Influenza, commonly called the flu, poses a serious health threat to older adults. According to the Centers for Disease Control and Prevention, approximately 70-85% of seasonal flu-related deaths and 50-70% of flu-related hospitalizations occur in adults aged 65 years and older. While influenza affects people of all ages, seniors face higher risk of severe complications including pneumonia, hospitalization, and death. Understanding influenza prevention, recognizing symptoms early, and knowing when to seek treatment can significantly reduce serious outcomes.
Why Influenza Is More Dangerous for Seniors
Aging naturally weakens the immune system through a process called immunosenescence, reducing the body's ability to fight infections effectively. T cells and B cells, critical components of immune defense, become less responsive to new threats. This immune decline means seniors not only catch infections more easily but also experience more severe illness and slower recovery compared to younger adults.
Chronic health conditions common in older adults further compound influenza risk. Conditions like heart disease, diabetes, chronic lung disease, kidney disease, and cancer make the body less resilient to infection stress. Influenza can destabilize these chronic conditions, triggering heart attacks in people with heart disease, worsening glucose control in diabetes, and causing respiratory failure in people with chronic lung disease.
Age-related changes in lung function, including reduced elasticity and weaker respiratory muscles, impair the lungs' ability to clear mucus and fight respiratory infections. This increases pneumonia risk, the most common serious influenza complication. Frailty, characterized by decreased physiological reserve and increased vulnerability to stressors, further elevates risk of severe outcomes including hospitalization, prolonged illness, functional decline, and death.
Understanding Influenza Virus and Transmission
Influenza is caused by influenza viruses, primarily types A and B that circulate seasonally. Influenza A viruses are categorized by two surface proteins—hemagglutinin (H) and neuraminidase (N)—creating subtypes like H1N1 and H3N2. These viruses constantly mutate, which is why new flu vaccines are formulated each year to match circulating strains and why you can get the flu multiple times throughout your life.
Flu season in the United States typically runs from October through May, peaking between December and February, though timing and severity vary by year. Influenza spreads primarily through respiratory droplets when infected people cough, sneeze, or talk. These droplets can land in the mouths or noses of nearby people or be inhaled into the lungs. Less commonly, people can contract flu by touching surfaces contaminated with flu virus and then touching their mouth, nose, or eyes.
Infected individuals can spread influenza starting one day before symptoms develop and continuing for five to seven days after becoming sick, though some people, particularly those with weakened immune systems, may spread the virus for longer periods. This asymptomatic transmission period makes flu prevention challenging, as people spread the virus before knowing they're sick.
Recognizing Influenza Symptoms and Complications
Influenza typically comes on suddenly rather than gradually. Classic flu symptoms include fever (though not all older adults develop high fever with flu), chills and sweats, headache, dry persistent cough, muscle aches and pains (myalgia), particularly in the back, arms, and legs, fatigue and weakness that can last weeks, nasal congestion, and sore throat. These symptoms typically last one to two weeks, with fatigue sometimes persisting longer.
It's important to distinguish influenza from the common cold, which develops gradually and causes milder symptoms. Colds rarely cause fever or significant body aches and are less likely to lead to serious complications. However, only laboratory testing can definitively distinguish influenza from other respiratory infections.
Older adults may experience atypical influenza presentations. Some seniors develop flu without fever, making diagnosis more challenging. Confusion or altered mental status may be prominent symptoms, particularly in those with dementia. Weakness, falls, and functional decline may be presenting signs rather than classic respiratory symptoms. This atypical presentation often delays diagnosis and treatment, increasing complication risk.
Serious influenza complications requiring medical attention include pneumonia (bacterial or viral), bronchitis, sinus infections, and ear infections. Worsening of chronic medical conditions like heart failure, asthma, or diabetes is common. Myocarditis (heart muscle inflammation) and encephalitis (brain inflammation) are rare but serious complications. Sepsis, the body's life-threatening response to infection, can develop in severe cases.
Warning signs requiring immediate medical attention include difficulty breathing or shortness of breath, persistent chest pain or pressure, persistent dizziness or confusion, inability to wake up or stay awake, severe weakness or unsteadiness, seizures, worsening of chronic medical conditions, severe or persistent vomiting, and flu symptoms that improve but then return with fever and worse cough.
Influenza Vaccination: Your Best Protection
Annual influenza vaccination represents the single most effective way to prevent flu and its complications. The CDC's Advisory Committee on Immunization Practices recommends that everyone aged 6 months and older receive annual flu vaccination, with particular emphasis on high-risk groups including all adults aged 65 years and older.
Special high-dose flu vaccines specifically designed for seniors provide better protection than standard-dose vaccines. Fluzone High-Dose Quadrivalent contains four times the antigen (the part that stimulates immune response) as standard-dose flu vaccines. FLUAD Quadrivalent contains an adjuvant, an ingredient that helps create a stronger immune response. Flublok Quadrivalent is a recombinant flu vaccine containing three times the antigen of standard-dose vaccines.
Studies demonstrate these enhanced vaccines provide better protection for seniors. A large study published in The Lancet Respiratory Medicine found that high-dose flu vaccine was 24% more effective than standard-dose vaccine at preventing flu-related medical encounters in adults aged 65 and older. Another study showed high-dose vaccine reduced hospitalizations by 28% compared to standard-dose vaccine.
The best time to get vaccinated is early in flu season, ideally by the end of October, allowing your body time to develop immunity before flu activity peaks. However, getting vaccinated later still provides protection, as flu activity can continue into spring. It takes about two weeks after vaccination for antibodies to develop and provide protection.
Flu vaccines are safe for seniors. Common side effects include soreness, redness, or swelling at the injection site, low-grade fever, and mild body aches, typically lasting one to two days. These side effects are much milder than actual influenza. Serious side effects are extremely rare. You cannot get the flu from the flu vaccine, as it contains either inactivated (killed) virus or no flu virus at all (in recombinant vaccines).
Medicare Part B covers one flu shot per flu season at no cost to you when provided by a participating provider, including both standard and high-dose vaccines. Most Medicare Advantage plans also cover flu vaccination at no cost.
Antiviral Treatment: When to Use and What to Expect
Antiviral medications can treat influenza by shortening illness duration, reducing symptom severity, and preventing serious complications. These prescription medications work best when started within 48 hours of symptom onset, though they may still provide benefits when started later, particularly in hospitalized patients or those at high risk for complications.
Four FDA-approved antiviral medications are available for influenza treatment. Oseltamivir (Tamiflu) is an oral medication taken twice daily for five days, the most commonly prescribed antiviral for flu. Zanamivir (Relenza) is an inhaled powder taken twice daily for five days, though not recommended for people with respiratory conditions like asthma or COPD. Peramivir (Rapivab) is a single-dose intravenous medication administered in healthcare settings. Baloxavir marboxil (Xofluza) is a single-dose oral medication.
Research demonstrates antivirals reduce flu illness duration by about one day when started early. More importantly for seniors, early antiviral treatment reduces hospitalization risk by approximately 40% and may reduce mortality risk. For people already hospitalized with flu, antiviral treatment reduces death risk and shortens hospital stays.
All adults aged 65 and older with confirmed or suspected influenza should receive antiviral treatment, regardless of vaccination status and regardless of time since symptom onset, according to CDC recommendations. Don't wait for laboratory confirmation if flu is suspected—starting treatment promptly is more important than confirming the diagnosis first.
Common side effects of oseltamivir include nausea and vomiting, usually mild and improving if taken with food. Zanamivir may cause bronchospasm in people with lung disease. Baloxavir has few side effects but may have reduced effectiveness in people with influenza A(H3N2) infections. Medicare Part D typically covers antiviral medications, though copays vary by plan.
Additional Prevention Strategies
While vaccination is paramount, additional strategies further reduce influenza risk. Practice good hand hygiene by washing hands frequently with soap and water for at least 20 seconds, particularly after being in public spaces, before eating, and after coughing, sneezing, or blowing your nose. Use alcohol-based hand sanitizer containing at least 60% alcohol when soap and water aren't available.
Avoid close contact with sick people, maintaining at least six feet of distance when possible. If you're sick with flu-like symptoms, stay home to avoid spreading infection to others. Cover coughs and sneezes with tissues or the inside of your elbow rather than your hands. Avoid touching your face, particularly your eyes, nose, and mouth, where viruses can enter your body.
Clean and disinfect frequently touched surfaces like doorknobs, light switches, phones, keyboards, and remote controls, especially when someone in your household is sick. Consider wearing a mask in crowded indoor spaces during flu season, particularly if flu activity is high in your community. Masks help prevent both acquiring and spreading respiratory viruses.
Maintain overall health through adequate sleep (seven to nine hours nightly), regular physical activity to support immune function, nutritious diet rich in fruits, vegetables, and whole grains, stress management, and keeping chronic conditions well-controlled through medication adherence and regular medical care. These foundational health practices strengthen your immune system's ability to fight off infections.
Ensure household contacts, particularly caregivers and family members who interact with you regularly, receive annual flu vaccination. This creates a protective barrier, reducing your exposure risk.
When to Seek Medical Care
Contact your healthcare provider promptly if you develop flu symptoms, even if they seem mild initially. Early antiviral treatment is most effective, and your provider can assess your risk for complications. Don't wait to see if symptoms worsen—proactive treatment produces the best outcomes.
Seek immediate medical attention if you experience warning signs of complications including difficulty breathing, chest pain, confusion, inability to eat or drink, severe vomiting, no urination, or severe weakness and dizziness. Call 911 for life-threatening symptoms rather than driving yourself to the emergency department.
After recovering from flu, gradually resume normal activities as energy returns. Don't rush recovery, as premature exertion can prolong fatigue. Continue to monitor for delayed complications like secondary bacterial pneumonia, which can develop even after initial flu symptoms improve. Persistent or worsening cough, new or returning fever, and difficulty breathing after initial improvement warrant medical evaluation.
Influenza poses serious risks to seniors, but these risks can be dramatically reduced through annual vaccination with high-dose or adjuvanted vaccines, early recognition of symptoms, prompt antiviral treatment, and consistent preventive measures. Work with your healthcare provider to ensure you receive appropriate preventive care and know the action plan should flu symptoms develop. Taking influenza seriously and acting proactively protects your health and reduces the risk of serious complications.