The flu season appears to have arrived early, experts have said, as they urged people to get a flu jab.

Monitoring by the UK Health Security Agency (UKHSA) suggests cases of flu have risen across England, with more calls to NHS 111 and a slight rise in people seeking help from their GP for flu-like symptoms.

The UKHSA has urged everyone eligible to get a flu vaccine, saying Covid restrictions over the past two winters means people have little natural immunity.

The latest data suggests hospital and intensive admissions for the respiratory disease are rising quickest in children under five, though overall flu levels are still at a relatively low level, meaning it is difficult to predict how big the wave will be.

This year’s flu jab is a good match for the type of seasonal flu (H3N2) that is circulating this year.

In 2017/2018, the H3N2 flu strain led to a bad UK flu season, with around 20,000 deaths and 40,000 hospital admissions.

Dr Mary Ramsay, director of public health programmes at the UKHSA, said: “Our latest data shows early signs of the threat we expected to face from flu this season.

“We’re urging parents in particular not to be caught out as rates of hospitalisations and ICU admissions are currently rising fastest in children under five.

“This will be a concern for many parents and carers of young children, and we urge them to take up the offer of vaccination for eligible children as soon as possible.”

Around 33 million people in England are eligible for a free flu vaccine this year, including all primary-age and some secondary-age children, who will be offered the nasal spray.

Those eligible for the flu jab are: people aged 50 and over; those aged six months to 49 with a specified health condition; secondary school-aged children focusing on Years 7, 8 and 9 with any remaining vaccine offered to Years 10 and 11; primary school-aged children; pregnant women; those in care homes, frontline health and social care staff; carers and the household contacts of people with weakened immune systems.

These people can get a jab from their GP surgery or pharmacies offering an NHS vaccine service.

GPs are also inviting children aged two and three years old (as of August 31) for the nasal spray vaccine.

NHS medical director Stephen Powis said: “With growing cases of flu in the community already and currently over 10,000 people with Covid in hospital across England, the threat of a ‘twindemic’ that we have been concerned about is very clear.

“From falls services to 24/7 control centres, the NHS is working hard to prepare for a challenging winter and everyone who is eligible has the power to protect themselves from flu and Covid. It has never been easier to get your jabs so please come forward and book without delay.”