Is it the flu or just a cold?
With flu season just around the corner, it's time to start thinking about that annual jab
Flu – that contagious respiratory illness caused by a virus – is common to just about every country, with most of the annual outbreaks occurring just once a year during the winter.
Not so in Thailand: As in other tropical countries, flu hits twice a year – from January to March and then again in the rainy season from June to August. Experts are judging the likely severity of this rainy season outbreak based on reported cases from January to March and this year, there were some 40,000 cases of flu and three deaths attributable to the virus.
“The figures shows that the outbreak will probably be worse than last year,” says Assoc Prof Dr Tawee Chotpitayasunondh, president of Paediatric Infectious Disease Society of Thailand.
For most people, differentiating between the common cold and influenza can be difficult. Most stay at home and take over-the-counter medicines until they feel as though they’ve recovered. But how do you know when you should see a doctor?
The best way, Dr Tawee says, is to observe the symptoms, and if you have high fever for two consecutive days, then it’s time to visit a doctor. Initially, the flu may seem like a common cold with fever of over 38 degrees Celsius, aching muscles, chills and sweats, headache, cough and sore throat.
A high fever means that your body temperature is over 38 degrees with peaks once a day. The length of the peak, Dr Tawee adds, depends on your own defence mechanism.
The World Health Organisation reports that around one billion people are infected with the flu every year, with around 3-5 million patients requiring hospitalisation and 500,000 people dying from complications. As the influenza virus lives longer in cold weather, outbreaks happen in the cold season.
“Aside from the cold weather factor, in Thailand, the peak is also in the rainy season. That’s because schools have reopened after the long summer break and children, who are a high risk group, tend to spread the virus,” says Dr Tawee.
For most people, influenza is a mild illness that resolves on its own. But sometimes, influenza and its complications can be deadly. People at higher risk of developing flu complications include young children, the elderly, pregnant women, people who have asthma, heart disease, kidney disease and diabetes, and people who suffer from chronic illnesses.
The mortality rate in Thailand is one in every 10,000 populations and worsens to one in every 1,000 population when a pandemic hits, like it did in 2009.
Unlike bacteria that can be cured by antibiotics, there is no medicine to kill a virus. A virus initiates infection by attaching to its specific receptor on the surface of a susceptible host cell. That means medication to block the virus is not able to attach the receptor.
“The influenza virus is different from other viral diseases as it is highly transmittable, preventable and treatable. We have a vaccine and the medication oseltamivir phosphate eases the symptoms and helps patients get better one or two day |quicker than if they didn’t take it,” says Dr Tawee.
In Thailand, oseltamivir, which has been used for more than a decade, is available only at hospitals to prevent overuse. Doctors make the diagnosis through symptoms and confirmatory lab tests before prescribing the medicine, which must be taken twice a day for five consecutive days.
Now a new drug called baloxavir is available and has just been approved by the Food and Drug Administration. Thailand is the third country to sign off on the drug and the first to approve its use for patients in high-risk groups.
Instead of taking it five consecutive days like oseltamivir, patients take a single pill in one dose. It’s expected to cost Bt1,000 per pill.
There are three types of influenza – A, B and C – and each has a variety of subtypes. Of these, type A, which includes the subtypes H1N1 and bird flu H5N1, and type B (Victoria and Yamagata) are responsible for annual influenza epidemics. Type C, while it can lead to flu, is mostly harmless. But influenza viruses are constantly mutating and new strains appear regularly. For more than 50 years the World Health Organisation has collaborated with scientists and policy makers on a global scale to develop a unified approach to manufacturing, testing and regulatory oversight of influenza vaccine development as well as their efficient use and distribution.
WHO updates the prevalence of the outbreak for the upcoming year, seeing which type or subtype of virus will cause the outbreak and then sending the information for the pharmaceutical company to produce the vaccine.
The vaccine production process takes six months to complete. In some years, the vaccine is less effective either because the virus has drastically mutated during the timeline or the prediction is incorrect. “That’s why you have to get a vaccine every year,” says Dr Tawee.
In Thailand, the new annual vaccine will be out sometime this month. The virus type on which it is based will be the same as that produced for countries in the southern hemisphere, where the outbreak coincides with Thailand’s rainy season. Dr Tawee advises getting it as soon as it comes out, saying, “It’s better to keep the vaccine in our body than in the refrigerator.”