Translate this page into:
Xerostomia after COVID-19 recovery: A preliminary investigation
For correspondence: Dr Deepika Bablani Popli, Department of Oral Pathology and Microbiology, Faculty of Dentistry, Jamia Millia Islamia, New Delhi 110 025, India e-mail: deepikabablani@gmail.com; dpopli@jmi.ac.in
-
Received: ,
Accepted: ,
How to cite this article: Shakeel A, Sircar K, Bablani Popli D. Xerostomia after COVID-19 recovery: A preliminary investigation. Indian J Med Res. 2026;163:122-5. DOI: 10.25259/IJMR_1570_2025.
Abstract
Background and objectives
Xerostomia, or dry mouth, was frequently reported during COVID-19 infection, but its persistence after recovery remains underexplored. This study aimed to assess the prevalence and duration of xerostomia following recovery from COVID-19 infection.
Methods
This observational study included 50 participants who had recovered from COVID-19. They were surveyed using a xerostomia assessment questionnaire and underwent the modified Schirmer test (MST) to measure their salivary flow rate.
Results
Overall, n=31(62%) of participants reported one or more xerostomia-related symptoms after recovery. “Feeling of dry mouth” (n=22, 44%) was the most common, followed by nocturnal water intake (n=18, 36%), difficulty swallowing dry food (n=7, 14%), and reliance on liquids during swallowing (n=6, 12%). Hyposalivation (MST <15 mm at 3 min) was observed in 10% (n=5) of participants, all of whom were infected during the second wave (Delta variant). A significant association was noted between self-reported dry mouth and MST findings (P=0.029). Symptoms persisted up to 15 months post-recovery.
Interpretation and conclusions
Xerostomia may persist after COVID-19 recovery, with potential implications for oral health. Early recognition and management are warranted.
Keywords
COVID-19
Long COVID
Post-COVID conditions
Xerostomia
COVID-19 impacted over 779 million individuals worldwide, including 45 million in India.1 Even after recovery, many patients continue to experience lingering symptoms, a condition known as post-acute sequelae of SARS-CoV-2 infection (PASC), or long COVID. This syndrome is characterised by persistent, relapsing, or new symptoms such as fatigue, brain fog, dizziness, gastrointestinal issues, and changes in sensory functions like smell and taste. Among these, oral symptoms, particularly dry mouth (xerostomia), have been frequently reported.2
Xerostomia, defined as a subjective sensation of oral dryness, often results from reduced salivary flow and can lead to significant oral health problems, including an increased risk of dental caries, periodontitis, and oral infections such as candidiasis.3 Xerostomia has been reported as an early symptom of COVID-19.4,5 Follow up studies have reported persistence of xerostomia after recovery; however, there is a lack of research evaluating this symptom in post-COVID-19 patients over longer durations.2,6,7 This study aimed to determine the prevalence of xerostomia and assess its persistence in individuals who had recovered from COVID-19.
Methods
This observational study was conducted over two months (June 16, 2022 to July 31, 2022) at the department of Oral Pathology & Microbiology, Faculty of Dentistry, Jamia Millia Islamia, New Delhi, India. Ethical clearance was granted by the Institutional Ethical Committee, and written informed consent was obtained from all the participants.
Participants
Fifty adults (25 males, 25 females; 18–65 yr) who had recovered from COVID-19 and attended the dental outpatient were recruited. The sample size was limited by single-center design and pandemic-related constraints. Participants represented different COVID-19 waves, forming distinct groups for comparison.
This study included recovered COVID-19 patient with confirmed positive report. Recovery as per clinical guidance: ≥7 days post-positive with 3 afebrile days (homecare) or physician-certified discharge (hospitalised cases). The age group was 18–65 year (age>65) excluded due to naturally higher xerostomia prevalence).8 Participants with history of xerostomia before COVID-19/salivary gland disease/surgery/or head/neck radiation prior to infection were also excluded.
Study design
This study was planned to analyse xerostomia both subjectively using a standard questionnaire as well as objectively by measurement of unstimulated salivary flow. A standardised questionnaire was used to gather demographic information and assess xerostomia symptoms through interviews.9
Following the administration of the questionnaire, the unstimulated salivary flow was recorded for all participants using commercially available Schirmer strips (Unitech Vision, India). These strips were What-man filter paper no 41 strips with graduated scale (0-35 mm) markings placed in the floor of the mouth beside the lingual frenum. Measurements were taken at 1, 2, and 3 min, during morning hours (9:00 am–12:00 PM) to control for diurnal variations. Participants were instructed to refrain from eating or drinking two hours before the test. A reading of <15 mm after 3 min indicated hyposalivation.10,11 Modified Schirmer test (MST) readings were categorised into <15 mm, 15–25 mm, and >25 mm at 3 min, and results are presented as frequencies and percentages, as the test provides ordinal diagnostic cut-offs rather than continuous scale values for analysis.
Data were recorded in Excel and analysed using descriptive statistics, including mean, standard deviation, frequencies, and percentages. The association between xerostomia questionnaire responses and MST scores was evaluated using the Chi-square test (P<0.05 significant).
Results
The study comprised 50 participants (25 males, 25 females; age 18–60 yr) with confirmed COVID-19 infection between March 2021 and May 2022. Twenty (40%) reported oral symptoms during the acute phase, including dryness (n=8, 16%), altered taste (n=3, 6%), and complete loss of taste (n=15, 30%).
A total of (n=31,62%) participants reported at least one xerostomia-related symptom. The most frequent complaint was persistent dry mouth (n= 22, 44%), followed by waking at night to drink water (n= 18, 36%), difficulty swallowing dry food (n= 7, 14%), and reliance on liquids while swallowing (n= 6, 12%). Details of symptom distribution across recovery durations are provided in Table. These findings indicate that xerostomia persists long after clinical recovery.
| Duration (total number of study participants) | Does your mouth feel dry? | Do you have difficulty swallowing dry food? | Do you sip liquid to aid in swallowing? | Do you wake up at night to drink water? | Did you experience loss of taste or burning mouth when you were suffering from COVID-19? | If yes, do you still experience loss of taste/alteration of taste/burning sensation? | Modified Schirmer test < 15 mm |
|---|---|---|---|---|---|---|---|
| <5 months (19) | 5 (26.3%) | 4 (21.1%) | 2 (10.5%) | 6 (31.6%) | 8 (42.1%) | 1 (5.3%) | 0 (0%) |
| 5-10 months (4) | 1 (25%) | 1 (25%) | 1 (25%) | 1 (25%) | 1 (25%) | 0 (0%) | 1 (25%) |
| 11-15 months (27) | 16 (59.3%) | 2 (7.4%) | 3 (11.1%) | 11 (40.7%) | 11 (40.7%) | 1 (3.7%) | 4 (14.8%) |
Objective evaluation with the Modified Schirmer Test (MST) revealed <15 mm wettability at 3 min in 10% of participants, 15–25 mm in 26%, and >25 mm in 64% (Figure). Hyposalivation was observed in 10% (n=5; 3F, 2M) and was significantly associated with self-reported xerostomia (P=0.029).
-
Assessment of xerostomia. (A) Subjective symptoms of Xerostomia after recovery from COVID-19; (B) Modified Schirmer test after 3 min.
Sex-specific analysis revealed a significant difference at 2 min (P=0.018), with females more likely to record higher MST values (>25 mm). However, the difference was not maintained at 3 min, suggesting no sustained sex-based disparity.
Discussion
In summary, Xerostomia was reported in 62% of recovered COVID-19 patients and objectively confirmed in 10%. Symptoms persisted beyond one year, particularly among those infected during the Delta wave. Previous studies have documented persistence in 40.1% of patients at 2–4 wk, 11% at 3 months, and 14.4% at 8 months,6,12,13 but data beyond this period are scarce. In the present study, symptoms were still evident up to 15 months post-infection, supporting reports of prolonged salivary dysfunction.2,13,14
The association of hyposalivation with self-reported xerostomia, is in alignment with earlier studies showing parallel subjective and objective salivary changes after COVID-19, where 46.7% reported xerostomia and 18% had reduced salivary flow at 2–4 wk.6
The persistence of xerostomia may be linked to viral affinity for ACE2 and TMPRSS2, highly expressed in salivary gland epithelial cells.15,16 SARS-CoV-2 has been detected in saliva both early and late in infection.17 Viral tropism may induce direct glandular injury, chronic inflammation, and fibrosis, resulting in long-lasting functional impairment.18,19 This mechanism explains why xerostomia may persist even after resolution of other acute symptoms such as anosmia or dysgeusia.
Hyposalivation was confined to individuals infected during India’s second wave (Delta variant), consistent with reports that long COVID was more common after Delta (10.8%) than Omicron (4.5%).20 The transient differences seen in salivary flow between males and females may reflect variations in salivary kinetics or hormonal influences. Additionally, hormonal fluctuations in perimenopausal women (45–55 yr) are known to affect salivary gland function and may act as a confounding factor influencing xerostomia prevalence in this age group.
The clinical impact of persistent xerostomia extends beyond oral discomfort. It increases risk of dental caries, periodontal disease, mucosal lesions, and candidiasis, and significantly reduces oral health-related quality of life (OHRQoL), contributing to physical and psychological burden.3,21 Given its persistence, dentists and physicians should consider xerostomia a potential marker of post-COVID sequelae and incorporate symptom screening in follow up care.
This study has several limitations. The sample size was modest due to the single-center design and strict recruitment during the pandemic. Disease severity, comorbidities, and medication history—factors influencing xerostomia—were not assessed. A control group was not feasible, as identifying uninfected individuals during widespread community exposure was impractical. The cross-sectional design also precludes causal or temporal inferences. Nevertheless, the findings provide important preliminary evidence from an Indian cohort, extending knowledge on the persistence of xerostomia up to 15 months post-recovery.
These results highlight the need for routine evaluation of xerostomia in post-COVID patients and emphasise the importance of larger, longitudinal studies to clarify its trajectory and management.
Acknowledgment
Prof. Srikant N, Head, Department of Oral Pathology and Microbiology, Manipal College of Dental Sciences, Mangaluru for contributions to the statistical analysis.
Author contributions
AS: Methodology, investigation, data curation, formal analysis, manuscript writing; KS: Conceptualization and supervision, manuscript writing; DBP: Conceptualization and supervision, methodology, investigation, data curation, formal analysis, manuscript writing. All authors have read and approve the final printed version of the manuscript.
Financial support and sponsorship
The study received funding support from Indian Council of Medical Research- Short Term Studentship (2022-03267) awarded to first author (AS) under the guidance of corresponding author (DBP).
Conflicts of Interest
None.
Use of Artificial Intelligence (AI)-Assisted Technology for manuscript preparation
The authors confirm that there was no use of AI-assisted technology for assisting in the writing of the manuscript and no images were manipulated using AI.
References
- World Health Organization. WHO COVID-19 dashboard. Available from: https://covid19.who.int/, accessed on June 5, 2025.
- Post acute sequelae of SARS-CoV-2 infection – reply. JAMA.. 2023;330:1492.
- [CrossRef] [PubMed] [Google Scholar]
- Xerostomia: An update for clinicians. Aust Dent J.. 2010;55:238-44.
- [CrossRef] [PubMed] [Google Scholar]
- Xerostomia and COVID-19: Unleashing pandora’s box. Ear Nose Throat J.. 2021;100:139S.
- [CrossRef] [PubMed] [Google Scholar]
- Oral manifestations of COVID-19 – A literature review. Rev Med Virol.. 2022;32:e2248.
- [CrossRef] [PubMed] [PubMed Central] [Google Scholar]
- Evaluation of xerostomia, taste and smell impairments after COVID-19. Med Oral Patol Oral Cir Bucal.. 2021;26:e568-75.
- [CrossRef] [PubMed] [PubMed Central] [Google Scholar]
- Oral manifestations in mild-to-moderate cases of COVID-19 viral infection in the adult population. Dent Med Probl.. 2021;58:7-15.
- [CrossRef] [PubMed] [Google Scholar]
- Xerostomia: Prevalence, diagnosis, and management. Compend Contin Educ Dent.. 2009;30:326-8.
- [PubMed] [Google Scholar]
- Shortening the xerostomia inventory. Oral Surg Oral Med Oral Pathol Oral Radiol End.. 2011;112:322-7.
- [CrossRef] [Google Scholar]
- Using the modified Schirmer test to measure mouth dryness: A preliminary study. J Am Dent Assoc.. 2005;136:164-70.
- [CrossRef] [PubMed] [Google Scholar]
- Modified Schirmer test in assessment of salivary flow rate among patients on antidepressants: a comparative study. J Int Soc Prev Community Dent.. 2021;11:287-93.
- [CrossRef] [PubMed] [PubMed Central] [Google Scholar]
- Eight-month follow-up of olfactory and gustatory dysfunctions in recovered COVID-19 patients. Am J Otolaryngol.. 2021;42:103065.
- [CrossRef] [PubMed] [PubMed Central] [Google Scholar]
- Oral manifestations in COVID-19 patients: An observational study. J Family Med Prim Care.. 2022;11:1000-5.
- [CrossRef] [PubMed] [PubMed Central] [Google Scholar]
- Post-COVID-19 patients suffer from chemosensory, trigeminal, and salivary dysfunctions. Sci Rep.. 2024;14:3455.
- [CrossRef] [PubMed] [PubMed Central] [Google Scholar]
- Epithelial cells lining salivary gland ducts are early target cells of severe acute respiratory syndrome coronavirus infection in the upper respiratory tracts of rhesus macaques. J Virol.. 2011;85:4025-30.
- [CrossRef] [PubMed] [PubMed Central] [Google Scholar]
- The pivotal role of TMPRSS2 in coronavirus disease 2019 and prostate cancer. Future Oncol.. 2020;16:2029-33.
- [CrossRef] [PubMed] [PubMed Central] [Google Scholar]
- Exploring salivary diagnostics in COVID-19: A scoping review and research suggestions. BDJ Open.. 2021;7:8.
- [CrossRef] [PubMed] [PubMed Central] [Google Scholar]
- The impact of coronavirus infectious disease 19 (COVID-19) on oral health. Oral Dis.. 2021;27:703-6.
- [CrossRef] [PubMed] [PubMed Central] [Google Scholar]
- Characterization and pathogenic speculation of xerostomia associated with COVID-19: A narrative review. Dent J (Basel).. 2021;9:130.
- [CrossRef] [PubMed] [PubMed Central] [Google Scholar]
- Risk of long COVID associated with delta versus omicron variants of SARS-CoV-2. Lancet.. 2022;399:2263-4.
- [CrossRef] [PubMed] [PubMed Central] [Google Scholar]
- Risk factors, hyposalivation and impact of xerostomia on oral health-related quality of life. Braz Oral Res.. 2017;31:e14.
- [CrossRef] [PubMed] [Google Scholar]