Children and adults across England are receiving strong
protection from this year's flu vaccine, despite the emergence of
a new subclade driving an unusually early flu season.
New data published today
as a pre-print by the UK Health Security Agency (UKHSA) shows the
2025/26 vaccine is currently 70 to 75% effective at preventing
hospital attendance in children aged 2 to 17 years and 30 to 40%
effective in adults.
The early findings confirm the vaccine provides important
protection even though a drifted influenza A(H3N2) strain (also
now known as subclade K) currently dominates cases in England, so
the protection levels observed in children are particularly
encouraging this year. Flu vaccine effectiveness varies from
season to season but is typically between 30 to 60%, with higher
vaccine effectiveness typically seen in younger age groups.
High effectiveness in younger age groups may also provide
indirect protection to other groups through reduced transmission.
UKHSA assesses vaccine effectiveness by studying whether people
who have been vaccinated are less likely to attend or be admitted
to hospital with influenza.
The UK flu programme uses technologically advanced vaccines
optimised for each patient group. The observed levels of
effectiveness seen in this study are similar to typical flu
seasons and this demonstrates that enhanced vaccines can provide
strong protection, even when the virus has evolved.
Flu activity has risen unusually early this season, with
increases first seen in teenagers and young adults, followed by
younger children. Almost all cases have been influenza A, with
84% identified as the H3N2 subtype where testing was available.
Dr Jamie Lopez Bernal, Consultant Epidemiologist for Immunisation
at UKHSA said:
These results provide reassuring evidence that this season's flu
vaccines currently offer important protection to children and
adults, despite concerns about the new subclade. The high vaccine
effectiveness in children strengthens the case for ensuring all
eligible young people get vaccinated. When more children are
protected, it helps stop the spread of flu to others around them.
Importantly, whatever strains do circulate here this winter, we
can be confident that the vaccine will still help to protect
those most vulnerable from developing serious illness and being
hospitalised. We strongly encourage all those eligible to get
vaccinated against flu as soon as possible – it remains our best
defence against serious illness.
Good respiratory hygiene is also key in preventing the
transmission of flu and other viruses. Anyone with symptoms -
including high temperature, cough, and feeling tired or achy –
should minimise contact with others, especially those who are
vulnerable. Wash hands regularly and ensure indoor spaces are
well ventilated, and if you need to go out with symptoms,
consider wearing a face covering.
Vaccination remains the most effective way to protect against
flu. Eligible groups include children aged 2 to 17, adults aged
65 and over, pregnant women, and those with certain health
conditions. Book your
appointment today.
For more information on how our vaccines protect against
different flu types visit our latest blog
post.
