Influenza and the Flu Vaccine 2024

Reviewed By: Dr Namrata Arora

What is Influenza?

Influenza or the flu is a contagious respiratory condition caused by the influenza virus (types A or B). Flu symptoms can range from mild to serious. It can present with respiratory symptoms such as cough, sore throat or runny nose. There are also often generalised symptoms like fevers or chills, body aches, fatigue and headaches.

Possible Complications

While most people recover from the flu in a few days to 2 weeks, some may develop complications. Sinus and ear infections can occur. More serious and potentially life-threatening complications include infection in the lungs (pneumonia), inflammation of the heart (myocarditis), brain (encephalitis) or muscle (myositis, rhabdomyolysis) tissues, and even multi-organ failure.

Those who are at higher risk of complications include the elderly, children, pregnant women and those with chronic medical conditions (like asthma, diabetes or heart disease).

Diagnosis and Treatment

It is difficult to differentiate influenza from other viral illnesses just by symptoms. Rapid influenza diagnostic tests or molecular assays in the lab (done with nasal swabs or throat swabs) can help with the diagnosis. In suitable cases, antiviral medication can be used to treat the condition.

Prevention and the Influenza Vaccine

Frequent hand washing and wearing masks are helpful in preventing the spread of respiratory viruses. However, the best way to prevent the flu is by getting vaccinated annually. The flu vaccine helps protect against the four influenza viruses that research indicates are most common during the upcoming season.

OT&P offers the quadrivalent flu vaccine injection and the live attenuated intranasal flu vaccine (Flumist) for suitable cases.

The flu vaccine can help prevent you from getting sick with the flu. If you do get sick, getting the vaccine reduces the severity of illness and lowers the risk of flu-associated hospitalisation. A 2021 study showed that among vaccinated patients who were admitted to the hospital with influenza, had a 26% lower risk of intensive care admissions and 31% low risk of death from flu compared to those who were unvaccinated.

The flu shot can be beneficial as a preventative tool for people with chronic health conditions. Even if you are healthy, getting the vaccine is an important way of protecting yourself and your loved ones who may be more vulnerable. During pregnancy, it helps protect pregnant women and after pregnancy it helps protect their infants from flu in their first few months of life.

According to the Scientific Committee on Vaccine Preventable, influenza activity in Hong Kong has remained low in the past 3 years due to COVID-19 and mask wearing. Therefore, immunity against influenza in Hong Kong may be relatively weaker than the past. Local influenza activity has started to increase since March 2023. As we enter the peak season of seasonal influenza, the risk of transmission will get higher and appropriate prevention is important. The Centers for Disease Control and Prevention (CDC) recommends that in the absence of contraindications, all persons aged 6 months or above should receive the influenza vaccine annually.

If you have any questions or concerns regarding the flu vaccine, consult your healthcare provider for personalised advice and support.

Reference

1. Centers for Disease Control and Prevention. (2023, June 30). Influenza (flu). Centers for Disease Control and Prevention. Retrieved August 18, 2023, from https://www.cdc.gov/flu/index.htm.
2. Centers for Disease Control and Prevention. (2022, September 13). What are the benefits of flu vaccination?. Centers for Disease Control and Prevention. Retrieved August 18, 2023, from https://www.cdc.gov/flu/prevent/vaccine-benefits.htm.
3. Recommendations on Seasonal Influenza Vaccination for the 2023-2024 Season in Hong Kong. Scientific committee on Vaccine Preventable Diseases. (n.d.). Retrieved August 18, 2023, from https://www.chp.gov.hk/files/pdf/recommendations_on_seasonal_influenza_vaccination_for_the_2023_24_season_in_hong_kong_19apr.pdf.