Understanding the Nasal Spray Influenza Vaccine: An Alternative Prevention Option and Who It Suits

Getting an influenza vaccine is one way to prevent and reduce the risk of severe complications from the flu. Besides the injection, there is also a nasal spray influenza vaccine. What are its pros and cons, and who is it suitable for?

What is the nasal spray influenza vaccine?

The nasal spray influenza vaccine (Live Attenuated Influenza Vaccine: LAIV) was developed to provide convenience and build immunity without the pain of traditional injections. It has the following advantages and disadvantages.

Advantages of the nasal spray influenza vaccine

• Needle-free: administered by spraying into the nasal cavity, making it friendly for children and those afraid of injections.
• Highly effective in children: studies have shown it can reduce the chance of influenza infection in children by up to 88%.
• Reduces disease severity: even if infection occurs, the vaccine helps lower the chance of hospitalization by over 60%.
• Safe and widely used globally: this vaccine has been used for more than 20 years and is recommended as a first choice for children aged 2–17 in many countries.

Disadvantages of the nasal spray influenza vaccine

• Higher cost: generally more expensive than the injectable vaccine.
• More health restrictions: as it is a "live attenuated" vaccine, there are more groups who cannot receive it compared to the injection.
• Localized side effects: may cause nasal congestion, runny nose, or sore throat more often than the injectable vaccine.

Who is suitable for the nasal spray influenza vaccine?

• Children and adults aged 2–49 years.
• Those who dislike injections or fear needles.
• Those seeking a safe, painless vaccination option.

Who should be cautious about the nasal spray influenza vaccine?

• Children under 2 years old and adults aged 50 and above.
• Pregnant women.
• People with weakened immune systems, such as those with HIV, on immunosuppressive drugs, or cancer patients.
• Individuals with certain chronic conditions, like severe asthma (with wheezing in the past 12 months) or heart disease.
• Those in close contact with severely immunocompromised patients, as the vaccine virus might slightly spread to them.

Possible side effects from the nasal spray vaccine

The nasal spray vaccine is generally very safe, but some may experience mild side effects such as nasal congestion, runny nose, or low-grade fever. These symptoms are usually mild and resolve within 1–3 days.

Why should you get an influenza vaccine every year?

Influenza viruses continuously change strains. Annual vaccination, whether by injection or nasal spray, is important to ensure the body’s immunity matches the circulating virus that year. The nasal spray influenza vaccine (LAIV) is another suitable option for people aged 2–49, especially children and adolescents. Its benefits include needle-free administration, immunity at the virus entry point, and high effectiveness in reducing infection rates and disease severity, comparable to injectable vaccines.

Information provided by Dr. Surawat Homwiset, Pediatric Allergist and Immunologist, Vejthani International Hospital.