A record-breaking number of NHS staff were off sick during the height of the Covid-19 crisis, official figures show.
NHS Digital statistics released today revealed 6.2 per cent of health service staff in England were absent on any given day in April, on average.
At that point hospitals were battling an extraordinary influx of Covid-19 patients and up to 1,000 Britons were dying to the disease every day.
It marks the highest monthly sickness absent rates since modern records began, stretching back more than a decade to 2009.
One ambulance trust in the South East of England reported 12.8 per cent of its staff took sick leave during that month, the equivalent of around one in eight workers.
More than one in 20 (5.4 per cent) of NHS staff were off ill in March of this year, when the virus began to spiral out of control and spread exponentially.
The last time NHS staff absence rates were as high was in January 2018, when 5.03 per cent of staff took ill following a bad outbreak of Aussie flu.
Frontline workers were disproportionately struck down by Covid-19 at the height of the pandemic, with some estimates suggesting half could have been infected.
Others were forced to take sick leave and quarantine because they were suspected of having the illness or came into contact with someone who later tested positive.
NHS workers were not routinely tested at the time and many struggled to get their hands on protective gear, with some resorting to making their own.
The NHS Digital report showed trusts in London — formerly the UK’s coronavirus epicentre — had more staff off sick than anywhere else.
Almost one in 13 healthcare workers (7.2 per cent) in the capital were off in April, compared to 4.5 per cent in the South West of England, the lowest in the country.
The North West had the second highest number of absences, at 6.9 per cent, followed by the South East (6.5 per cent) and the East (6.3 per cent).
The Midlands (6.1 per cent) and the North East and Yorkshire (5.9 per cent) reported a similar number of absentees.
Ambulance trusts had the highest sickness absence rate at 7.3 per cent followed by acute trusts, which provide services such as A&E departments, at 6.5 per cent.
The South Central Ambulance Service NHS Foundation Trust recorded the highest number of staff off sick in April, at 12.8 per cent.
The finding is curious because the South East of England largely avoided a major crises, but many staff were being told to go off as a precaution.
Hillingdon Hospitals Trust in the West London borough saw 11.4 per cent of its workers off on sick leave during that month.
West Hertfordshire Hospitals NHS Trust saw 11.3 per cent of its staff absent from the three hospitals it encompasses in the East of England.
Epsom and St Helier University Hospitals NHS Trust in London and Southport and Ormskirk Hospital NHS Trust in the North West each had about one in 10 off sick on any given day.
Healthcare assistants were the group most likely to be off ill during April, with 8.2 per cent of them off at any one time.
They were followed by hospital cleaners and cooks (8.1 per cent), nurses (7.4 per cent) and ambulance staff (7.1 per cent).
One of the UK’s top medics, Sir Paul Nurse, told MPs last month that almost half of all NHS staff have had Covid.
Sir Paul, director of the renowned research centre, the Francis Crick Institute, said ‘up to 45 per cent’ of healthcare workers were infected in April.
But a lack of testing meant most cases went under the radar because the majority of workers were asymptomatic.
He told the Health and Social Care Committee: ‘At the height of the pandemic, our own research, and of course that only backs up what’s been done elsewhere, is that up to 45 per cent of healthcare workers were infected.
‘And they were infecting their colleagues, they were infecting patients, yet they weren’t been tested systematically.’
Professor Sir John Bell, a medicine expert at the University of Oxford, told the same committee that NHS trusts avoided testing staff for the virus en masse because they was afraid thousands would have to go off sick and leave swamped hospitals without workers.
Sir John said: ‘As time went on, there still wasn’t a real push to do healthcare workers and indeed, all patients in the hospital. And it sort of went on, and on, and on.
‘And indeed there was a suspicion, which I think is probably correct, that NHS institutions and the NHS were avoiding testing their hospital workers because they were afraid they would find [high levels of infection] and they would have to send everyone home, and as a result not have a workforce.
‘That in my view is not an ethical approach to the problem. You can’t not test people because you’re worried about a human resources issue. But I think that was a pretty central issue in that failure to test hospitals.’
It comes after 10,000 healthcare workers have signed up to take part in a Government study which aims to solve the mystery of whether people can get reinfected with Covid-19.
Public Health England researchers will follow volunteers for at least a year, regularly swabbing them for the virus and taking blood samples to search for antibodies.
Participants are a mix of frontline NHS staff of all ages from hospitals dotted across England, many of whom will have already had coronavirus and recovered.
Recruitment in Scotland, Wales and Northern Ireland will begin in the coming weeks and PHE told MailOnline today it hopes to eventually recruit 100,000 volunteers.
Preliminary results from the study, known as SIREN (SARS-CoV-2 Immunity and REinfection EvaluatioN) are expected before the winter — when experts fear Britain will be hit by a second wave.
There is currently no scientific consensus about how long natural immunity against Covid-19 lasts because the disease hasn’t been around long enough.
The European Centre for Disease Control estimates survivors are protected for up to a year, depending on their age and how good their immune system is. This is in line with common colds and seasonal flu, which is why people are urged to get a new influenza jab every year.
But the Centre for Disease Control (CDC) in the US says its research indicates that immunity lasts just three months, the same as other human coronaviruses.
Scientists need to iron out the burning question of Covid immunity to inform public health policies — like who is safe to go back to work and which vulnerable groups must continue to shield.
It also would mean that any protection from a vaccine may not be very long lasting and a jab may need to be reformulated every year.