By Dr. Ekaterina (Kate) Naumova*

Most people have had the flu, but not everyone knows that the word “influenza” refers to a very specific group of viruses that are a dangerous subset of the various common colds and flus we’re familiar with. In Việt Nam, you can get it at any time of the year.

Influenza is a serious respiratory infection that can result in hospitalisation and even death. The most common complication of influenza is bacterial pneumonia, but it can also aggravate chronic diseases such as asthma, chronic rhinitis and diabetes. It’s a highly contagious viral infection transmitted by coughing, sneezing or contact with someone who is infected, and it can also be transmitted if you touch surfaces on which infected influenza droplets have landed.

After being exposed, it usually takes an average of two days to develop symptoms, but it can range from one to four days. Typical influenza disease causes the onset of fever, headache, a runny or stuffy nose, eye pain and sensitivity to light. Kids may also suffer from nausea, vomiting and diarrhoea.

The fact that it spreads so easily is what makes it such an important health problem. People become contagious from the very beginning, one or two days before the onset of symptoms – even when they don’t yet know they have it. You can still pass on the virus to others for the next four or five days after the onset of symptoms.

Once you’re infected, there’s no going back. The virus will collect in the upper respiratory tract, producing phlegm in the airway in response to the inflammation of the surrounding organs. Your immune system (provided it’s functioning normally) will start to detect the presence of the virus multiplying in your body, and get to work on developing an antibody to fight it. The symptoms you experience are a combination of the spread of the virus and your body’s countermeasures, which will cause inflammation, fever and discomfort. Once your body has produced these antibodies, you’ll be protected from reinfection – and if you ever do contact the same virus again, it will be swiftly and invisibly dealt with.

So how is it that you can get the flu again and again? It’s because influenza gradually morphs into different forms as it spreads, making it resistant to antibodies that worked against it before. This means that every time the body catches a new strain of influenza, it must start from the beginning.

How can people protect themselves from a shape-shifting disease that keeps turning out new forms to infect us again and again? Firstly, we can try our best not to put ourselves and others at risk in the first place. For a start, remember to cover your nose and mouth with your sleeve or a tissue when you cough or sneeze. Wash your hands often with soap and water, or at least alcohol-based hand cleansers. Stay away from people who are sick as much as possible. If you already have influenza, stay at home from work or school for at least 24 hours after the fever has ended.

The best way to prevent influenza is vaccination. Because the strains of viruses change every year, pharmaceutical companies conduct research to find out which strains will be typical for the coming season worldwide. According to their results, they produce a new vaccine to match the circulating strains. Every year, we receive new vaccines that are different from the older ones and more effective against the forms of influenza that are likely to be ascendant during the following twelve months.

We usually receive our annual vaccines in October, which is the best time to get vaccinated. We use an inactivated vaccine (made from killed viruses) produced by Influvac that doesn’t cause the disease. Unlike some vaccines, Influvac does not contain egg, meaning those with egg allergies (including pregnant women) can take it safely. It will protect you only from the more common strains of the influenza virus, however—if you’re unlucky, you could still contract a less prevalent strain.

People aged six months and older should get the influenza vaccine, unless they suffer from an immunodeficiency condition. Kids under six months old should not get vaccinated because they’re too small—usually at that age, however, the mother is breastfeeding, so she can pass on some immunity to the baby if she is vaccinated. It’s recommended that everyone in a family with a baby should get vaccinated while the baby is still too young to receive or develop its own antibodies. It’s also important to note that kids under eight years old who receive their first-ever flu vaccine should get two shots one month apart to fully trigger their immune response.

The 2019-20 influenza vaccination contains the following:

• A/Michigan/45/2015 (H1N1)pdm09-like strain
• A/Kansas/14/2017 (H3N2)-like strain
• B/Colorado/06/2017-like strain. — Family Medical Practice

*Dr. Ekaterina (Kate) Naumova gravitated toward pediatrics early in her career, drawn by a love for children, moving on to pursue her interest in dietetics and enhancing people's health through nutritional changes. She is a graduate of the Pirogov Russian National Research Medical University.

Family Medical Practice was the first foreign-owned primary healthcare provider in Việt Nam, and has consistently remained at the forefront of international-standard medicine since 1995. It offers extensive healthcare and emergency medical services nationwide to Vietnamese, expatriate and corporate customers.

For more advice on any medical topics, visit Family Medical Practice Hanoi at: 298 I Kim Mã, Ba Đình. Tel: (024) 3843 0748.  E: hanoi@vietnammedicalpractice.com.

FMP’s downtown Hồ Chí Minh location is: Diamond Plaza, 34 Lê Duẩn, District 1; 95 Thảo Điền, District 2. Tel: (028) 38227848. E: hcmc@vietnammedicalpractice.com

FMP Đà Nẵng is located at 96-98 Nguyễn Văn Linh, Hải Châu District, Đà Nẵng. Tel: (0236) 3582 699. E: danang@vietnammedicalpractice.com