A senior citizen receiving the influenza vaccine administered by staff nurse Azma Suhainiza at the Klinik Kesihatan Kuala Lumpur . —AZHAR MAHFOF/The Star
PETALING JAYA: Influenza happens all year round in Malaysia, but it's likely that more cases occur in January and July compared with other months.
These two months recorded the highest positive rate for influenza samples tested in Malaysia over the past three years, according to data from the World Health Organization (WHO).
However, experts say such peaks are less distinct than those in temperate zones like Europe, Japan and New Zealand.
“Although it is possible for tropical countries like Malaysia to have increased incidence of influenza during certain months, these peaks are less pronounced as there is no distinctly cold season in Malaysia,” said epidemiologist Datuk Dr Awang Bulgiba Awang Mahmud.
He said in temperate countries, influenza tends to occur in the colder months.
“During the colder months, people tend to congregate indoors, the temperatures and humidity are lower and there are likely to have been some changes in the virus itself.
“These factors tend to favour survival and transmission of the virus which leads to peaks in those colder months,” he said.
Virologist Dr Jasmine E. Khairat said influenza cases often peak in January for temperate regions in the northern hemisphere and July for those in the southern hemisphere.
“In tropical climates like Malaysia, while there may be some peaks, influenza can circulate more consistently throughout the year.
“But rainfall patterns and humidity can also influence the timing of peaks,” said Dr Jasmine, who is a senior lecturer at the Institute of Biological Sciences at Universiti Malaya.
Click the arrow buttons below to see the influenza trends in Malaysia from 2022 to January this year:
In Malaysia, it was reported that the demand for flu vaccines spiked following news of the death of Taiwanese actress Barbie Hsu, 48, from a flu in Japan recently.
On Feb 10, Health Minister Datuk Seri Dr Dzulkefly Ahmad announced the expansion of the Influenza Immunisation Programme, which was launched in 2006.
As a result, the programme will cover not only frontline healthcare workers but also senior citizens aged 60 and above with at least one chronic illness.
On Feb 18, the voluntary vaccination drive began - a move that would benefit over 170,000 high-risk senior citizens, who can make appointments through the MySejahtera app.
Is it A or B?
Currently, there are two types of influenza viruses in Malaysia: Influenza A with its subtypes, and Influenza B.
Both types of influenza took turns to be the most common type in Malaysia at different times, based on data from WHO.
Influenza B was dominant in late 2022 to early 2023, but has since been overtaken by Influenza A until today.
As of Jan 27, Influenza A and its subtypes made up 71.8% of the positive influenza samples in Malaysia.
While influenza dominance changes, Dr Jasmine said influenza A was typically more prevalent.
She said past seasons, like 2016 and 2022, have seen influenza B dominate, but this was less common.
“This change among flu strains is a natural part of how these viruses evolve.
“One reason is because influenza A mutates faster, evading immunity from past infections or vaccines.
“This creates competition: the strain best at spreading and finding susceptible people persists,” Dr Jasmine explained.
Another factor was population immunity at a certain time.
“If many are immune to one strain (either by past infections or vaccination), another strain can take over against which the population has less immunity, to become more prevalent,” she said.
Dr Awang Bulgiba said Influenza A and B virus types tend to co-circulate so it is quite possible to see both types at the same time, which is what Malaysia is facing now.
See the graphic below to know more about each influenza type:
Annual flu jabs for all?
In future, experts believe that annual flu jabs will likely be a norm for many Malaysians.
Describing it as a good thing, Dr Jasmine said demand will likely rise as public awareness increases and the benefits of vaccination are better understood.
“I hope accessible vaccination programmes will play a vital role in making this a reality,” she said.
Dr Awang Bulgiba said Malaysia’s population was ageing and as a result, disease patterns will change.
“With ageing comes increased risks of chronic diseases like diabetes, which increases the vulnerability of individuals to infections like influenza.
“The provision of free flu jabs for seniors will provide an incentive for seniors to better protect themselves against influenza and therefore reduce the incidence of serious cases of influenza,” he said.
As such, he said annual flu jabs will become more common and hopefully lessen the burden on healthcare services as fewer people will fall ill or have serious illnesses due to influenza.
At present, it is a common practice for many travellers to get influenza shots before going abroad.
Here’s a list of the peak influenza positive rates for tested samples in the top 10 countries visited by Malaysians in 2023.
On the current initiative by Malaysia to vaccinate senior citizens, Dr Jasmine said it should be expanded to other age groups.
“This is especially for those with underlying health conditions like chronic respiratory issues.
“A broader vaccination strategy can help reduce overall influenza transmission and protect vulnerable populations,” she said.
Aside from senior citizens, Dr Awang Bulgiba said young children were also vulnerable to influenza as they might not have been exposed to the virus.
“As such, their immune system might not be primed for the influenza virus.
“Eventually, when financial conditions allow, I believe that free flu jabs could be extended to young children,” he said.
Dr Jasmine hoped that the government would improve community surveillance to track influenza activity and identify circulating strains, including conduct more accessible testing and reporting.
“Equally important is to ensure adequate vaccine supply and promote vaccination campaigns.
“This ensures that everyone who needs a flu shot can get one, and that people understand why it's so important,” she said.
Dr Jasmine urged everyone to get an annual flu shot as vaccination, describing it as the people’s most powerful tool for protection.
“It's not just about protecting ourselves. It's about protecting our family, friends and community.
“And finally, don't underestimate the impact of simple hygiene practices – handwashing, covering coughs and sneezes – these actions can significantly limit the spread of the virus,” she said.
As Malaysia takes steps to tackle influenza, here’s a list of the peak positive rates for tested influenza samples in other countries around the world.
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