Nikhil Prasad Fact checked by:Thailand Medical News Team Nov 24, 2025 31 minutes ago
Medical News: A New Look at How COVID-19 Affects the Mouth
A new study has revealed that the SARS-CoV-2 spike protein alone can severely disrupt the salivary glands, causing inflammation and autoimmune-like reactions even without the full virus being present. Researchers from The ADA Forsyth Institute in the United States, the Universidade Federal de Minas Gerais in Brazil, the ADA Science and Research Institute in Maryland, and Virginia Commonwealth University carried out this investigation using healthy laboratory mice. Their findings help explain why many COVID-19 and Long COVID patients continue to experience dry mouth, oral discomfort, and immune problems long after the initial infection. This
Medical News report highlights key findings from the study.
Study finds the SARS-CoV-2 spike protein alone can damage salivary glands and trigger autoimmune-like reactions
Spike Protein Alone Reduces Saliva Production
The researchers directly injected small amounts of the SARS-CoV-2 spike protein into the salivary glands of mice to mimic how the protein may linger in human tissues. They compared these animals to mice receiving either a harmless solution or another viral protein called the envelope protein. Only the spike protein caused a sharp drop in saliva flow. This means the spike protein, by itself, is capable of weakening the glands responsible for producing saliva.
Inflammation and Immune Cell Invasion
Tissue samples from the affected glands revealed clear clusters of white blood cells, similar to what doctors see in autoimmune conditions like Sjögren’s disease. Two-thirds of the spike-treated mice showed these immune clusters, while the other mice showed none. Detailed immune analyses showed increases in activated B cells and T cells inside the glands and signs that the immune system had shifted into a more aggressive, inflammatory state.
Remarkably, one-third of the mice also developed antinuclear antibodies—markers commonly seen in autoimmune diseases. This mirrors real-world findings where many COVID-19 patients test positive for such antibodies during and after infection.
Deep Molecular Damage Inside the Glands
RNA sequencing revealed that key genes needed for healthy saliva production were significantly reduced. At the same time, genes linked to inflammation, tissue stress, fibrosis, and abnormal immune signaling were switched on. The scientists also discovered a strong rise in phosphorylated STAT3, a protein known to drive inflammation and tissue injury, especially during severe COVID-19.
Conclusions
These findings show that the SARS-CoV-2 spike protein alone can damage the salivary glands, reduce their ability to produce saliva, trigger powerful immune infiltration, distort normal cell function, and even spark autoimmune-like reactions. The results suggest that persistent spike protein in tissues may contribute to chronic oral and glandular symptoms seen in many Long
COVID patients. Understanding these mechanisms may lead to better treatments for lingering post-COVID complications affecting the mouth and salivary system.
The study findings were published in the peer reviewed journal: Frontiers in Immunology.
https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2025.1667597/full
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Medical News.
Read Also:
https://www.thailandmedical.news/articles/coronavirus
https://www.thailandmedical.news/articles/long-covid
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