Doctor, I have flu…

Is it really “flu”?

Many patients in Singapore use the term “flu” to describe a variety of symptoms such as running nose, fever and cough. Physicians usually diagnose most of these conditions as acute upper respiratory tract infections (URTI). URTI are caused by a variety of pathogens, mostly viral.

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The term “flu” should refer more specifically to influenza. Influenza is a viral infection that affects mainly the nose, throat, bronchi, and occasionally, the lungs. Infection is characterised by high fever, chills, sore throat, cough, headache, muscle ache, nasal discharge, and fatigue. It may be difficult to differentiate influenza from other URTI clinically. However, it is important to note that influenza infections may lead to serious complications such as pneumonia, ear infection, and meningitis1 2.

Influenza is not always a mild disease.

Influenza in Singapore

While there is ongoing influenza transmission in the community throughout the year, Singapore has two main influenza seasons, from December to February, and from May to July, corresponding approximately to the northern and southern hemisphere winters.

In Singapore, influenza-associated hospitalisation has been estimated to be 29.6 per 100000 persons each year, or about 1500 hospitalisations per year. The elderly and children had much higher rates of hospitalisation. Hospitalisation rates for persons >75 years of age and children <6 months of age were 47 times and 26 times higher, respectively, than those for persons 25–44 years of age3. An earlier study had estimated that influenza caused 588 deaths in Singapore annually4.

Have you been vaccinated?

Influenza vaccine provides good protection against influenza infection and its complications. Annual vaccination is recommended, especially for individuals at higher risk of developing complications from influenza infections. These individuals include5:

  • persons aged 65 years and older,
  • children aged 6 months to less than 5 years (i.e. 59 months), adults and children who have chronic disorders of the lung  or heart systems, including asthma
  • adults and children who have required regular medical follow-up or hospitalisation during the preceding year due to chronic metabolic diseases (including diabetes mellitus), renal, neurologic, liver, or blood disorders, or immunosuppression (including immunosuppression caused by medications or the Human Immunodeficiency Virus);
  • children and adolescents aged 6 months to 18 years who are receiving long-term aspirin therapy and therefore might be at risk for developing Reye syndrome after influenza infection;
  • women at all stages of pregnancy;
  • residents of nursing homes and intermediate and long term care facilities;

The uptake of influenza vaccination in Singapore is low. In the 2012 Health Behaviour Surveillance of Singapore, only 8.7% of adults aged 50–69 years reported having been vaccinated against influenza3.

The new Southern Hemisphere vaccine which has been released in May 2015 protects against the current circulating strains of influenza. It covers all 3 common strains of influenza i.e. influenza A/H1N1, A/H3N2, and influenza B.

Do visit your healthcare provider to enquire about influenza vaccination, and get your flu shot today!

References

  1. World Health Organization (WHO), Influenza, March 2015; Accessed on 12 June 2015.
  2. Health Promotion Board (HPB), Singapore, Essential Facts on Influenza, 2 March 2015; Accessed on 12 June 2015.
  3. Ang, et al. (2014). Influenza-Associated Hospitalizations, Singapore, 2004–2008 and 2010–2012; Accessed on 12 June 2015.
  4. Chow, et al. (2006). Influenza-associated Deaths in Tropical Singapore; Accessed on 12 June 2015.
  5. Ministry of Health (MOH), Singapore, Influenza; Accessed on 12 June 2015.