Inflúensa

Inflúensa, also known as influenza, is an acute viral infection of the respiratory tract caused by influenza viruses A, B, and C. It commonly presents with fever, cough, sore throat, nasal congestion, muscle aches, and fatigue. Symptoms often appear suddenly. Seasonal outbreaks occur annually in temperate regions, and the disease can be more severe in young children, older adults, pregnant people, and those with chronic illnesses.

Cause and transmission: Influenza A and B are responsible for most epidemics; influenza C causes milder illness and does not trigger major outbreaks. The viruses spread mainly through respiratory droplets when an infected person coughs or sneezes and can spread by touching contaminated surfaces. The incubation period is about 1 to 4 days, and people are contagious from before symptoms begin until several days after.

Diagnosis and treatment: Diagnosis is often clinical, but laboratory tests such as RT-PCR or rapid antigen tests can confirm infection. Most healthy individuals recover with supportive care, including fluids and rest. Antiviral medications (for example, oseltamivir, baloxavir, zanamivir) may shorten illness if started early and are especially recommended for high‑risk groups or severe disease.

Prevention: Annual vaccination is the primary protection against influenza and is recommended for most people aged six months and older. Vaccines are reformulated yearly to match circulating strains and reduce the risk of illness and complications. Additional measures include hand hygiene, respiratory etiquette, avoiding close contact with ill people, and, in some settings, masks during outbreaks.

Impact: Influenza causes significant global morbidity and mortality, leading to hospitalizations and deaths, particularly among the elderly, young children, and pregnant people. Public health surveillance tracks circulating strains to guide vaccine composition and outbreak responses.