From the Guidelines
Influenza A symptoms typically include sudden onset of high fever, chills, cough, headache, sore throat, fatigue, nasal stuffiness, and conjunctivitis.
Common Symptoms
- High fever
- Chills
- Cough
- Headache
- Sore throat
- Fatigue
- Nasal stuffiness
- Conjunctivitis These symptoms are commonly reported in both adults and children, as seen in studies 1.
Additional Symptoms in Children
- Otitis media
- Nausea
- Vomiting
- Febrile seizures (in 6%–20% of children hospitalized with influenza virus infection) 1 A clinical prediction model from North America for influenza in children has shown that the triad of cough, headache, and pharyngitis had a sensitivity of 80% and a specificity of 78% for a positive viral culture for influenza 1.
Duration of Symptoms
- Fever tends to settle 2–4 days later
- Dry cough and clear nasal discharge can last for 1–2 weeks 1
- Uncomplicated influenza illness typically resolves after 3–7 days for the majority of persons, although cough and malaise can persist for >2 weeks 1
From the Research
Symptoms of Influenza A
The symptoms of Influenza A (Influenza Type A) include:
- Abrupt onset of fever, cough, chills or sweats, myalgias, and malaise 2
- Fever, chills, aches, pains, headaches, fatigue, cough and generalized weakness that can last up to 14 days 3
- Fever > 38 degrees C, cough and dyspnoea are the major symptoms on presentation 4
- High fever, body aches, and fatigue 5
- Pharyngitis, dyspnea were frequent symptoms in influenza A 6
Common Symptoms
Common symptoms of Influenza A include:
- Fever
- Cough
- Chills or sweats
- Myalgias
- Malaise
- Headaches
- Fatigue
- Dyspnea
Gastrointestinal Symptoms
Gastrointestinal symptoms such as:
- Watery diarrhoea
- Vomiting
- Abdominal pain are common early in the course of the disease, particularly in human H5N1 infection 4
Laboratory Features
Laboratory features of human H5N1 infection include:
- Leucopoenia, especially lymphopenia
- Elevated amino-transaminases
- Thrombocytopenia
- Prolonged prothrombin time and activated partial thromboplastin time
- Increased D-Dimer
- Increased serum lactate dehydrogenase and creatinine phospho-kinase
- Hypoalbuminemia 4