Health alert: H3N2 outbreak

Those with chronic health conditions such as dia?betes, asthma or heart conditions as well as the young, the elderly and pregnant women are generally more likely to suffer from complications. Influenza is not a con?dition to be taken lightly. When the flu attacks high-risk populations, it is estimat?ed that the illness is a contributing factor to anywhere between 3,000 to 49,000 deaths per year in the United States alone.
Influenza spreads through contaminated water droplets that pass from person to person. When an infected person sneezes, coughs, and speaks the virus travels in the water droplets to an unsuspecting new per?son and enters through their nose or mouth. Although not as common, the flu can also be transmitted after touching a contaminated surface with your hands and then rubbing your eyes, mouth, and/or nose. An infected person is contagious a day before he or she becomes sympto?matic and continues to be contagious for about a week thereafter.
Influenza in Thailand can be transmitted throughout every season. However, the rainy season usually sees the highest transmission
Organisations such as the World Health Organisation are constantly tracking the viruses that cause the flu all over the world. Based on their findings they deter?mine which viruses will most likely cause influenza during the coming year and rec?ommend what the flu vaccine most like to protect. Therefore, from one year to the next the flu vac?cine is different. The leading cause of influen?za cases this season is due to the influenza A H3N2 virus (74 per cent). H3N2 is a subtype of influenza A (sim?ilar to H1N1 commonly referred to as “swine flu”).
As the flu vac?cine composi?tion changes year to year and immunity (the body’s ability to make antibodies against the virus) declines over time, it is recommended that individuals receive the flu vaccine annually. The flu vaccine this year covers against the following influenza viruses:
- A/California/7/2009 (H1N1)pdm09-like virus;
- A/Victoria/361/2011 (H3N2)-like virus;
- B/Wisconsin/1/2010-like virus (from the B/Yamagata lineage of viruses).
Therefore, the best way to protect your?self and those you love from influenza A H3N2 virus, as well as the other two lead?ing influenza viruses, is by being vaccinat?ed. However, one must keep in mind that no vaccine works 100 per cent of the time. In the past the flu vaccine has been shown to be approximately 70 per cent effective across age groups, being most effective among healthy adults and older children.
Side effects to the vaccine include a low-grade fever, general aches, and soreness at the injection site. These symptoms last approximately two days and over the counter pain relievers such as acetamino?phen can provide relief.
Some individuals should not receive the vaccine. They include:
- Individuals with a severe allergy to eggs
- Individuals with a history of Guillain–Barr? Syndrome
- Individuals who are presently suffering from an illness causing a high fever
- Children less than six months of age
Antibiotics treat bacterial infections and antiviral medications can be used to treat the viruses that cause the flu. Antiviral medications work the best if taken within two days of having symptoms. They short?en the duration of illness by one to two days and help prevent serious complica?tions from developing. The antiviral med?ications recommended for this year include: Tamiflu (generic name oseltamivir) and Relenza (generic name zanamivir) and they are usually taken for five days.
Individuals who have had the flu in the past know it is no picnic and can drag on for up to two weeks. The flu vaccine available this year is known to be a good match to the H3N2 virus causing the majority of the flu cases this season and it is strongly recommended.

Dr Krirk Asavametha is an infectious diseases specialist with Samitivej Sukhumvit Hospital. Call (02) 711 8484-5.