Understanding Influenza: Symptoms, Risks, Prevention, and Treatment
Influenza is a contagious respiratory illness involving the nose, throat, and sometimes the lungs. It occurs seasonally in the United States between October and March. Influenza can cause pneumonia, especially in individuals at the extremes of age and in high-risk populations.
About 3 to 11% of the U.S. population gets sick from influenza annually. Children under 5 years old, individuals aged 65 or above, and those with other medical conditions can develop severe illness, resulting in hospitalization and sometimes death.
Symptoms
The most common symptoms include:
- Fever or feeling feverish with chills
- Cough
- Sore throat
- Runny or stuffy nose
- Muscle or body aches
- Headaches
- Fatigue
- Vomiting and diarrhea (mostly seen in children)
When Can Patients Spread Infections to Others?
- Influenza is highly contagious during the first three days of illness.
- Contagiousness begins one day before symptoms appear and lasts for another five to seven days.
- Individuals with weakened immune systems can remain infective for a longer time.
High-Risk Individuals
High-Risk Factors
- 65 years and older
- 2 years and younger
- Asthma
- Chronic Obstructive Pulmonary Disease (COPD)
- Neurologic and neurodevelopmental conditions
- Cystic fibrosis
- Sickle cell disease
- Diabetes mellitus
- Congestive heart failure
- Congenital heart disease
- Coronary artery disease
- Chronic renal failure
- Inherited metabolic disorders
- Liver disorders
- Mitochondrial disorders
- BMI of 40 kg/m² or higher
- Younger than 19 years on aspirin therapy
- HIV
- Cancers (e.g., leukemia)
- Chemotherapy
- Chronic steroid therapy
- Radiation treatment
- Stroke
- Muscle disorders (e.g., myopathies)
- Difficulty coughing, swallowing, or clearing airways
- Chronic lung disease
How Does the Infection Spread?
Influenza spreads through respiratory droplets released when an infected person coughs, sneezes, or talks. These droplets can remain viable on surfaces for up to 24 hours, making it easy to transmit.
How to Avoid Flu Infection
The primary prevention method is vaccination:
- Annual influenza vaccinations are recommended.
- Vaccination reduces the risk of severe complications and hospitalization.
Other preventive measures include:
- Practicing good hand hygiene
- Avoiding close contact with sick individuals
- Covering your nose and mouth when coughing or sneezing
Testing and Diagnosis
If you experience flu-like symptoms, especially if you belong to a vulnerable group, seek prompt medical attention:
- Get tested at your primary care office, urgent care, or the emergency department.
- If you live with high-risk individuals, ensure they receive annual flu vaccinations and, if necessary, preventive medications.
All healthcare providers are mandated to receive annual flu vaccinations.
Treatment
The antiviral medication Oseltamivir (Tamiflu) is the preferred treatment for influenza:
- FDA-approved for use in children as young as 2 weeks old.
- Early treatment reduces symptom severity and duration.
