Oral Cavity Identified as Long Term COVID-19 Reservoir That Increases Risk of Oral Health Issues
Nikhil Prasad Fact checked by:Thailand Medical News Team Feb 21, 2025 20 hours, 10 minutes ago
Medical News: Recent scientific findings have revealed that the oral cavity serves as a long-term reservoir for the SARS-CoV-2 virus, potentially contributing to prolonged health complications, including increased susceptibility to periodontal diseases and other viral infections. A comprehensive study conducted by researchers from the University of Illinois Chicago has provided valuable insights into the relationship between COVID-19, long COVID, and oral health deterioration.
Oral Cavity Identified as Long Term COVID-19 Reservoir That Increases Risk of Oral Health Issues
This
Medical News report highlights the key findings from this study, which monitored COVID-19 patients over a four-year period (2020–2024), analyzing the effects of SARS-CoV-2 infection on oral health in diverse populations. The research underscores the critical importance of oral hygiene and regular dental care, particularly for individuals who have experienced COVID-19 infection.
COVID-19 as a Persistent Oral Reservoir
One of the most significant discoveries of the study is that SARS-CoV-2 can persist in the oral cavity long after the initial infection. Although viral RNA may not be detectable in saliva in all cases, the study found that SARS-CoV-2 spike protein was still present in 70% of COVID-positive individuals months after their initial infection. This suggests incomplete viral clearance, raising concerns about prolonged inflammatory responses and increased vulnerability to oral diseases.
The study also identified that individuals with a history of COVID-19 exhibited significantly higher levels of ACE2 and TMPRSS2 receptors in their oral tissues. These receptors facilitate viral entry, potentially allowing SARS-CoV-2 to remain in the body for extended periods, particularly in gum tissues and salivary glands.
Increased Risk of Periodontal Disease in COVID-19 Patients
The research findings demonstrate a strong correlation between previous COVID-19 infection and deteriorating oral health. COVID-positive individuals were found to have a 73.1% increased risk of developing periodontal disease compared to COVID-negative counterparts. Clinical indicators such as gum inflammation, increased plaque buildup, deeper periodontal pockets, and a higher prevalence of tooth loss were significantly more common in individuals with prior SARS-CoV-2 infection.
Moreover, these findings persisted even among vaccinated individuals, indicating that vaccination does not completely eliminate the risks associated with oral health deterioration due to the virus.
Racial Disparities and Oral Health Complications
The study further examined the impact of COVID-19 on different racial and ethnic groups. Black and Hispanic individuals exhibited the highest prevalence of severe periodontal disease and oral complications following COVID-19 infection. The data suggested that systemic health disparities, combined with the effects of prolonged viral persistence, contribute to these increased risks.
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Among Black COVID-19-positive participants, the odds of developing severe gum disease were significantly higher, with an observed bleeding index of 19.6, missing teeth index of 8.3, and increased periodontal pocket depths compared to other racial groups. These findings suggest an urgent need for targeted dental health interventions in underserved communities.
Co-Infections and the Presence of Other Viruses
Another alarming discovery from the study was the increased prevalence of co-infections in long COVID patients. Researchers found that individuals with a history of COVID-19 had significantly higher rates of other oral viruses, including Epstein-Barr virus (EBV) (70.5%), herpes simplex virus (HSV) (8.1%), and human papillomavirus (HPV) (17.5%).
The presence of these viruses, particularly HPV, raises concerns about potential long-term consequences, including an increased risk of oral cancers. The study suggests that SARS-CoV-2 may create a favorable environment for viral persistence and reactivation, contributing to chronic inflammation and potentially exacerbating long COVID symptoms.
The Role of Vaccination in Mitigating Oral Health Risks
Although vaccination has been shown to reduce the severity of acute COVID-19 symptoms, the study found that it does not fully protect against the long-term oral health consequences associated with the virus. Vaccinated COVID-19-positive individuals still exhibited significant oral health deterioration, though to a lesser extent than unvaccinated individuals.
For example, the study observed a decrease in periodontal pocket depth from an average of 5.4 mm in unvaccinated COVID-19-positive patients to 3.3 mm in vaccinated individuals. Similarly, the bleeding index improved slightly in vaccinated individuals but remained significantly elevated compared to those who had never contracted COVID-19.
Mechanisms Behind Oral Health Decline in Long COVID Patients
To further investigate the underlying causes of oral health decline in long COVID patients, the study examined molecular markers associated with inflammation and viral persistence. Researchers found significantly higher levels of inflammatory cytokines, such as IL-6 and TNF-α, in saliva samples from COVID-19-positive individuals. These markers are known to contribute to chronic inflammation and tissue damage, which may explain the persistent oral health complications observed in long COVID patients.
Additionally, researchers identified an increased expression of SARS-CoV-2 entry receptors (ACE2 and TMPRSS2) in the gum tissues of long COVID patients. This suggests that the virus may continue to interact with oral tissues, leading to prolonged immune activation and increased susceptibility to secondary infections.
Long-Term Implications and Need for Preventive Dental Care
The findings from this study highlight the need for enhanced dental monitoring and preventive care for individuals who have experienced COVID-19. Given the persistent presence of SARS-CoV-2 in oral tissues and the increased risk of periodontal disease, regular dental check-ups, improved oral hygiene practices, and access to specialized periodontal care may be crucial in mitigating the long-term effects of COVID-19 on oral health.
Healthcare professionals and policymakers are urged to consider the inclusion of oral health assessments in long COVID management strategies, particularly for individuals from high-risk populations. Increased public awareness about the connection between COVID-19 and oral health is also essential to encourage early intervention and preventive measures.
Conclusion
The study provides compelling evidence that the oral cavity serves as a long-term reservoir for SARS-CoV-2, contributing to prolonged health complications such as periodontal disease and increased susceptibility to other viral infections. The persistent presence of viral proteins, elevated inflammatory markers, and an increased risk of co-infections highlight the need for targeted oral health interventions.
Moreover, the findings emphasize the racial disparities in oral health outcomes following COVID-19 infection, underscoring the importance of equitable healthcare access. While vaccination offers some protection against severe disease, it does not entirely eliminate the risks associated with long COVID oral manifestations.
In light of these findings, individuals who have had COVID-19 should prioritize their oral health by seeking regular dental care and practicing good hygiene. Further research is needed to explore potential treatment strategies that can help mitigate the long-term effects of COVID-19 on oral health.
The study findings were published on a preprint server and are currently being peer reviewed.
https://www.biorxiv.org/content/10.1101/2025.02.17.638734v1
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