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For individuals with chronic illnesses (underlying conditions) such as diabetes, heart disease, or COPD (Chronic Obstructive Pulmonary Disease), influenza is not just a common cold; it is an extremely dangerous threat that increases the risk of severe illness, hospitalization, and death by 5 to 10 times or more. Especially since a highly virulent Type A virus is predicted to circulate in the 2025 season, vaccination is positioned as an "essential medical procedure to save lives."While the prevention of illness for people with underlying conditions may be a moderate 30% to 50%, the influenza vaccine demonstrates overwhelming figures for the prevention of severe illness (80% to 95%) and prevention of hospitalization (70% to 90%). Scientific evidence clearly shows that the mortality risk increases by 60% to 80% if the shot is not administered.

The side effects that occur after an influenza vaccination, such as "sore arm," "fever," and "malaise," are essentially "proof that your immune system has properly awakened" and is preparing to fight the virus.The true nature of the side effect is the release of inflammatory substances called "cytokines" by immune cells (macrophages) that recognize the foreign material (vaccine antigen) in the body. If these cytokines cause local blood vessels to dilate, it leads to arm swelling; if they stimulate the brain's thermoregulatory center, it leads to fever. Fever is an "immune strategy" designed to activate the immune system and is by no means a sign of a weak body.

Getting the influenza vaccine is an essential preventative measure for children (6 months to 12 years old) who are in group settings, as it helps contain the epidemic and prevents severe illness in the child themselves. For children under 13 years old, "2 doses" are mandatory to ensure proper immunity, and it is recommended to receive them 2 to 4 weeks apart.As of 2025 data, children who complete the two-dose series have an illness prevention rate of 70% to 90%, and critically, the prevention of severe complications like encephalopathy and pneumonia is nearly 100%. Furthermore, good news: many municipalities offer robust subsidy programs, making the actual cost of vaccination virtually ¥0 to ¥4,000 (for both doses combined).

"Can I use health insurance for the influenza shot?"Since the influenza vaccine is intended for "prevention" rather than "treatment" of illness, it is absolutely not covered by public health insurance (National Health Insurance or Social Insurance), meaning it is 100% self-pay. This is the fundamental principle.However, a public system is in place in Japan to significantly reduce this self-pay expense. Specifically, routine vaccination for those aged 65 and over is made virtually free through public funds (taxes), and it is very common for children to receive subsidies from local municipalities and for company employees to receive assistance from their health insurance unions.

The influenza vaccine is not covered by public health insurance (100% self-pay), so the fee varies depending on the medical institution, vaccine type, and local subsidy programs. As of 2025, the standard price range for adults is ¥3,500 to ¥5,000 per dose. While children are recommended to receive two doses (effectively double the cost), numerous cases show that local government subsidies can reduce the cost by nearly half.(Reference: Based on data from the Ministry of Health, Labour and Welfare, local governments, and medical institutions. Prices are inclusive of tax, estimated, and subject to change. Prior booking and confirmation are advised.)

"I got the shot, but I still got the flu..."When faced with this situation, you might feel disappointed and think, "Was the vaccine pointless?" However, the 2025 medical data shows that 99.9% of people who contract the flu after vaccination only experience symptoms at the "level of a mild cold." This is the "true value" of the influenza vaccine.The vaccine is not a medication that reduces infection to zero. Its greatest effect is to prevent severe illness and turn what would have been a hellish week into a mild two to three days.

The influenza vaccine does not confer equal protection to everyone. Latest data shows that individuals who experience "immunosenescence" (immune aging), particularly those aged 80 and over, as well as those taking immunosuppressants or suffering from severe obesity, may not achieve the expected antibody levels from standard vaccines, leading to a significant drop in preventative effectiveness.As of 2025, the reason people feel the vaccine "doesn't work" is often the combination of "Ages 80+ + Standard Vaccine."

The perception that "The flu shot is pointless because I get the flu even when I get vaccinated"—misunderstands the vaccine's "true value."The latest 2025 data reveals that the vaccine's effect is not merely about "reducing infection to zero," but about "making the illness extremely mild if contracted, thus minimizing the damage to your life."The effectiveness in preventing severe illness is particularly high, ranging from 70% to 95% across all age groups. The difference between vaccinated and unvaccinated individuals is stark: a 10-fold difference in the probability of hospitalization for seniors, and a 20 to 30-fold difference in the chance of being confined to bed with a high fever for five days. Furthermore, the introduction of highly effective vaccines like Fluad® (for the elderly) and the Recombinant Vaccine this year means that those aged 65 and over can expect the highest level of prevention ever recorded.

The belief that "I have an egg allergy, so I can't get the flu shot" is now completely outdated information.Conventional influenza vaccines were manufactured using chicken eggs. However, due to advances in purification technology and the introduction of the "Recombinant HA Vaccine (Supemtek®)" debuting in Japan in 2025, almost everyone with an allergy can now be safely vaccinated.The completely egg-free recombinant vaccine is a long-awaited option, especially for those with severe egg allergies (history of anaphylaxis). Furthermore, people with gelatin or latex allergies can also avoid risk with the recombinant vaccine.

One of the biggest reasons people hesitate to get the influenza vaccine may be anxiety over "severe side effects." Serious adverse reactions like anaphylaxis, Guillain-Barré Syndrome (GBS), and Acute Disseminated Encephalomyelitis (ADEM)—which sound alarming—do indeed exist.However, the latest data from the Ministry of Health, Labour and Welfare (MHLW) and clinical practice as of 2025 demonstrates that the frequency of these occurrences is extremely rare. Anaphylaxis occurs in only 1 to 2 people per million—a rate less than 1/10th the chance of dying in a plane crash and less than 1/1000th the chance of dying in a traffic accident.