Influenza and symptoms

Flu, also called influenza, is a contagious infection of the nose, throat and lungs, which are part of the respiratory system. Flu is caused by a virus and people tend to often recover on their own. Flu can cause mild to severe illness, and at times can lead to death. Flu symptoms usually come on suddenly. In a typical flu season in the U.S., it’s estimated that between 20,000 and 50,000 people die from the flu. Another 300,000 to 500,000 require hospitalization for serious illness. 

What are the types of flu? 

Influenza A & B mostly commonly infect people during winter and have more severe symptoms. Influenza C doesn’t cause severe symptoms and it’s not seasonal — the number of cases stays about the same throughout the year. H1N1 (swine flu) and bird flu are both subtypes of influenza A. (https://my.clevelandclinic.org/health/diseases/4335-influenza-flu) 

People who have flu often feel some or all of these signs and symptoms:

• Fever or feeling feverish/chills
• Cough
• Sore throat
• Runny or stuffy nose
• Muscle or body aches
• Headaches
• Fatigue (tiredness)
• Some people may have vomiting and diarrhea, though this is more common in children than adults.

Cold vs flu symptoms

(https://www.cdc.gov/flu/signs-symptoms/index.html) 

Risk factors of getting flu: 

• Children under 2 years or older adults over 65 years.
• Weakened immune system or people on immunosuppressant therapy.
• Chronic illness for e.g. asthma, COPD, kidney , liver or heart disease, diabetes, stroke. 
• Young people on long-term aspirin therapy are at risk of developing Reye's syndrome if infected with the influenza virus.
• Pregnant people are more likely to develop influenza complications, particularly in the second and third trimesters.
• People with a body mass index (BMI) of 40 or higher have an increased risk of flu complications. (https://www.mayoclinic.org/diseases-conditions/flu/symptoms-causes/syc-20351719) 

People in crowded places like nursing homes or school going children are more prone to catching flu.

Seek immediate medical attention if the symptoms include: 

• High fever (over 103 F/40 C).
• Difficulty breathing.
• Not peeing or peeing very little.
• Pain in chest or stomach (abdomen) that doesn’t go away.
• Persistent dizziness or confusion.
• Severe muscle pain or weakness.
• Seizures.
• Bluish skin, lips or nails (cyanosis, which can be a sign of low oxygen level in blood or tissues).
• Fever or cough that gets better or goes away but then get worse.

Worsening of other health conditions. (https://my.clevelandclinic.org/health/diseases/4335-influenza-flu)