What is flu and why should we get vaccinated?
Seasonal influenza is a viral illness causing outbreaks every year. It is a common illness causing acute respiratory symptoms, lethargy, pain and fever. It often results in loss of school and work days. In most children and adults, it is a self-limiting illness, however it can sometimes cause severe symptoms leading to hospitalisation with complications such as pneumonia and even death. In Hong Kong it is more common in the winter months, mainly from January to March, and there is also a small peak in July and August.
The best way to prevent influenza and reduce the symptoms is by having vaccination every year, in addition to practising good personal hygiene and healthy lifestyle.
Who should be vaccinated?
Everyone 6 months of age and over should have a flu shot every year. People who are at high risk of developing complications should be given priority. Children younger than 5, adults over 65 years of age, pregnant women, smokers, frequent travellers, health workers, people with chronic conditions such as asthma, heart diseases, diabetes, immunosuppression, neurological disorders, cancers and extreme obesity, are prone to have more severe influenza and complications.
What are in the flu vaccines?
The World Health Organisation (WHO) offers recommendations for strains of flu viruses to be included in the vaccine each year. For the 2016-2017, A/California/07/2009(H1N1), A/Hong Kong/4801/2014 (H3N2), B/Phuket/3073/2013 and B/Brisbane/60/2008 are included in the quadrivalent influenza vaccine.
Injectable influenza vaccines are recommended during 2016-2017. The CDC stated that the nasal spray flu vaccine (live attenuated influenza vaccine) should not be used during 2016-2017.
There could be a trace amount of mercury in Thimerosal which is a common preservative in the flu vaccines. You could ask your health provider for a flu vaccine without Thimerosal.
It takes about 2 weeks after the injection for the vaccine to work.
Who should not have the flu shot?
They are infants who are less than 6 months old, people who had a severe allergic reaction to a flu shot in the past, individuals who had Guillain-Barre Syndrome (a paralysing immune disease) and very ill patients. People with a history of egg allergy should discuss with your doctor before having the shots as the vaccine is derived from an egg-based technology.
What are the side effects?
Most people suffer little or no side effects. The common side effects are runny nose, headache, body aches, mild fever and injection site redness and soreness. Severe side effects are very rare, they include hives, swelling and difficulty with breathing which should warrant immediate medical attention.
Article written by Dr Christie Chan Metcalfe.
Specialist in Family Medicine.
MBChB (Aberdeen) FHKCFP FRACGP FHKAM (Family Medicine)
DRCOG DCH (Ireland) DPD (Cardiff)
Optimal Family Health Limited