Just when you thought you’re well stocked with antigen rapid test or ART kits, you spot a new hybrid on the pharmacy shelves – three-in-one ART kits that not only test for COVID-19, but also influenza A and B.
Now, why would you need to know whether your sniffles are caused by influenza A or B? Wouldn’t taking an MC, popping a paracetamol and sleeping the flu off usually take care of things? We find out why it is important to make the distinction between influenza A and B – and why you may find more such three-in-one ART kits in the stores.
There are actually not just two but four influenza viruses in total – A, B, C and D – and they’re the causes behind their respective influenza types. However, less focus is placed on influenza C and D. That’s because influenza C infections “generally cause mild illness”, while the D type primarily affects cattle, according to the US Centers For Disease Control And Prevention.
“Influenza A and B viruses are more concerning,” said Professor Paul Tambyah, a professor of medicine and the deputy chair of the Infectious Diseases Translational Research Programme at National University of Singapore’s Yong Loo Lin School of Medicine.
Of the two, “influenza A tends to be a bit more serious than influenza B”, said Prof Tambyah. Although influenza B tends to cause more muscle aches, influenza A can lead to higher risks of developing pneumonia, he said. Influenza A is also responsible for flu outbreaks and pandemics.
(Photo: iStock/Pornpak Khunatorn)
"Although influenza A tends to be more commonly found here, both viruses circulate quite widely," said Prof Tambyah, citing the latest report by the Ministry Of Health. "It shows that influenza A accounted for 78 per cent of the influenza cases detected in July with influenza B accounting for 12 per cent." However, this breakdown varies from month to month.
As for the annual flu season that you often hear about, it is different in Singapore and other tropical countries, said Associate Professor Barnaby Young, a senior consultant at the National Centre for Infectious Diseases. While temperate regions have a distinct flu season usually in winter, “it is much more complex and varies from year to year” in Singapore.
“Typically, we experience two peaks a year – one from about December to March, and another from May to August,” said Assoc Prof Young. But beyond those two periods, influenza viruses also circulate and cause year-round infections, he said.
Differentiating between influenza and COVID-19 can mean prescribing the right antiviral medication, said Assoc Prof Young. Oseltamivir is used for both influenza A and B, while Paxlovid is for COVID-19. “These can help speed recovery and reduce the risk of developing a severe illness,” he said, useful when you have very young ones or elderly folks at home.
But if that’s the case, why didn’t your family doctor perform an in-clinic test on you back before self-test kits were available? Even now, you’re often sent home with an MC and some medicine. No swabbing, nothing taken.
(Photo: iStock/Memorystockphoto)
For most treatments, said Assoc Prof Young, medications such as paracetamol, antihistamines and cough medicine may be sufficient to treat the symptoms, and “there is no need to know exactly what virus is causing the infection”.
Other reasons are the cost of the in-clinic test kits and the time involved in testing. “Testing for different viruses requires sending off a swab to a lab, with the results only coming back one to two days later. And this lab test may be expensive,” said Assoc Prof Young.
And that’s where these three-in-one self-test kits can come in handy, said Prof Tambyah. “Both influenza and COVID-19 are more serious than common colds, so for the patient, it is good to know which virus they are infected with.”
They are also useful when you have elderly relatives at home. “You might need to be a bit more alert with influenza A than influenza B," he said. It is also more crucial to differentiate for “patients who would not ordinarily be isolated or hospitalised”, and potentially spread a highly contagious virus.
The hybrid kits contain three different antigens that react to influenza A and B antibodies as well as SARS-CoV-2 antibodies in your nasal sample. If positive, a line would appear next to the relevant viral infection in the cartridge’s window, much like how the usual ART kits for COVID-19 work.
(Photo: iStock/wichayada suwanachun)
“However, they are less sensitive, so while a positive result gives us confidence that a particular virus is causing the infection, a negative result needs to be interpreted more carefully,” said Assoc Prof Young. This is because a negative test result does not mean you don't have an infection; there are many other viruses and bacteria that can cause respiratory symptoms that are not covered by these three-in-one kits, he said.
“Even with a negative result, it is important to take protective measures such as avoiding crowded areas, wearing a mask if you have to go out, and taking time off work,” advised Assoc Prof Young.
There are several brands available in the pharmacies and online – as well as a kit that is being developed locally by Singapore-based company Cellbae. Funded by the Integrated Innovations In Infectious Diseases or I3D grant awarded by the National Medical Research Council, the prototype is currently being tested on students from the National University Health System with flu-like illnesses. No commercial release date has been provided yet.
With some options to choose from, how do you decide? “As long as the kit has been approved by the local health authorities, it would have met the necessary standards for quality and accuracy,” said Assoc Prof Young.
“Some kits are easier to use than others, and some may even test for additional viruses such as respiratory syncytial virus – a four-in-one test,” he said. “But otherwise, the general public can opt for the cheapest option
Continue reading...
Now, why would you need to know whether your sniffles are caused by influenza A or B? Wouldn’t taking an MC, popping a paracetamol and sleeping the flu off usually take care of things? We find out why it is important to make the distinction between influenza A and B – and why you may find more such three-in-one ART kits in the stores.
WHAT’S THE DIFFERENCE BETWEEN INFLUENZA A AND B?
There are actually not just two but four influenza viruses in total – A, B, C and D – and they’re the causes behind their respective influenza types. However, less focus is placed on influenza C and D. That’s because influenza C infections “generally cause mild illness”, while the D type primarily affects cattle, according to the US Centers For Disease Control And Prevention.
“Influenza A and B viruses are more concerning,” said Professor Paul Tambyah, a professor of medicine and the deputy chair of the Infectious Diseases Translational Research Programme at National University of Singapore’s Yong Loo Lin School of Medicine.
Of the two, “influenza A tends to be a bit more serious than influenza B”, said Prof Tambyah. Although influenza B tends to cause more muscle aches, influenza A can lead to higher risks of developing pneumonia, he said. Influenza A is also responsible for flu outbreaks and pandemics.
(Photo: iStock/Pornpak Khunatorn)
WHICH INFLUENZA TYPE DO WE COMMONLY HAVE IN SINGAPORE?
"Although influenza A tends to be more commonly found here, both viruses circulate quite widely," said Prof Tambyah, citing the latest report by the Ministry Of Health. "It shows that influenza A accounted for 78 per cent of the influenza cases detected in July with influenza B accounting for 12 per cent." However, this breakdown varies from month to month.
As for the annual flu season that you often hear about, it is different in Singapore and other tropical countries, said Associate Professor Barnaby Young, a senior consultant at the National Centre for Infectious Diseases. While temperate regions have a distinct flu season usually in winter, “it is much more complex and varies from year to year” in Singapore.
“Typically, we experience two peaks a year – one from about December to March, and another from May to August,” said Assoc Prof Young. But beyond those two periods, influenza viruses also circulate and cause year-round infections, he said.
WHY DO YOU NEED TO TELL THE DIFFERENCE BETWEEN INFLUENZA A AND B, AND COVID-19?
Differentiating between influenza and COVID-19 can mean prescribing the right antiviral medication, said Assoc Prof Young. Oseltamivir is used for both influenza A and B, while Paxlovid is for COVID-19. “These can help speed recovery and reduce the risk of developing a severe illness,” he said, useful when you have very young ones or elderly folks at home.
But if that’s the case, why didn’t your family doctor perform an in-clinic test on you back before self-test kits were available? Even now, you’re often sent home with an MC and some medicine. No swabbing, nothing taken.
(Photo: iStock/Memorystockphoto)
For most treatments, said Assoc Prof Young, medications such as paracetamol, antihistamines and cough medicine may be sufficient to treat the symptoms, and “there is no need to know exactly what virus is causing the infection”.
Other reasons are the cost of the in-clinic test kits and the time involved in testing. “Testing for different viruses requires sending off a swab to a lab, with the results only coming back one to two days later. And this lab test may be expensive,” said Assoc Prof Young.
And that’s where these three-in-one self-test kits can come in handy, said Prof Tambyah. “Both influenza and COVID-19 are more serious than common colds, so for the patient, it is good to know which virus they are infected with.”
They are also useful when you have elderly relatives at home. “You might need to be a bit more alert with influenza A than influenza B," he said. It is also more crucial to differentiate for “patients who would not ordinarily be isolated or hospitalised”, and potentially spread a highly contagious virus.
HOW DO THESE THREE-IN-ONE TEST KITS WORK? HOW DO YOU CHOOSE?
The hybrid kits contain three different antigens that react to influenza A and B antibodies as well as SARS-CoV-2 antibodies in your nasal sample. If positive, a line would appear next to the relevant viral infection in the cartridge’s window, much like how the usual ART kits for COVID-19 work.
(Photo: iStock/wichayada suwanachun)
“However, they are less sensitive, so while a positive result gives us confidence that a particular virus is causing the infection, a negative result needs to be interpreted more carefully,” said Assoc Prof Young. This is because a negative test result does not mean you don't have an infection; there are many other viruses and bacteria that can cause respiratory symptoms that are not covered by these three-in-one kits, he said.
“Even with a negative result, it is important to take protective measures such as avoiding crowded areas, wearing a mask if you have to go out, and taking time off work,” advised Assoc Prof Young.
There are several brands available in the pharmacies and online – as well as a kit that is being developed locally by Singapore-based company Cellbae. Funded by the Integrated Innovations In Infectious Diseases or I3D grant awarded by the National Medical Research Council, the prototype is currently being tested on students from the National University Health System with flu-like illnesses. No commercial release date has been provided yet.
With some options to choose from, how do you decide? “As long as the kit has been approved by the local health authorities, it would have met the necessary standards for quality and accuracy,” said Assoc Prof Young.
“Some kits are easier to use than others, and some may even test for additional viruses such as respiratory syncytial virus – a four-in-one test,” he said. “But otherwise, the general public can opt for the cheapest option
Continue reading...