The 2025 H3N2 Flu Surge in England

The All You Need To Know series (AYNTK)

What’s happening – why it matters – and how to protect yourself

England is seeing a sharp rise in influenza cases this season, with H3N2 currently the dominant circulating strain. This subtype of influenza A tends to hit certain groups harder – particularly children, older adults, and those with long-term conditions – and is typically associated with higher hospitalisation rates compared with some other flu strains.

This blog outlines what is driving the current spike, what symptoms to look out for, how the flu vaccine offers protection, and what you can safely do at home to avoid complications such as dehydration and acute kidney injury (AKI). It also includes clear red-flag symptoms that mean you should seek medical help.

If you need a same-day review or you’re unsure whether your symptoms are normal, Bramley Pharmacy offers a private face-to-face clinic for assessment and advice.

What is happening with H3N2 in England right now

H3N2 is known to cause more severe seasonal outbreaks for a few reasons:

It mutates more rapidly, which can reduce existing population immunity.

Post-pandemic immunity gaps mean some age groups, especially younger children, have had less exposure to seasonal flu in recent years.

Winter co-circulation of other respiratory viruses (RSV, Covid-19) is increasing overall pressure on the NHS and amplifying symptoms for some patients.

Low vaccine uptake this season in some eligible groups has reduced the community buffer that normally slows transmission.

The combination of these factors is why NHS England has reported an unusually steep rise in admissions linked to influenza this winter.

For current NHS flu guidance:

NHS Flu Overview: https://www.nhs.uk/conditions/flu/

Does the flu vaccine protect against H3N2?

Yes – this year’s flu vaccines include coverage against H3N2, and although no vaccine offers 100% protection, evidence consistently shows that vaccination:

• Reduces the chances of catching flu
• Reduces severity and duration if you do catch it
• Lowers hospitalisation risk, especially in older people
• Reduces complications such as pneumonia and worsening of chronic conditions

Many of the hospitalised cases this season have been unvaccinated.

If you are eligible for the NHS flu jab, book as soon as possible.

If you are not eligible, Bramley Pharmacy offers private flu vaccinations.

Why some medications become unsafe during flu

One of the biggest risks during flu is dehydration. High temperatures, poor oral intake, sweating, vomiting, or diarrhoea all increase fluid loss.

Dehydration is a major driver of acute kidney injury (AKI), especially in patients taking medicines that rely on good kidney blood flow.

You should be especially cautious if you take:

• ACE inhibitors (ramipril, lisinopril, perindopril)
• ARBs (losartan, candesartan, valsartan)
• Diuretics / water tablets (furosemide, bendroflumethiazide, indapamide)
• NSAIDs (ibuprofen, naproxen, diclofenac) – avoid these if dehydrated
• Metformin – increased risk of lactic acidosis in dehydration
• SGLT2 inhibitors (dapagliflozin, empagliflozin) – higher risk of dehydration and ketoacidosis when unwell

During significant flu symptoms, follow the NHS Sick Day Rules guidance:

NHS Sick Day Rules (AKI prevention): https://www.nhs.uk/conditions/acute-kidney-injury/

If you are unsure whether to pause any medication, you can speak to Bramley Pharmacy for tailored advice.

Hydration: your best defence against complications

To reduce risk of AKI and hospitalisation:

• Drink little and often, aiming for pale-yellow urine.
• Avoid alcohol.
• Use oral rehydration salts if you are sweating, vomiting, or struggling to drink.
• Continue paracetamol for fever; avoid NSAIDs unless your clinician has said they are safe for you.
• Watch for signs of dehydration: dry mouth, dizziness, reduced urine, dark urine, or extreme fatigue.

Flu symptoms: what’s normal and what is not

Typical flu symptoms include:

• Sudden fever
• Muscle aches, chills
• Cough
• Headache
• Sore throat
• Exhaustion
• Loss of appetite

Symptoms usually peak between days 2–4 and gradually improve over a week, though cough and fatigue can last longer.

Red flags: when to seek medical help

Call NHS 111 or seek urgent care if you experience:

• Shortness of breath, chest pain, or difficulty breathing
• Severe dehydration (very little urine, dizziness, confusion)
• A fever that lasts more than 4–5 days or returns after improving
• Symptoms of pneumonia (persistent high fever, worsening cough, breathlessness)
• Severe weakness, unable to stand or drink properly
• A rash that does not fade with pressure
• Very young children who are unusually sleepy, floppy, refusing fluids, or having breathing difficulty
• Older adults who appear confused or drowsy

Emergency symptoms (999):

Blue lips, severe breathing difficulty, chest pain, seizures, or sudden collapse.

How to reduce spread and protect others

• Stay home until your fever settles
• Keep good hand hygiene
• Wear a mask if you must leave the house
• Use tissues and dispose safely
• Keep rooms ventilated
• Avoid visiting vulnerable family members until fully recovered

Need help? Bramley Pharmacy can offer same-day support

If you are unsure whether your symptoms are normal or need clinical assessment, our private face-to-face clinic can:

• Assess your symptoms
• Check hydration status and vitals
• Advise on medication safety during illness
• Prescribe treatment when appropriate
• Direct you to NHS services if needed

To book

Call  0208 840 4464