People pushed the panic button when they heard Prime Minister Prayut Chan-o-cha warned two weeks ago that the spread of the influenza virus this year would be greater than the last. The virus forced two Bangkok schools, Chulalongkorn University Demonstration Elementary School and St Joseph Convent School, to close some parts of the premises for inspection and cleaning after students were found to have been infected.
Although the discontinued classes have resumed, the influenza virus -- or the influenza Type A virus to be precise -- still rings the alarm bell. Altogether, up to four schools in Bangkok and two more in the provinces had to be temporarily shut down to prevent the virus from spreading.
According to figures from the Bureau of Epidemiology under the Ministry of Public Health's Department of Disease Control, as of Feb 6, around 6,800 people across the country have been reported to have been infected with the influenza virus this year. Five provinces with the highest infection rate per 100,000 people are Lamphun, Chiang Mai, Patthalung, Bangkok and Surat Thani. When compared to the same period last year, more than 11,500 people were reported to have been infected with the flu virus from Jan 1 to Feb 15, 2016 -- almost double this year's infection rate. In the entire 2016, more than 167,200 were reported to have fallen victim to the virus, with 44 deaths.
To better understand the situation, here are six points worth taking note.
Speaking of the influenza A virus that is wrecking havoc right now, is it actually a new strain?
The influenza A virus that is spreading in Thailand at the moment is actually not new, said infectious medicine specialist Dr Samornrod Limmahakhun.
"It is just seasonal flu caused by the influenza A virus," she clarified.
According to the doctor, there are three major types of influenza viruses -- A, B and C. Influenza type C virus does not generally cause severe illnesses and is not considered epidemic prone.
The influenza A and B viruses are more common and responsible for most flu cases. The influenza A virus is divided into subtypes based on two proteins on the surface of the virus: the hemagglutinin (H) and the neuraminidase (N). The most widely-known subtypes of the influenza A virus are the H1N1 and H3N2.
According to data from the US Centers for Disease Control and Prevention (CDC), the influenza B virus is not divided into subtypes, but can be further broken down into lineages and strains. Currently there are two lineages -- B/Yamagata and B/Victoria.
Each of the influenza viruses has no specific epidemic patterns, added Dr Samornrod, unlike the dengue virus where large outbreaks mostly occur every two years. But in Thailand the influenza viruses usually spread during rainy season or from May until October and winter or from December to January.
What are the differences between symptoms of influenza and common cold?
One major difference is fever temperature, Dr Samornrod explained. The influenza viruses usually cause a fever of over 38-39C while the common cold's fever is not that high. The rest of the symptoms can be quite similar for flu and common cold -- coughing, headache, muscle pain, sore throat and runny nose.
If flu is suspected, a specialist might prescribe a flu test, which involves rubbing a cotton swab along the back of the throat or up the nose. This procedure is to collect respiratory specimens that will be sent out to the lab. However, this quick test has some limitations -- it can only screen 70% of influenza cases.
"If the test is positive, it is clear patient is infected with a flu virus," the specialist said. "But if the test turns out negative, the patient might not be infected or he/she might be infected but the test cannot detect the virus."
A more detailed and accurate test called PCR is available and it can detect 100% of influenza viruses. However, PCR is quite expensive when compared to the regular test. The quick test costs around 900 baht while the PCR can cost up to 4,000 baht.
People at a higher risk of developing severe flu symptoms including lung infection, respiratory failure and death are those aged over 60-65 years old, children less than two-years-old, pregnant women and people suffering underlying diseases like diabetes, heart diseases as well as kidney and liver diseases. In 2006, according to Dr Samornrod, it was found that a number of obese people died from catching the influenza viruses.
Is it always necessary to take medication to cure the virus?
"The flu can go away on its own but it takes time," the doctor said. Usually a fever will stay for no more than five days. If patients can take good care of themselves by resting and drinking enough water, the body will rid the virus without having to depend on antibiotics.
But it is important to note that taking medication would help fever go down faster and prevent the virus from spreading. The aforementioned high-risk groups should take medication so that the virus would not cause severe symptoms.
What about the flu vaccine? Is it true we can still get infected despite being vaccinated?
Each year, the flu vaccine will be produced with the vaccine viruses similar to the influenza viruses predicted by the World Health Organization (WHO) to circulate most commonly during the upcoming flu season. The prediction, said Dr Samornrod, is based on accumulated data and records as to which virus strains have caused trouble in the past.
The vaccine, which is in use right now, can protect against four flu strains -- two A strains and two B strains. Given the influenza A virus has so many subtypes, it is likely that one might get infected with the virus strain that is not covered by the vaccine.
"This is the reason why the vaccine has only 60-70% efficacy -- not 100%," she added. "But if you are vaccinated, there will be two scenarios. First, the vaccine might 100% prevent you from the virus or, second, it will alleviate the symptoms in case the vaccine does not cover the virus that infects you."
The flu vaccine is, however, recommended for anyone aged above six months. Those with severe allergies to egg, however, cannot get the injection because the ingredient is used during the manufacturing process of the vaccine. People who have fever should wait until they fully recover to receive a shot given it is the period when the body's immune system is already low and thus difficult to be stimulated for attack.
In Thailand, the best timing to get the vaccine, advised the infectious medicine specialist, is before rainy season. This is just before the influenza season begins in the country.
Should we just stay home after getting infected?
Most healthy adults may be able to infect others beginning one day before fever develops and up to five after becoming sick. This is called the contagious period during which the infected should avoid public places including schools and offices.
Any way to avoid getting the flu?
According to the WHO, the best way to avoid getting the virus is to get the flu vaccine every year. Influenza viruses evolve constantly. Twice a year the WHO makes recommendations to update the vaccine compositions. For the 2016-2017 northern hemisphere influenza season, the quadrivalent vaccine formulation was updated in February 2016 to contain two type A viruses (H1N1 and H3N2), and two type B viruses. For the southern hemisphere, the 2017 vaccine was recommended in September 2016 to contain H1N1 and H3N2 and two B viruses.
