Do you need a flu shot? Who cares?

Influenza is not synonymous with a mild seasonal cold, but a distinct viral infection with a significant burden on healthcare systems. The WHO clearly states that vaccination remains the best way to prevent influenza, and safe and effective vaccines have been used for over 60 years. This is important because influenza is often underestimated in everyday perception, despite being responsible for a significant proportion of severe complications and hospitalizations each year. [1]

The current approach in a number of countries is based on annual vaccination of all people aged 6 months and older, unless contraindicated. The CDC maintains this recommendation for the 2025-2026 season, and the ECDC confirms that countries in the European Union and the European Economic Area continue to recommend vaccination for at least key risk groups, while expanding recommendations for children and adolescents. This differs markedly from the outdated idea that vaccination is only necessary for a small number of people. [2]

The reason for annual vaccination is simple: influenza viruses are constantly changing, and immune protection from previous vaccinations weakens over time. The CDC and WHO emphasize that new seasonal vaccines are updated annually to account for expected circulating strains, and protection develops approximately two weeks after administration. Therefore, it's not a "one-and-done" vaccination, but rather seasonal protection that needs to be renewed. [3]

Even in seasons when the match between vaccine and circulating strains is less than perfect, the effect is not negligible. The CDC explicitly states that even with an imperfect match, the vaccine can provide at least partial protection, and the WHO specifically notes that in older people, it may be less effective against infection, but still reduces the severity of the disease, the risk of complications, and death. This is one of the most important clinical distinctions between a serious medical recommendation and the common myth that "if it doesn't protect 100%, it's useless." [4]

Recent data only confirm the practical importance of vaccination. The CDC estimates that in the 2024-2025 flu season, influenza was associated with 51 million illnesses, 710,000 hospitalizations, and 45,000 deaths, while vaccination prevented 11 million illnesses, 180,000 hospitalizations, and 12,000 deaths. As of the week ending February 21, 2026, 79 influenza-associated childhood deaths had been reported in the United States, and of the children who died for whom vaccination was indicated and whose status was known, approximately 90% were not fully vaccinated. [5]

What does the flu shot provide?	What she doesn't promise
Reduces the risk of disease	Does not guarantee 100% protection against any case of flu
Reduces the risk of hospitalization	Does not protect against all colds and other viruses
Reduces the risk of severe disease and death	Does not work immediately on the day of injection
It can soften the course of the disease if infection does occur.	Does not replace hygiene, masks during illness, and early treatment in risk groups.

The table is compiled from current CDC and WHO materials on the benefits and limitations of seasonal vaccination. [6]

For whom is vaccination especially important?

Although annual vaccination is widely recommended, there are groups for whom the question is not "preferred" but rather "especially important not to miss a season." The WHO lists healthcare workers, the elderly, pregnant women, and people with chronic diseases as priority groups. The ECDC reports that countries in the European Union and the European Economic Area continue to recommend vaccination for these key target groups, and recommendations for children and adolescents have expanded in recent seasons. [7]

The first major group is children. The CDC recommends annual vaccination starting at 6 months, but younger age itself increases the risk of complications, especially in children under 5 years of age and especially under 2 years of age. Infants under 6 months of age are not yet eligible for vaccination, so protection is built around vaccination of the pregnant woman, parents, other family members, and caregivers. [8]

The second key group is pregnant women. Current recommendations are clear: the inactivated vaccine can be administered in any trimester, and the vaccination itself reduces the risk of disease in the mother and helps protect the baby in the first months of life, when they are still too young to be vaccinated themselves. The CDC specifically emphasizes that vaccination in July or August can be considered for women in the third trimester, if the vaccine is already available, to enhance protection for the newborn after birth. [9]

The third major group is the elderly. With age, the immune response to infection and vaccination changes, and the risk of severe illness, hospitalization, and death increases. The CDC indicates that people 65 and older account for 70-85% of influenza-related deaths and 50-70% of hospitalizations, so it is especially important for this group not just to get any vaccine, but, whenever possible, to use the vaccines considered preferable for this age group. [10]

The fourth group is people with chronic medical conditions. The CDC notes that in recent flu seasons, 9 out of 10 people hospitalized with the flu had at least one underlying condition. The NHS lists asthma, chronic obstructive pulmonary disease, heart disease, kidney disease, liver disease, diabetes, and some neurological conditions as direct grounds for annual vaccination. [11]

The fifth group includes people with immunodeficiency, cancer patients, residents of care homes and long-term care facilities, and those living near or caring for severely immunocompromised people. The NHS specifically includes in its recommendations residents of care homes, primary carers of elderly and disabled people, and those living with someone with a weakened immune system. Frontline health and social care workers are also an important target group, as vaccination protects not only themselves but also the vulnerable patients with whom they come into contact. [12]

Group	Why is it especially important?
Children from 6 months, especially up to 5 years	There is a higher risk of complications; in very young children the disease can quickly worsen.
Pregnant women	Higher risk of severe course of the disease for the mother, plus protection of the child in the first months of life
People 65 years and older	Higher risk of hospitalization and death
People with asthma, heart failure, diabetes, kidney disease, liver disease, nervous system disease	Influenza often worsens the underlying disease.
Immunocompromised patients	Higher risk of severe infection
Residents of nursing homes	High risk of outbreaks and complications
Healthcare workers and caregivers	They can infect vulnerable patients and their loved ones.

The table is based on current recommendations from the CDC, NHS, WHO and ECDC on high-risk groups.[13]

When is the best time to get vaccinated and what vaccines are currently in use?

For most people who need one seasonal shot, September and October remain the optimal time. The CDC specifically states that September or October is generally a good time for pregnant women to get vaccinated, and for most other seasonal recipients, this is also the baseline window because it allows them to already have developed protection against the main flu wave. However, getting vaccinated too early in July and August is generally not considered the best option for most adults, unless there are special circumstances. [14]

There are exceptions. For children aged 6 months to 8 years who require two doses this season, the first dose is given as early as possible to complete the schedule before active virus circulation begins. The CDC indicates that two doses are required for children who are being vaccinated for the first time, have previously received only one dose, or if their previous vaccination history is unknown. [15]

For the 2025-2026 flu season, influenza vaccines in the US are trivalent, meaning they protect against three viral components: two influenza A variants and one B/Victoria lineage variant. This is an important update compared to previous texts, which often described older formulations or created the impression that all vaccines were identical. In practice, inactivated vaccines, recombinant vaccines, and a live-attenuated intranasal vaccine exist. [16]

For people 65 and older, the CDC recommends three preferred options: the high-dose trivalent vaccine, the recombinant trivalent vaccine, and the adjuvanted trivalent vaccine. These vaccines are considered potentially more effective in older adults, whose normal immune response may be weaker. However, if they are not available at the time of presentation, there is no need to delay protection; any other age-appropriate vaccine should be used. [17]

A nasal live-attenuated vaccine exists, but it is not suitable for everyone. It is approved for use in people aged 2-49 years, but has certain restrictions: for example, it is not used during pregnancy, in immunocompromised patients, or in children aged 2-4 years with asthma or a recent history of wheezing. Therefore, the inactivated injectable vaccine remains the universally effective option for most vulnerable groups. [18]

Situation	Usually suitable
Most adults and children 6 months and older	Inactivated vaccine
Pregnancy in any trimester	Inactivated vaccine
Age 65 years and older	High-dose, adjuvanted, or recombinant vaccines are preferred.
A child aged 6 months to 8 years is vaccinated for the first time.	2 doses may be needed
A healthy person 2-49 years old without a number of restrictions	A live nasal vaccine is possible if there are no contraindications

The table is based on current CDC recommendations for the 2025-2026 season. [19]

Who really shouldn't get vaccinated, and who should simply postpone it or choose a different type of vaccine

There are not as many absolute contraindications to influenza vaccination as is commonly believed. For inactivated and recombinant vaccines, the main real contraindication remains a severe allergic reaction to a previous dose of the corresponding vaccine or to a specific component of the vaccine other than egg. Furthermore, in the presence of a moderate or severe acute illness, vaccination is usually postponed until recovery. [20]

Guillain-Barré syndrome requires special caution within 6 weeks of a previous flu vaccination. CDC recommendations do not present this as a blanket ban for everyone, but as a situation requiring an individualized risk-benefit discussion. Similarly, a moderate or severe acute illness is usually a reason to wait, rather than permanently forgo vaccination. Vaccination is usually safe for mild colds. [21]

Egg allergy is no longer considered a typical reason to refuse the flu vaccine. The CDC explicitly states that people with egg allergies can receive any flu vaccine that is appropriate for their age and health status, and that additional precautions beyond the usual ones are no longer required simply because of the egg allergy itself. This is one of the most significant updates compared to the old patient information. [22]

Pregnancy is also not a contraindication for the inactivated vaccine. In fact, the CDC recommends vaccination in any trimester. The restriction applies specifically to the live nasal vaccine, which is contraindicated during pregnancy. Vaccination is also acceptable after childbirth and during breastfeeding, and antibodies developed in the mother partially help protect the baby through breast milk. [23]

The most important practical amendment to the old article is this: asthma, heart failure, chronic kidney disease, diabetes, neurological diseases, and many other chronic conditions are not "who shouldn't get it," but "who especially needs it." In the case of the live nasal vaccine, some of these conditions may be a reason to choose a different form of the vaccine, but this doesn't mean refusing vaccination altogether. A mistake here is especially dangerous because it can deprive those who need it most of protection. [24]

A common statement	What do the current guidelines say?
Pregnant women should not be vaccinated during the first trimester.	The inactivated vaccine is acceptable in any trimester.
If you are allergic to eggs, vaccination is prohibited.	Any suitable vaccine can be used.
Asthma and heart failure are contraindications	These are high-risk groups for whom the vaccine is especially important.
Any cold cancels vaccination	For mild illnesses, vaccination is usually possible.
If you had a severe reaction to a previous vaccination, you can simply get any other one without discussion.	An individual assessment is required based on the type of vaccine and its components.

The table reflects the current positions of the CDC and NHS on contraindications and risk groups. [25]

What does the vaccine actually give and what shouldn't you expect from it?

The flu vaccine does not protect against all winter respiratory infections. It specifically targets influenza viruses, not rhinoviruses, adenoviruses, coronaviruses, or other pathogens that can also cause fever, sore throat, and cough. Therefore, if a person develops a cold-like illness after vaccination, this does not automatically mean the vaccine failed. [26]

The vaccine also does not cause influenza. The CDC, in its official advisory, explicitly states that the inactivated or recombinant vaccine cannot cause influenza, and the protective effect develops in approximately 2 weeks. If a person becomes ill shortly after vaccination, it is usually due to either infection before the immune response has developed, another respiratory infection, or the circulation of a strain against which protection was incomplete. [27]

Expected adverse reactions are generally mild and short-lived. The most common are soreness, redness, and swelling at the injection site, mild fever, muscle aches, and headache. The CDC also notes a very small increased risk of Guillain-Barré syndrome after the inactivated vaccine, while severe allergic reactions remain rare. Therefore, the safety conversation should be honest: the risk is not zero, but serious complications are rare, and the benefits for at-risk groups usually significantly outweigh the risk. [28]

It's also important that vaccination doesn't replace other preventative measures. The WHO, CDC, and NHS emphasize the role of hand hygiene, respiratory etiquette, isolation during illness, and protecting at-risk individuals. For those at high risk of complications, the appearance of flu symptoms isn't a reason to "just wait it out," but rather a reason to promptly contact a doctor, as early initiation of antiviral therapy can be particularly beneficial. [29]

If we're looking for the most practical conclusion, it's this: For most people over 6 months of age, the seasonal flu vaccine is a reasonable annual preventative measure. For pregnant women, young children, the elderly, people with chronic illnesses, people with immunodeficiency, residents of nursing homes, healthcare workers, and close contacts of vulnerable people, it's not just a "good idea" but one of the most important seasonal measures for reducing the risk of severe illness. [30]

After vaccination it is possible	Usually does not require alarm	Requires contact with a doctor
Pain at the injection site	Yes	No, if it passes quickly
Slight fever, aches and pains, headache	Yes	If they are severe or prolonged
Fainting immediately after injection	Sometimes possible as a reaction to the procedure	Yes, if the condition is not restored
Shortness of breath, facial swelling, generalized urticaria	No	Yes, urgently
Flu symptoms after a few weeks	Not necessarily related to the vaccine itself	Yes, especially in people from risk groups

The table is based on the official CDC information on risks and expected reactions after vaccination. [31]

Bottom line

From a medical perspective, the question "is the flu shot necessary?" is now expressed differently than in popular articles of the past. A more accurate statement is that annual vaccination is widely recommended, and for certain groups, it is especially important because they are at higher risk of pneumonia, decompensation of chronic diseases, hospitalization, and death. The WHO, CDC, ECDC, and the NHS agree on this basic principle. [32]