Health Advisory – Seasonal Influenza (Flu)

What is Influenza?

Influenza ("flu") is a contagious respiratory illness caused by influenza viruses that infect the nose, throat, and sometimes the lungs. Influenza can range from a mild to severe illness and may result in hospitalization or death, particularly in vulnerable individuals. Influenza viruses spread primarily through respiratory droplets generated when infected individuals cough, sneeze, speak, or breathe in close proximity to others. Transmission may also occur through contact with contaminated surfaces followed by touching the eyes, nose, or mouth.

Signs and Symptoms

Travel Guard recommends that all travellers familiarize themselves with the common signs and symptoms of influenza and seek medical advice promptly if symptoms develop.

Common symptoms include:

• Fever or feeling feverish/chills
• Cough
• Sore throat
• Runny or stuffy nose
• Muscle or body aches
• Headache
• Fatigue or unusual tiredness
• Vomiting and diarrhea (more common in children than adults)

Individuals at Increased Risk of Influenza Complications

Some individuals are at increased risk of serious illness, hospitalization, or complications from influenza. These include:

• Adults aged 65 years and older
• Children younger than five years, especially those younger than two years
• Pregnant individuals and those up to two weeks postpartum
• Individuals living in nursing homes or long-term care facilities
• Individuals with asthma, chronic lung disease, or chronic obstructive pulmonary disease (COPD)
• Individuals with heart disease, including heart failure and coronary artery disease
• Individuals with diabetes or other endocrine disorders
• Individuals with liver or kidney disease
• Individuals with neurological or neurodevelopmental disorders
• Individuals with certain blood disorders
• Individuals with weakened immune systems due to medical conditions or medications
• Individuals with severe obesity (BMI ≥40 kg/m²)

Travelers within these groups should exercise particular caution and seek medical advice promptly if influenza is suspected.

Influenza Vaccination

Annual influenza vaccination remains the most effective method of reducing the risk of influenza infection and its complications. Public health authorities recommend vaccination for all individuals aged six months and older unless medically contraindicated. Vaccination is particularly important for those at increased risk of severe illness.

Influenza viruses continually evolve, and vaccine formulations are reviewed and updated annually by the World Health Organization (WHO) and national health authorities to provide protection against the strains most likely to circulate during the upcoming influenza season.

Children younger than six months cannot receive influenza vaccination and rely on the vaccination of parents, caregivers, family members, and healthcare workers for indirect protection.

Medical Management and Treatment

Individuals with suspected influenza who are at increased risk of complications, have severe symptoms, or require hospitalization should seek medical attention as soon as possible.

Healthcare providers may prescribe antiviral medications, which can:

• Reduce symptom severity
• Shorten illness duration
• Lower the risk of certain complications
• Improve outcomes in hospitalized patients

Antiviral treatment is most effective when started within 48-hours of symptom onset; however, treatment may still provide benefit in high-risk patients and hospitalized individuals even when initiated later. Clinicians may begin treatment based on clinical suspicion without waiting for laboratory confirmation.

Current approved antiviral medications may include:

• Oseltamivir (Tamiflu)
• Zanamivir (Relenza)
• Peramivir (Rapivab)
• Baloxavir marboxil (Xofluza)

The choice of antiviral medication should be determined by the treating healthcare provider.

Travel Guard Recommendations for Preventing Influenza

Travel Guard recommends the following measures to reduce the risk of influenza infection while traveling:

Infection Prevention

• Obtain an annual influenza vaccination before travel.
• Avoid close contact with individuals who are ill whenever possible.
• Minimize time spent in crowded indoor settings during known outbreaks.
• Wash hands frequently with soap and water for at least 20 seconds.
• Use an alcohol-based hand sanitizer when soap and water are unavailable.
• Avoid touching the eyes, nose, and mouth with unwashed hands.
• Cover coughs and sneezes with a tissue or elbow.
• Dispose of used tissues appropriately and perform hand hygiene afterward.

Health and Wellness

• Maintain adequate hydration.
• Eat a balanced and nutritious diet.
• Get sufficient sleep and rest.
• Engage in regular physical activity where appropriate.
• Manage chronic medical conditions as advised by healthcare providers.

Travel Planning

• Review local public health and travel advisories before departure.
• Carry an adequate supply of prescribed medications.
• Seek medical attention promptly if influenza symptoms develop during travel.
• If experiencing fever, remain isolated from others as much as possible until fever-free for at least 24-hours without the use of fever-reducing medications, unless medical care is required.

Key Message

Influenza remains a significant global health concern and continues to cause substantial illness, hospitalizations, and deaths each year. Annual vaccination, good hand hygiene, respiratory etiquette, and timely medical assessment for high-risk individuals remain the cornerstones of influenza prevention and management.

Sources

·         Centers for Disease Control and Prevention (CDC) – Influenza (Flu) Guidance and Prevention Information. [cdc.gov]

·          CDC – People at Increased Risk for Flu Complications. [cdc.gov]

·          World Health Organization (WHO) – Treating Flu with Antiviral Drugs. [who.int]

·          WHO – Influenza Antiviral Medications: Summary for Clinicians. [who.int]

·          WHO – Recommendations for Influenza Vaccine Composition 2025–2026. [who.int]