Influenza causes an estimated 500,000 deaths each year and tests that detect the virus are key to treating, and preventing the spread of, influenza. Towards this end, scientists from University of Würzburg are now working on a test that allows people all over the world to taste their flu infection (think: chewing gum, lollipops, lozenges). The rationale is that a taste-based test is less expensive to produce, faster, and more accessible around the world.
What types of flu tests already exist?
These scientists were interested in creating a new flu test because the current diagnostic tests, such as PCR-based tests, are slow and expensive. While PCR-based tests are highly accurate, many parts of the world cannot access these tests and when patients get them, they can wait up to 24 hours or more for a test result. Other tests, such as antigen tests are faster (~15 minutes) but have lower accuracy than PCR-based tests.
Because influenza can be infectious as early as 1-2 days before symptoms appear, the researchers wanted to build a test that could be widely used during the early phase of infection. This could help identify infections before they have had a chance to spread widely to prevent outbreaks. However such a task requires screening tools to be cost-effective and widely accessible. Current tests don’t make sense logistically for this purpose.
How does the taste-based flu test work?
To create this test, the researchers honed in on a step of the viral replication process. To replicate, the virus uses an enzyme called neuraminidase to release newly produced viruses from sialic acids on the host cell’s surface.
Neuraminidase activity peaks early in the course of infection making this enzyme a good choice to target for the sensor.
The researchers co-opted this process to develop their sensor by creating a similar bond between a sialic acid and a molecule called thymol. Thymol is a molecule in the herb thyme, responsible for the taste we’re familiar with. In the presence of the flu virus, its neuraminidase enzyme will separate the sugar from thymol, resulting in a taste. Without flu, thymol stays attached to the sugar, with no taste.
Early studies, promising results
The researchers are early on their path to deploying their sensor in the real world. Their current studies are proof-of-priciple showing that the sensor is specific to viral neuraminidase and not bacterial neuraminidase, meaning that any bacteria in the mouth won’t interfere with the results. When they tested their sensor on the saliva from flu patients, they found that the thymol molecules were released within 30 minutes. In the future, the scientists of the study hope that they can shorten the detection time. Soon, the scientists plan to test their sensor on actual humans with the ultimate goal of confirming taste in people with presymptomatic and postsymptomatic influenza.
When put to use, the researchers envision using these types of tests initially for widespread screening (ex: in settings where transmission likely occurs) then followed by the more accurate (slower and more expensive) tests for confirmation.
Further reading:
A Viral Neuraminidase-Specific Sensor for Taste-Based Detection of Influenza. ACS Central Science. 2025.
Flu Test. Cleveland Clinic. Last reviewed 2025.
When should I get my flu shot? Here’s what science says. The Microbial Menagerie. Last updated 2025.
Featured image source: NIH
