How does a flu nasal spray work?
Flu nasal sprays, also known as live attenuated influenza vaccines (LAIVs), work by introducing a weakened form of the influenza virus directly into the nose. This allows the body to develop immunity against the virus without causing the actual flu illness. Here's how a flu nasal spray works:
1. Administering the Spray: The flu nasal spray is administered by gently spraying a small amount of the vaccine into one or both nostrils, as directed by a healthcare professional.
2. Introduction of the Weakened Virus: The nasal spray contains a live, but weakened form of the influenza virus. These viruses have been carefully selected and attenuated, meaning they have been modified to be unable to cause the flu.
3. Replication in the Nose: Once in the nose, the weakened viruses begin to replicate within the nasal cells. This process mimics a natural infection, but since the viruses are attenuated, they do not cause any significant symptoms of the flu.
4. Immune Response: The replication of the weakened viruses stimulates the immune system to respond. The body recognizes the viral proteins as foreign and starts producing antibodies against them. This process is crucial in developing immunity against the influenza virus.
5. Nasal Immunity: The nasal spray induces local immunity within the nasal passages, where the flu virus typically enters the body. The antibodies produced in the nasal mucosa can help neutralize and prevent the live influenza viruses from establishing an infection in the nose and spreading further into the respiratory tract.
6. Systemic Immunity: In addition to local immunity, the nasal spray also contributes to systemic immunity. Some immune cells that encounter the weakened virus in the nose can travel to other parts of the body and stimulate the immune system to produce antibodies that circulate throughout the bloodstream. This systemic immune response helps protect the body against the flu even if the virus enters through other points of entry.
7. Duration of Protection: Flu nasal sprays typically provide protection for the influenza season, which usually runs from fall to spring in the Northern Hemisphere. However, the effectiveness of the spray can vary based on individual immune responses and the circulating strains of influenza viruses.
It's important to note that flu nasal sprays are contraindicated for certain individuals, such as those with a weakened immune system or certain medical conditions. It's always best to consult with a healthcare professional before opting for a flu nasal spray or any other type of flu vaccine to ensure it's the most appropriate choice based on individual circumstances and health status.