INFLUENZA VACCINE: WHAT YOU NEED TO KNOW
Seasonal influenza is one of the most common infectious diseases during autumn and winter, with a significant impact on both individual health and healthcare costs. In at-risk populations—such as the elderly, individuals with chronic conditions, and immunocompromised patients—complications can be severe. Influenza vaccination remains the primary preventive measure; however, it is important to understand how it works, its benefits and limitations, the optimal timing for administration, and, for those seeking complementary support, the potential role of natural interventions such as Referol Immuno by Eidon Salus.
In this article, we will:
- Explain what the influenza vaccine is and how it works;
- Examine the advantages and limitations, with data from studies and official sources;
- Define the optimal period for vaccination;
- Answer the most frequently asked questions;
- Introduce the use of Referol Immuno as a natural adjunct, supported by available scientific evidence
What the Influenza Vaccine Is and How It Works
The influenza vaccine is a seasonal vaccine containing inactivated viral components (or, in some formulations, attenuated viruses) designed to stimulate the production of antibodies against the influenza strains predicted for the current season.
- Immune response timing: It takes approximately two weeks after vaccination for immunity to become effective.
- Seasonal variability: Vaccine efficacy can vary significantly from season to season, depending on the “match” between vaccine strains and circulating strains, as well as individual factors such as age and health status.
- Elderly people: Immune response may be attenuated due to immunosenescence; therefore, enhanced formulations (adjuvanted or high-dose vaccines) are available to improve immunogenicity.
- Overall protection: While the vaccine does not confer 100% immunity, it reduces the likelihood of contracting influenza and, if infection occurs, tends to mitigate disease severity, lowering hospitalization rates, complications, and mortality.
For example, a CDC study estimated that during the 2019–2020 season, influenza vaccination prevented approximately 7 million cases of influenza, 100,000 hospitalizations, and 7,000 deaths.
Optimal Timing for Influenza Vaccination
A common question is: When is the best time to get the flu vaccine?
- Italy: Vaccination campaigns typically start in early October and run through December.
- United States (CDC recommendation): Most people should be vaccinated between September and October, ideally by the end of October, to ensure protection during the peak influenza period.
- Duration of protection: Vaccine-induced immunity tends to wane over time. One study suggests efficacy begins to decrease around 41 days post-vaccination, with an estimated reduction of 9% every 28 days.
- Late vaccination: Even getting vaccinated later (e.g., November or December) can be beneficial; partial protection is better than none.
In summary: The optimal window for vaccination is late September to late October, but vaccination later in the season still provides meaningful protection.
Pros and Cons of the Influenza Vaccine
Key Benefits (Pros)
- Reduced Risk of Influenza
Vaccine efficacy varies by season, but in years with a good strain match, it can reach 70–90% in certain population groups. - Mitigation of Disease Severity
Even when infection occurs, vaccinated individuals generally experience milder symptoms, with lower risk of complications, hospitalization, and death. - Reduced Hospitalizations and Healthcare Costs
High-dose or more effective vaccines have shown a greater impact on preventing cardiovascular events and cardiorespiratory hospitalizations compared to standard formulations. A cost-effectiveness analysis in individuals over 65 showed that high-dose quadrivalent vaccines provide an estimated ~24% relative advantage over standard vaccines in preventing cardiorespiratory hospitalizations. - Benefits for Vulnerable Populations
In elderly and frail individuals, vaccination is among the most effective interventions to preserve health. A 2023–24 Italian study estimated that influenza vaccination reduced nearly 50% of deaths and hospitalizations due to influenza and pneumonia in older adults. When combined with pneumococcal and COVID-19 vaccines, effectiveness can reach approximately 80%. - Indirect Community Protection
Vaccinating the most vulnerable also reduces viral circulation in the general population, protecting individuals who cannot be vaccinated (e.g., infants).
Limitations and Contraindications (Cons)
- Variable Efficacy and Waning Immunity
Protection can decrease progressively after a few months, making timing of vaccination critical. - Mismatch Between Predicted and Circulating Strains
If the vaccine strains do not align well with circulating influenza viruses, protection may be reduced. - Reduced Response in Immunocompromised or Elderly Individuals
These groups may have a weaker immune response, which is why many countries prioritize enhanced formulations for older adults. - Potential Side Effects
As with all vaccines, adverse effects may occur, which will be discussed in a dedicated section. - Critiques and Controversies
Some studies have questioned the utility of influenza vaccination in healthy elderly individuals without cardiovascular disease, though such views remain minority positions.
Conclusion: Overall, the benefits far outweigh the risks, especially in vulnerable populations. The principle of “partial protection is better than none” applies strongly in the context of influenza vaccination.
Flu vaccine side effects: what to expect
Common Side Effects
Influenza vaccine side effects are generally mild, transient, and self-limiting. The most frequent include:
- Pain, redness, or swelling at the injection site
- Headache, muscle aches (myalgia), fatigue
- Low-grade fever, general malaise
- Severe allergic reactions are extremely rare
These symptoms usually resolve within 24–48 hours. Important note: the vaccine cannot cause influenza, as it contains inactivated (or attenuated) viruses, not live viruses.
Onset of Side Effects
Typical side effects appear within a few hours up to the first couple of days after vaccination and generally resolve within 1–2 days.
Rare or Controversial Risks
- Severe allergic reactions are extremely rare but require immediate management in appropriate medical settings.
- There is no reliable evidence that the influenza vaccine triggers autoimmune diseases, such as type 1 diabetes or multiple sclerosis.
- A recent study observed a slight, transient prolongation of the menstrual cycle (less than 1 day) in some cases, but the effect is minimal and temporary.
Summary: For the vast majority of people, the risk of serious side effects is very low and far outweighed by the protective benefits of vaccination.
Influenza Vaccine in Pharmacies: Free Access and Costs
Free influenza vaccination
In Italy, the influenza vaccine is provided free of charge by the National Health Service (SSN) for at-risk groups, including: Elderly individuals (generally ≥65 years), people with chronic conditions, pregnant women, immunocompromised individuals, healthcare workers.
The procedures and eligibility criteria may vary by region, so it is advisable to check with your local ASL or healthcare authority.
Influenza Vaccine in Pharmacies: Cost
Outside the groups eligible for free vaccination through the SSN, the influenza vaccine can be purchased at pharmacies. Costs depend on the type of vaccine (standard, adjuvanted, high-dose) and the brand, and can vary significantly between regions.
Pharmacy prices are determined by local contracts and availability, but a reasonable range is €24–€34, similar to seasonal vaccine costs in other European countries.
For individuals in at-risk groups, it is recommended to use the free SSN vaccination campaign whenever available.
Influenza Vaccine in Adults
- Healthy adults: Annual vaccination is recommended.
- Priority groups: Adults with chronic diseases, obesity, immunocompromised conditions, smokers, and pregnant women.
- Elderly (≥65 years): High-dose or adjuvanted vaccines may be indicated to overcome reduced immune response.
Influenza Vaccine in Children
- In some countries, vaccination of healthy children is not routinely recommended, except for those with predisposing conditions.
- When recommended, children under 9 years old who have never been vaccinated may require two doses at least four weeks apart.
- National and regional guidelines define specific criteria, so consultation with a pediatrician or local health service is advised.
Duration of Protection
A key question is: How long does influenza vaccine protection last?
- Immunity typically lasts 6–8 months.
- Optimal protection may begin to decline after a few months; studies indicate efficacy can start decreasing 3–4 months post-vaccination, which is why vaccination too early (e.g., in July) is not recommended.
- Due to antigenic drift of influenza viruses, vaccination must be repeated annually—even individuals vaccinated last year are not protected for the new season.
Referol Immuno: A Natural Support for Immune Defenses
Following a thorough discussion of the influenza vaccine, it is important to clarify that Referol Immuno is not a substitute for vaccination. Rather, it is a natural complementary support designed to enhance the immune system, especially during periods of higher risk.
Referol Immuno, developed by Eidon Salus, is formulated to:
- Stimulate immune defenses
- Exert antiviral and anti-inflammatory effects
- Support relief from cough
- Restore intestinal flora through probiotics
Its formulation combines four adaptogenic active ingredients—astragalus, eleuthero, echinacea, and resveratrol—with natural sources of Vitamin C (acerola, rosehip) and 10 billion probiotics (5 strains: Acidophilus, Rhamnosus, Bifidum, Bulgaricus, Thermophilus).
What is the scientific evidence supporting it?
- Astragalus: In in vivo studies, shown to increase IgA and IgG levels, reducing the incidence of respiratory infections.
- Echinacea: Clinical studies recognize its role in Germany as a supportive therapy for viral influenza infections.
- Prophylactic use of Echinacea in patients with recurrent respiratory infections has been shown to reduce symptoms and duration of influenza.
- Probiotics: Helpful when antibiotics are used (e.g., for secondary bacterial infections), as they restore and balance the intestinal microbiota.
Expected Benefits
- Enhanced immune defenses
- Reduced viral replication
- Shortened duration and lower frequency of influenza episodes
- Support in alleviating cough
- Restoration of gut microbiota, particularly important during or after antibiotic therapy
Warnings
Referol Immuno does not replace the influenza vaccine and does not provide specific immunity against influenza virus strains; it acts as a general immune support. It should be used according to the recommended dosage, and in cases of chronic disease or ongoing medication, medical advice is recommended.
Conclusions
Influenza vaccination remains the most effective and well-established tool to prevent influenza and its complications, particularly in the elderly and frail. Despite limitations related to viral strain variability and individual immune response, benefits in terms of reducing illness, hospitalizations, and mortality are well-documented.
Nutraceutical support with Referol Immuno can serve as a valuable complement, useful both during the acute phase and as prophylaxis, to stimulate natural defenses and support immune recovery.
Remember: Consulting a physician or pharmacist is essential to determine the best strategy for your health, including vaccination and possible complementary support.
FAQ
It is recommended for everyone aged ≥6 months (unless contraindicated), with priority for elderly individuals, patients with chronic diseases, immunocompromised people, pregnant women, and healthcare workers.
Yes, for at-risk groups in many regions via the SSN. Those not included in these categories can purchase it at pharmacies.
Ideally, late September to late October, although vaccination later (November or December) is still better than not vaccinating at all.
Pain at the injection site, headache, muscle aches, mild fever. These generally resolve within 1–2 days. Severe reactions are very rare.
