The move comes more than two years into the pandemic, and just days after free testing ended in England.
However, the NHS cautions that many of the new symptoms "are very similar" to those for colds and flu.
The original signs of a Covid infection that were recognised in the UK were:
- new continuous cough
- loss of sense of smell or taste
It was known from the early days of the pandemic that this trio was just the tip of the iceberg. The World Health Organization and other countries, including the US, have used a longer list of symptoms for some time.
However, there has been debate in the UK about precisely which symptoms should be recognised and qualify somebody for a Covid test.
A headache is a known symptom of Covid, but you might not want to test everybody with one, as there are so many other causes.
Fever, cough or loss of sense of smell or taste were settled on, because they were either present in most Covid cases or almost exclusively caused by the virus.
But now the list of symptoms includes a further nine:
- shortness of breath
- feeling tired or exhausted
- sore throat
- loss of appetite
- feeling sick or being sick
- blocked or runny nose
Covid infections are at a record level in the UK, with 4.9 million people (about one in 13 of us) testing positive for the virus. Free testing for most people in England ended last week.
The NHS says people should stay at home and avoid others only if you have Covid symptoms and a high temperature, or if your symptoms are so bad that you are not well enough to work.
Prof Tim Spector, from King's College London, has been campaigning for an expanded list of symptoms because of data from people tracking their symptoms in the Zoe Covid-19 app.
He said: "Main symptoms of coronavirus have finally changed after two years of lobbying... hurrah."