KUALA LUMPUR – Influenza or flu may be a commonly-occurring respiratory tract infection in Malaysia but its severity should not be underestimated.
University of Malaya Medical Centre visiting senior clinical consultant Dr Yasmin Abdul Malek said this was because influenza could lead to respiratory, cardiovascular and nervous system complications.
Based on serosurveillance (which is an important component of any comprehensive surveillance system for vaccine-preventable diseases) using molecular tests, influenza is detected in 13 per cent of respiratory samples from patients with Influenza-like illness.
According to Yasmin, one study also showed that between 2008 and 2010, the seroprevalence rate (or level of a pathogen such as virus or other microorganisms in a population as measured in blood serum) for Influenza A H1N1 was 22.3 per cent and Influenza A H3N2, 14.7 per cent.
“Despite its familiar presence (in Malaysia, the severity of the flu should not be underestimated, particularly if we fall into one of the more vulnerable patient profiles.
“Even if not hospitalised, an influenza-infected person can subsequently develop serious complications like a heart attack or stroke,” she said.
Respiratory complications arising out of influenza include sinusitis, pneumonia and bronchitis; cardiovascular complications include heart failure and increased risk of heart attack; and nervous system complications include Reye’s syndrome (a rare but serious condition that causes swelling in the liver and brain in children), acute viral encephalitis (also in children) and Guillain-Barre syndrome (an autoimmune disorder).
INFLUENZA BURDEN IN CHILDREN
Yasmin said the highest risk of complications occur among pregnant women, children aged between six and 59 months, senior citizens aged over 65, those with weakened immune systems, those with specific medical conditions such as asthma and chronic heart or lung diseases, and healthcare workers.
She pointed out that 50 per cent of those infected with influenza usually do not show any symptoms and, thus unknowingly spread the disease to others.
“So, if we are to fall within this 50 per cent, yes, we are fine, but we are the ones who will spread the virus to others like our children or grandparents who then become ill,” said Yasmin, who is also a part-time lecturer at the Medical Microbiology Department at Universiti Malaya’s Faculty of Medicine.
Flu outbreaks among schoolchildren are common in this country.
“They (schoolchildren) have the highest influenza attack rates during inter-pandemic periods. And, in an epidemic, they develop the disease earlier than other age groups,” she said, adding that children were also at greater risk of transmitting influenza within communities than adults.
Citing the findings of a small local study of 132 children who were hospitalised for influenza in Kuala Lumpur from 2002 to 2007, Yasmin said 16 of them had severe influenza requiring intensive care or ventilation. Nine of these 16 patients were previously healthy.
There were three deaths and among those who died was one who was previously healthy with no underlying chronic illness.
Globally, a report by the World Health Organisation (WHO) stated that in 2008, there were an estimated 28,000 to 111,500 deaths in children under the age of five due to influenza-associated acute lower respiratory infections. According to WHO, 99 per cent of these cases occurred in developing countries.
PREVENTION IS BETTER THAN CURE
Yasmin said with the availability of flu vaccines, the risk of developing influenza-related complications can be reduced.
In fact, WHO recommends annual vaccinations for high-risk individuals, including pregnant women, children aged between six months and five years and individuals aged over 65, as well as those with chronic medical conditions and healthcare workers.
“Not only do you protect yourself but also your community and, more importantly, your loved ones as we all know that Malaysians love to hug and kiss their grandchildren. Close contact is part and parcel of our culture,” said Yasmin.
She said adults who are vaccinated against the flu can help to protect infants under three years who cannot yet be vaccinated.
Flu vaccines cause antibodies to develop in the body about two weeks after vaccination. These antibodies provide protection against infection with the viruses that are in the vaccine.
Currently, there are two categories of vaccines available, namely the trivalent inactivated vaccine (TIV) that contains two Influenza A strains and one Influenza B strain; the second one is quadrivalent influenza vaccine (QIV) that includes two Influenza A strains and two Influenza B strains.
Recently, GlaxoSmithKline Pharmaceutical Sdn Bhd introduced Fluarix Tetra, an inactivated QIV, indicated to protect adults and children over three years old.
Influenza or flu is a contagious respiratory illness caused by viruses that infect the nose, throat and lungs.
There are three types of influenza, namely Influenza A, B and C.
Type A and B cause the annual influenza epidemics that affect approximately five to 10 per cent of adults and 20 to 30 per cent of children every year across the world.
Unlike the common cold – the symptoms of which include runny or stuffy nose – influenza symptoms also manifest throughout the whole body in the form of fever, cough, sore throat, muscle or body aches, headache and fatigue.
An adult infected with the virus may be contagious from day one before symptoms start right up to five to seven days after becoming sick.
Meanwhile, children may continue to transmit the virus for up to seven days upon contracting the infection.
Influenza viruses are airborne and mainly spread through the droplets produced when someone with the flu coughs, sneezes, or has close contact with others.
In Malaysia, influenza occurs throughout the year with no seasonal trends.- BERNAMA