The flu poses a significant challenge to public health every year, particularly for the elderly, children, and people with chronic conditions. According to the latest data from the European Centre for Disease Prevention and Control (ECDC), vaccination coverage among adults over 65 in EU/EEA countries averaged 47% in the 2024–25 season, with values ranging from 5% to 76% across different countries. Only a few countries (Denmark, Ireland, Portugal and Sweden) reached the recommended minimum target of 75%, highlighting the need to increase participation in vaccination programmes.
In Italy, the situation is not encouraging. In the 2024–25 season, only 52.5% of people over 65 were vaccinated against the flu, while general population coverage was around 19.6%, well below the targets recommended by the National Vaccination Prevention Plan. These figures emphasise the importance of preventing flu through vaccination, as this reduces the risk of becoming unwell, mitigates symptoms and complications, and decreases hospitalisations and deaths, particularly among vulnerable groups such as the elderly, people with chronic conditions, and pregnant women. Seasonal vaccination remains a vital strategy for safeguarding both individual and public health.
To find out more, we interviewed Professor Maria Rosaria Gualano, a lecturer in General and Applied Hygiene at UniCamillus University.
Types of flu vaccine and coverage
Should we talk about the vaccine, or is it more correct to say ‘the vaccines’? Today, several types of flu vaccine are available, designed to meet the needs of different age groups and clinical conditions. Standard quadrivalent vaccines are mainly used for adults and protect against four different viral strains: two strains of influenza A (usually H1N1 and H3N2) and two strains of influenza B. These vaccines contain inactivated viruses and are therefore unable to cause the disease. The quadrivalent formulation is now the most widely used because it provides broader protection than the trivalent versions of the past, increasing the likelihood that the vaccine will remain effective even if circulating viruses change during the season.
Specific vaccines are available for older people, whose immune response is naturally weaker due to immunosenescence (the ageing of the immune system). These vaccines help enhance the effectiveness of protection. Adjuvanted vaccines contain a substance called an adjuvant (such as MF59) that stimulates the immune response and increases antibody production. There are also high-dose vaccines that contain a greater quantity of antigen—the part of the virus that the immune system must recognise. Both formulations aim to compensate for the lower immune system reactivity typical of advanced age, ensuring more robust protection against complications and hospitalisations.
Dedicated solutions for children take into account different age groups and the particular reactivity of their immune systems. Older children can receive a ‘live-attenuated’ nasal spray vaccine containing viruses that have been rendered harmless but are still able to stimulate a natural immune response. It is administered directly into the nose—the very place where the flu virus enters the body—allowing rapid defences to be activated. Inactivated vaccines are available in paediatric formulations for younger children or children who cannot receive the spray vaccine. These are identical in principle to adult vaccines, but the dosage is calibrated according to age and immune status. In some cases, especially if the child is being vaccinated for the first time, a second booster dose may be recommended to provide stronger protection.
“The duration of protection is generally about six months, which is sufficient to cover the entire flu season”, says Gualano. “Even if the flu is contracted, vaccination helps to significantly reduce the severity of the disease and the risk of complications requiring hospitalisation”.
The best time to get vaccinated
The timing of seasonal vaccination is important to ensure its effectiveness. According to Professor Gualano, the ideal period is between October and the end of November, allowing the body to develop adequate protection before the flu season peaks, usually between December and early February. “However, it is still possible to get vaccinated up until December without compromising protection,” she adds. This also enables those who decide later to benefit from vaccination, particularly individuals in the most vulnerable categories. So there is still time!
Is the vaccine free? Yes, for certain groups
In Italy, the flu vaccine is free for certain at-risk groups. These include people over 60, individuals with underlying health conditions, pregnant women, children aged six months to six years, and healthcare workers. “Providing free vaccination for these groups is a way to ensure widespread protection and reduce the impact of influenza on public health”, the expert notes. However, some regions also extend the offer to other segments of the population.
Why is the flu vaccine so highly recommended during pregnancy? Vaccination during pregnancy offers benefits to both the mother and the unborn child. It protects the woman from the risk of developing serious influenza-related complications and, thanks to antibodies passing through the placenta, protects the newborn in the first months of life, when they cannot yet be vaccinated. Clinical and observational studies show that maternal vaccination can reduce hospitalisations for influenza in infants and lower the likelihood of preterm birth or low birth weight in high-risk contexts.
Side effects and contraindications before and after vaccination
Professor Gualano confirms that there are no particular precautions to take before vaccination and that no specific preparation is necessary. After the injection, no extended observation period beyond the usual 15–30 minutes required to monitor for immediate allergic reactions is necessary, except in special circumstances.
“In the hours following vaccination, it is advisable to avoid strenuous activity and get some rest, especially if mild symptoms such as low-grade fever, fatigue, or a general feeling of malaise appear. These are considered normal and temporary effects. Staying well hydrated can help alleviate these symptoms”, notes Gualano. “If you experience pain at the injection site, slight swelling, or, more rarely, fever and headache, you can take analgesics or antipyretics as needed, but always follow your doctor’s instructions”. The professor points out that these symptoms tend to resolve spontaneously within a short time.
Is it possible to receive multiple vaccines at the same time? “Co-administration of vaccines (e.g. two injections given at different sites, such as the right and left arms) is often recommended for organisational reasons, and in most cases does not present any incompatibility”, explains Professor Gualano.
Are there any contraindications to the flu vaccine? “The most serious reactions, such as anaphylaxis, are extremely rare, occurring in approximately one case per million doses”, Gualano notes. “In general, vaccination is considered a safe way to protect the health of individuals and communities”.
However, as the expert explains, “vaccination should not be administered in cases of previous severe allergic reactions or acute infections with high fever”. Special attention is also required for people undergoing immunosuppressive therapy: vaccination is not contraindicated, but its effectiveness may be reduced. In these situations, it is advisable to consult your doctor to determine the most appropriate timing.
Prevention is not just about vaccines. The role of lifestyle
However, one message must be clear: prevention goes beyond the flu vaccine and involves simple, everyday behaviours.
“The experience of the pandemic has taught us a lot about how to protect ourselves from respiratory infections”, notes Gualano. “Frequent handwashing, ventilating rooms, and avoiding close contact with sick people are fundamental strategies”.
As international recommendations also point out, small habits can make a big difference, especially during periods when viruses and bacteria circulate more intensely. It is not just a matter of avoiding infection; it is also a question of responsibility towards others.
“If you are symptomatic, it is important to reduce contact and adopt appropriate behaviour, such as covering your nose and mouth when coughing or sneezing”, adds Gualano. “Masks remain an effective tool for limiting transmission in crowded settings during an epidemic”.
So, while vaccination remains the cornerstone, prevention is a mosaic made up of many important pieces. Each one can contribute to making the flu season safer for everyone.