Comprehensive Guide to Influenza: Types, Symptoms, and Prevention

Influenza, commonly known as the flu, is a contagious respiratory infection caused by a virus. It spreads easily through coughing, sneezing, or direct contact, such as handshakes. People can transmit the virus one to two days before symptoms appear and up to a week afterward. Seasonal flu results in thousands of deaths annually, with around 3,000 to 49,000 fatalities and 200,000 hospitalizations in some regions. Since antibiotics are ineffective against viruses, annual vaccination remains the best prevention method.

However, certain individuals, such as those with severe egg allergies, should avoid the vaccine. Here’s essential information about flu types, symptoms, and prevention strategies.

What are the different seasonal flu types?
Influenza viruses are categorized into three main types: A, B, and C. Here is a detailed overview:

Type A - This type infects both animals and humans, often causing widespread epidemics. Wild animals typically serve as natural hosts, and the virus is prone to frequent mutations, leading to significant outbreaks.

Type B - Found only in humans, type B usually causes milder illness compared to type A, though severe cases can occur. It does not cause pandemics and lacks subtypes.

Type C - Milder than types A and B, type C infections are generally less severe and do not lead to large-scale outbreaks.

Key symptoms and signs of influenza
While flu symptoms often resemble those of a cold, certain signs can help distinguish them:

Fever exceeding 100.4°F

Body aches and joint pain

Headache

Chills and sweating

Fatigue and weakness

Nausea, diarrhea, and vomiting

When is medical attention necessary?
Seek medical care if:

you're elderly or immunocompromised

fever persists beyond four to five days

symptoms worsen or are severe

you experience chest pain or difficulty breathing

Factors increasing flu risk
While most infections are mild, certain groups face higher risks of complications, including:

young children and infants

adults over 65

pregnant women

individuals with chronic illnesses like kidney or heart disease

those with weakened immune systems

people on steroids or undergoing cancer treatment

How to treat the flu?
Since influenza is viral, antibiotics are ineffective unless a bacterial complication develops. Doctors may prescribe antiviral medications in some cases. Symptomatic relief can be achieved with painkillers, under medical guidance. Rest, hydration, warmth, and good nutrition are vital. To prevent spreading, infected individuals should avoid contact, refrain from smoking or alcohol, and inform close contacts.