Flu Season: How Long Does the Transmission Period Last? 

Flu Season: How Long Does the Transmission Period Last? 

In the US, influenza cases occur year-round, but flu season occurs mainly between October and May. The peak of the flu season is typically between December and February, according to the Centers for Disease Control and Prevention (CDC), which has been tracking flu rates for 38 years. The CDC compiles records of the numbers, severity, and variants. BASS Urgent Care wants to share this information to keep you informed about seasonal flu.

History of the Vaccine

The influenza vaccine was developed to help protect against infection by flu viruses.  It was invented in 1945 and is distributed bi-annually to protect the US from an outbreak of influenza. Twice a year, the composition of the dosage is modified in anticipation of the mutation of the flu strain expected for that period. Some vaccines are more successful than others, but all versions have rendered modest to excellent containment results. Two hundred million doses are being produced for distribution this year.     

Variants of the Flu Virus

According to the CDC, there are 4 strains of the flu: A, B, C, and D. Type A is the primary cause of flu epidemics and is constantly changing. Influenza type A has 29 subtypes. These are classified by the proteins involved and divided into H and N divisions. This change makes the classifications difficult to calculate and modification of the vaccine is not easy.  

Influenza B viruses are less common but also affect humans. Like Type A, type B is categorized by different strains. C viruses are usually responsible for milder respiratory disorders but not epidemics. Flu vaccines do not address these minor illnesses. Influenza D mainly affects cattle, seldom humans.

Infection Signs and Symptoms

The symptoms of seasonal flu usually appear from 1 to 4 days after exposure to the virus. The flu can be transmitted by kissing, sharing a drink with an infected individual, or even touching an infected person. It can also spread by touching a surface that is contaminated. The most common way the flu virus spreads is through the air. Someone who is infected may cough or sneeze, then someone else inhales the airborne respiratory droplets. For those who are vaccinated as well as most healthy people, seasonal flu is a short-term, minor respiratory illness. It normally resolves itself when the immune system fights it off in about 5 to 7 days. Normal symptoms include:

  • Runny nose
  • Cough, congestion
  • Muscle aches
  • Chills
  • Fever 
  • Headaches
  • Fatigue

These symptoms are usually treatable with over-the-counter cold and pain medications and anti-inflammatories. Drink plenty of fluids to avoid dehydration. Give your body some time to battle the flu virus and recuperate. If these symptoms become severe, or you develop any of these additional complaints, consult a physician.

  • Fever over 101
  • Dehydration, inability to urinate
  • Nausea, vomiting
  • Diarrhea
  • Confusion
  • Respiratory Distress
  • Chest pain or tightness
  • Seizures

If you have severe symptoms, there are some antiviral medications that the physician can prescribe for you. These will help you get through the flu quicker and hopefully relieve some of your symptoms. 

More than 3 million flu cases have been reported in the US per year for the previous several years. The number of deaths from seasonal flu has been declining in recent years. The 2020-2021 numbers may be skewed due to the COVID-19 epidemic. Experts believe flu immunizations are the reason for the steady decline from 2018 to 2019. If you are unvaccinated and believe you have been exposed to the flu virus, please isolate yourself from others for a week to avoid spreading the disease. You may spread it to a vulnerable person and make them very sick or worse. Our experts at BASS Urgent Care recommend you take care of yourself and those around you this flu season. Contact us at 925.329.3718 to schedule your appointment or if you have any questions.