Figures from the Office for National Statistics (ONS) show there has been a marked increase in the number of people with self-reported long Covid that has lasted for at least a year.

Here, the PA news agency answers the key questions about the condition.

– What is long Covid?

Long Covid, also known as post-Covid syndrome, is used to describe the effects of the virus that continue for weeks or months beyond the initial illness.

– What are the symptoms?

There are a wide range of common long Covid symptoms including fatigue, shortness of breath, chest pain or tightness, problems with memory and concentration, insomnia, dizziness, pins and needles, joint pain, depression and anxiety, tinnitus, earaches, feeling sick, diarrhoea, stomach aches, loss of appetite, a high temperature, cough, headaches, sore throat, changes to sense of smell or taste or skin rashes.

– What are the other effects?

In a recent study, 79.5% of people living with long Covid reported problems with their usual activities, more than half (56.2%) reported problems with their mobility.

– How many people are suffering and for how long?

An estimated 1.0 million people in private households in the UK reported experiencing long Covid in the four weeks to May 2, according to the latest figures from the ONS.

Of these people, an estimated 869,000 first had Covid-19 – or suspected they had Covid-19 – at least 12 weeks previously, while 376,000 first had the virus or suspected they had the virus at least one year ago.

This is an increase on previous figures covering the four weeks to March 6 2021, which suggested that 70,000 people in private households in the UK had experienced symptoms of long Covid for at least 12 months.

– Who is affected?

People of any age are thought to be affected, with children as young as four and pensioners over the age of 85 reporting ongoing symptoms.

The ONS has found that prevalence of self-reported long Covid was greatest in people aged 35 to 69, females, those living in the most deprived areas, those working in health or social care, and those with another activity-limiting health condition or disability.

– What have health experts said?

Scientists from the UK’s National Institute for Health Research, who reviewed the available evidence of the symptoms in October 2020, believe ongoing Covid may not be one illness but at least four different syndromes.

These have been broadly categorised as: post-intensive care syndrome, post-viral fatigue syndrome, permanent organ damage and long-term Covid syndrome.

– What treatment is available?

Outgoing NHS boss, Sir Simon Stevens, has said there will be a long Covid clinic in each local health area in England.

People are urged to contact their GP if they are worried about symptoms four weeks or more after having Covid-19.

The NHS also has a Your Covid Recovery support tool, which offers advice and is available at https://www.yourcovidrecovery.nhs.uk/