Just over a third of eligible two- and three-year-olds in England have received a flu vaccination this season, according to NHS England (NHSE) data.
The latest figures reveal that 2.3 million vaccines have been administered to eligible children, including 400,000 toddlers aged two and three, representing only 33.4% of that group.
NHSE has expanded access by offering the vaccine at nearly 4,000 local pharmacies in a one-season trial, as well as in supermarkets and on high streets.
Parents are urged to submit vaccination consent forms to schools or to book appointments for their two- to three-year-olds to protect them before the Christmas holidays.
According to the UK Health Security Agency, "this year’s flu season is off to an ‘unusually early start’."
NHSE warned this could lead to a "long and drawn-out winter" for the health service, with cases currently three times higher than at the same time last year.
NHS England has increased flu vaccine availability for toddlers, yet uptake remains low amid warnings of an early, intense flu season.