The UK Health Security Agency (UKHSA) is encouraging people to consider wearing face masks, among other precautions, as a number of winter viruses are spreading across the country.

Health chiefs are particularly concerned about the levels of influenza, flu, after a mutation of the virus kick-started flu season more than a month early this year.

“We haven’t seen a virus like this for a while, these dynamics are unusual,” said Prof Nicola Lewis, the director of the World Influenza Centre at the Francis Crick Institute. She added: “It does concern me, absolutely. “I’m not panicking, but I am worried.”

In a new post on X, formerly Twitter, the UKHSA is urging people to “help stop common infections like flu from spreading” by taking a number of steps.

These are washing hands regularly, opening windows when socialising inside, and catching coughs and sneezes in a tissue.

If you feel unwell, UKHSA adds, you should stay at home if you can, and wear a mask if you need to go out.

According to the latest data, positive flu rates increased slightly in the seven days to Tuesday, November 25 – rising from 10.7% in the previous week to 11.6%.

Health chiefs said positivity rates were highest in children aged 5-14. 

Flu symptoms often come on quickly, and can include a sudden high temperature, body aches, a sore throat, a dry cough, fatigue, headaches, diarrhoea or stomach pain, feeling or being sick, loss of appetite and difficulty sleeping.

Children with flu may also suffer from earache and seem less active.