Taste dysfunction in long COVID, 2026, Morad et al.

[Chandelier]

Taste dysfunction in long COVID

Spoiler: Authors

Morad, Hanna; Vanhala, Tytti; Kisiel, Marta A; Andreason, Agnes; Li, Mei; Andersson, Göran; Laurell, Göran; Finger, Thomas E; Hellekant, Göran

Abstract​

Persistent taste dysfunction is frequently reported in individuals with post-acute sequelae of infection by SARS-CoV-2 (long COVID).
The mechanisms and pathological correlates underlying this taste dysfunction are unknown.
This study investigates the underlying pathology in 28 non-hospitalized subjects diagnosed with COVID-19 who experienced taste disturbances more than 12 mo after testing positive for SARS-CoV-2.

To objectively establish the nature of the taste deficit, we used the WETT taste test, which quantifies the subject's ability to taste each of the 5 taste qualities: sweet, umami, bitter, sour, and salty.
We then biopsied 5 to 8 fungiform taste papillae (FP) in 20 of the 28 subjects.
The FPs were analyzed histologically for overall taste bud (TB) structure and innervation and by quantitative PCR (qPCR) for mRNA expression of markers for different taste receptor cells.
Although all subjects had reported taste dysfunction, only 3 showed overall taste scores below the 10th percentile for a normal population adjusted for age and sex.
However, 11 of the 28 subjects exhibited total loss of one or more taste qualities.
Loss of PLCβ2-dependent taste qualities (sweet, umami, and bitter) was significantly more common and was correlated with reduced expression of PLCβ2 and Tas1R3 mRNAs.
Histological analysis revealed generally preserved TB structure and innervation but with occasional disorganized TBs and abnormal, isolated PLCβ2-positive cells in the epithelium.

Our findings suggest long-term taste dysfunction after COVID-19 occurs rarely—more frequently involving PLCβ2-dependent taste qualities—but is not due to wholesale disruption of the taste periphery.


Web | DOI | PDF | Chemical Senses

 

[Dolphin]

https://www.eurekalert.org/news-releases/1118387

News Release 2-Mar-2026

Study identifies molecular cause of taste loss after COVID​

Research links persistent loss of sweet, bitter and umami taste to reduced levels of key taste-cell protein

Peer-Reviewed Publication
University of Colorado Anschutz


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AURORA, Colo. (Jan. 29, 2026) – Scientists have identified molecular and structural changes in taste buds that may explain why a small subset of people experience long-term taste loss after COVID-19 infection.

The study, published last month in Chemical Senses, provides the first direct evidence linking patients’ reported taste changes to measurable biological abnormalities inside taste cells.

What causes long-term taste loss after COVID-19?

Researchers from the University of Colorado Anschutz and two Swedish universities studied 28 non-hospitalized patients who reported persistent taste disturbances more than one year after contracting COVID-19.

Key findings:

• 8 of 28 patients showed clearly abnormal taste test scores
• 11 patients reported specific loss of sweet, bitter and umami taste
• Salty and sour taste were largely preserved

To understand why, researchers performed biopsies on taste buds from 20 participants.

Molecular defect identified in taste receptor cells

The team, organized by Göran Hellekant, PhD, of the University of Wisconsin and the Swedish University Of Agricultural Sciences, discovered reduced levels of messenger RNA (mRNA) responsible for producing a protein called PLCβ2 — a critical signal amplifier in receptor cells that detect sweet, bitter and umami tastes.

“PLCβ2 acts like a molecular amplifier inside taste cells,” said Thomas Finger, PhD, professor of cell and developmental biology at the University of Colorado Anschutz and corresponding author of the study. “It strengthens the signal before it’s transmitted to the brain. When levels are reduced, the taste signal weakens.”

Importantly, taste cells that detect salty and sour flavors do not rely on this protein, which may explain why those tastes are less affected.

Structural changes also observed

In addition to molecular abnormalities, some patients showed altered taste bud organization under microscopic examination.

“Some subjects had normal-looking taste buds, while others showed structural disorganization,” Finger said. “This suggests that both molecular and architectural changes may contribute to persistent taste dysfunction.”

Why does taste loss persist?

Taste bud cells are normally replaced every two to four weeks. But the researchers found evidence that cellular signaling disruptions may persist far longer in certain individuals.

While most COVID-19 patients recover their sense of taste within weeks or months, this study provides quantitative biological evidence explaining why recovery may be prolonged in a small group.

“Our findings offer measurable evidence of long-term taste disruption in some post-COVID patients long after the virus has been cleared,” the authors write.

Further research is needed to determine whether the molecular dysfunction can fully reverse and whether targeted therapies might restore normal taste signaling.

About the University of Colorado Anschutz


The University of Colorado Anschutz is a world-class academic medical campus leading transformative advances in science, medicine, education and patient care. The campus includes the University of Colorado’s health professional schools, more than 60 centers and institutes, and two nationally ranked independent hospitals - UCHealth University of Colorado Hospital and Children's Hospital Colorado - which see nearly three million adult and pediatric patient visits each year. Innovative, interconnected and highly collaborative, CU Anschutz delivers life-changing treatments, exceptional patient care and top-tier professional training. The campus conducts world-renowned research supported by $890 million in funding, including $762 million in sponsored awards and $128 million in philanthropic gifts for research.

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Journal​

Chemical Senses

Method of Research​

Experimental study

Subject of Research​

People

Article Title​

Taste dysfunction in long COVID

Article Publication Date​

29-Jan-2026