At-home taste test can predict COVID-19 duration and severity

A JAMA Network Open research paper published by Doctorpedia contributor Henry P. Barham, M.D correlating an association between the bitter taste receptor phenotype and clinical outcomes among patients with COVID-19 has confirmed that an at-home taste test could be a gamechanger in predicting duration and symptom severity of the virus. 

Speaking to Doctorpedia, Dr. Henry P. Barham explains that the study suggests that T2R38 receptor allelic variants were associated with participants’ innate immune response toward SARS-CoV-2. The T2R phenotype was associated with patients’ clinical course after SARS-CoV-2 infection. Non-tasters were more likely to be hospitalised and experience more severe and long-lasting symptoms with SARS- CoV-2 than the other two groups, suggesting enhanced innate immune protection against SARS-CoV-2.

Doctorpedia founding medical partner Dr. Sanjay Juneja, who conducted the interview with Dr. Barham to learn more about the implications that these scientific findings will have for COVID-19 diagnosis, said: “The taste receptors in your mouth - especially to bitterness - if you're what we call a supertaster, [...] it can actually affect how well you clear viruses so much so that people that are able to taste bitterness really have a much higher clearance rate to prevent that virus from going into your body.

Dr. Henry Barham added: “The data has shown in this study that this test can help predict duration and severity of symptoms. Meaning: yes, if you have a new strain of this Coronavirus or it mutates, or you have some other new novel virus - this should stay true because it's part of your innate immunity and we've actually now studied it to other viruses, not just COVID […] And so I would argue it actually is a good way to help stratify the order in which people could receive vaccination, especially in countries where resources are limited.”

The study suggests that bitter taste receptors appear to play a crucial role in the innate immunity against upper respiratory tract pathogens, and the allelic variants of these receptors define the magnitude of such innate immunity. These results could explain why some seemingly healthy young people experience worse symptoms than others and why treatments including hydroxychloroquine showed promise, because it activated the Tas2R receptor.

With this simple taste test, Dr Barham and his team were able to separate the study participants into three groups: super-tasters, tasters, and non-tasters. Dr. Barham shared the results in this exclusive interview with Doctorpedia: “Of those requiring hospitalisation, 85% were non tasters, 0% were super-tasters, 15% were in the middle group [tasters.] Now the interesting point there is that of those 15% requiring hospitalisation (that were in the middle group), the youngest one was 69. And the average age is 74. That's a wear off of the receptors, meaning they are in the middle group, but as you get older, they wear down and you start to trend towards the non-taster group.”

In the cohort study of 1935 adults, 266 tested positive for SARS-CoV-2 and those who experienced the low intensity of bitter tastes or no bitter tastes (non-tasters) were significantly more likely to test positive for SARS- CoV-2, to be hospitalised, and to be symptomatic for a longer duration. Conversely, those who experienced the greater intensity of bitter tastes (supertasters) represented 5.6% of patients infected with SARS-CoV-2, suggesting enhanced innate immune protection. 

The study also found that the taste expression was strongly connected to the duration of symptoms. On average, super-tasters experienced five days of symptoms, Tasters experienced 13.5 days of symptoms, and non-tasters experienced 23.7 days of symptoms. The P-value is the chance that the results happened by coincidence, with anything less than 0.05 being statistically significant. The P-value with this study was as low as it can be: 0.001 (listed as 0.01).

According to Dr Barham, this taste test that is affordable, scalable, and accurate could help people gain a better understanding of their potential complication risk from COVID-19 and other diseases and variants.

He said: “We've actually refined a test that is incredibly accurate, to the point of around 94.2% accuracy in predicting genotype.”