LONDON: Getting an annual flu shot is the single best way to prevent influenza and its complications, health experts say. The vaccine reduces the risk of infection. It also cuts the chances of severe illness, hospital admission and death, according to public health authorities.
Influenza is a viral infection of the nose, throat and lungs. Most people recover without treatment. But the disease can cause serious complications in older adults, young children, pregnant people and those with chronic illnesses.
The Centers for Disease Control and Prevention (CDC) and other health bodies advise yearly vaccination for almost everyone aged six months and above.
This year’s seasonal vaccines typically protect against three strains researchers expect to circulate. Manufacturers take months to produce vaccines, so shipments in the United States usually begin in late summer.
Once given, a vaccine takes about two weeks to provide full protection. For that reason, health officials commonly recommend vaccination in September or October for people in the Northern Hemisphere, though benefits persist if the jab is given later in the season.
Why you need a shot every year
Flu viruses change quickly. New vaccines are developed annually to match the strains likely to spread.
Immunity from vaccination also wanes over time. For these reasons, an annual flu shot is advised even for people who were vaccinated the previous year, the CDC says.
Vaccine effectiveness varies by season and by strain. Reviews of data since 2009 show protection ranging from roughly 22% to 56%.
Even when effectiveness is modest, vaccines still prevent many illnesses and reduce the number of severe cases and deaths.
Who should be vaccinated?
Annual flu vaccines are available in the United States for people aged six months and older. They are recommended for everyone who does not have a medical reason to avoid them.
Special formulations — such as high-dose or adjuvanted vaccines — are offered to people aged 65 and older and are intended to boost the immune response in that age group. Children between six months and eight years may need two doses the first time they are vaccinated.
People with chronic conditions, weakened immune systems, very high body mass index, or neurological conditions are at greater risk of complications and should take particular care to be vaccinated.
Pregnant people also benefit from vaccination; if given later in pregnancy, the shot also helps protect newborns.
Types of vaccine and common concerns
Flu vaccines are available as injections, jet injections and a nasal spray. The nasal spray is approved for people aged two to 49, but it is not suitable for some groups, including pregnant people, those with severe asthma, or people with certain immune problems.
The vaccine cannot give you the flu, public health experts emphasise. Mild, short-lived symptoms such as muscle aches, low-grade fever or headache can occur as the immune system responds to the vaccine.
Another reason people might fall ill after vaccination is exposure to the virus shortly before or within the two-week window before immunity develops. Also, other respiratory viruses can cause flu-like symptoms.
What to eat and drink before a flu shot
Medical News Today asked diet and nutrition specialists for practical advice on food and drink around vaccination.
Michelle Routhenstein, MS, RD, CDCES, CDN, a preventive cardiology dietitian at EntirelyNourished, said hydration and a light, balanced snack can help prevent dizziness and fainting.
“Drinking water or herbal tea supports circulation and maintains blood volume,” she said. “A snack containing protein and complex carbohydrates, such as a banana with nut butter, stabilises blood sugar and reduces the risk of feeling weak.”
Şebnem Ünlüişler, MSc, a genetic engineer and Chief Longevity Officer at the London Regenerative Institute, agreed that stabilising blood sugar and staying hydrated are simple preventive steps. She recommended yogurt with oats or wholegrain toast as suitable pre-vaccine snacks.
What to eat and drink after a flu shot
Post-vaccination, a balanced meal can support recovery and the immune response, nutritionists say. Elena Rolt, MSc, DipION, IFMCP, a nutritional therapist at Health.Miro, noted that the immune system mounts an inflammatory response to process the vaccine.
“Protein is crucial for antibody and immune cell synthesis,” she said. Rolt recommended meals that combine protein, fibre and vitamin C — for example, a chicken broth with vegetables and a berry-based drink or tea — to help moderate inflammation and support immune function.
Ünlüişler added that foods rich in omega-3 fatty acids and spices such as turmeric may help moderate inflammation without blunting the immune response.
All three experts stressed that no specific food or drink changes the vaccine’s efficacy, but good nutrition and hydration can make the experience more comfortable.
Simple precautions to reduce flu risk
Alongside vaccination, public-health measures lower the chance of infection. Regular hand-washing, covering coughs and sneezes, avoiding touching the face and staying away from crowded places during peak season all reduce transmission.
If you are sick, stay home until symptoms ease and you have been fever-free for 24 hours without fever-reducing medicines.
Flu vaccines are widely available from healthcare providers, pharmacies, clinics and workplace or school programmes.
In much of the Northern Hemisphere, autumn is the time to get immunised. Consult local health authorities or your healthcare professional about timing and the best vaccine for your age and health status.
Public-health authorities say the flu shot remains the best defence against influenza. It reduces the risk of infection and the severity of disease.
