
The root of the error, the Guardian has learned, was a decision to incorporate a measure of “infectiousness” into the app’s code. While the app was undergoing testing in the Isle of Wight, it used a simple metric that recommended isolation for anyone who had been in contact – closer than 2 metres – with a potentially infectious person for 15 minutes or more in a single day.
But shortly before the app was launched nationally, it was updated to account for the fact that people are most infectious shortly after their symptoms show. The maths was changed so that people outside that period of peak infectiousness counted for just two-fifths of the risk.
Since that meant the overall score was likely to be lower, the intention was to reduce the risk threshold correspondingly to ensure that someone of maximum infectiousness would need just three minutes of contact before they triggered an alert.
But that change never happened, and as a result, users were only told to isolate if they had spent 15 minutes close to a very infectious person, or nearly 40 minutes near someone who was pre-symptomatic but still thought to be shedding the virus.
The error was only discovered when a new version of the contact-tracing app, which can better account for exposures at mid-range (over a metre away) was created.
The unfeasibly high risk score also explained another problem plaguing the app: “ghost notifications” warning users that they may have been exposed to someone with Covid, but which never resulted in advice to isolate.
The app’s initial advice to users was that these notifications could be safely ignored, since they reflected a contact below the risk threshold; now that the NHS risk threshold is known to have been artificially low, one insider said, it is likely that the vast majority of those ghost notifications should in fact have been advice to self-isolate.
The new version of the app does away with them altogether: users will now only receive a notification if they are supposed to self-isolate.
“By removing these notifications, users can have the confidence that if they have a contact notification, they know it is from the app itself and based on the most accurate information available,” say Randeep Sidhu head of product for the test and trace app, and Gaby Appleton, the director.