Recent anecdotal and scientific reports have provided evidence of a link between COVID-19 and chemosensory impairments such as anosmia. However, these reports have downplayed or failed to distinguish potential effects on taste, ignored chemesthesis, and generally lacked quantitative measurements. Here, we report the development, implementation and initial results of a multi-lingual, international questionnaire to assess self-reported quantity and quality of perception in three distinct chemosensory modalities (smell, taste, and chemesthesis) before and during COVID-19. In the first 11 days after questionnaire launch, 4039 participants (2913 women, 1118 men, 8 other, ages 19-79) reported a COVID-19 diagnosis either via laboratory tests or clinical assessment. Importantly, smell, taste and chemesthetic function were each significantly reduced compared to their status before the disease. Difference scores (maximum possible change ±100) revealed a mean reduction of smell (-79.7 ± 28.7, mean ± SD), taste (-69.0 ± 32.6), and chemesthetic (-37.3 ± 36.2) function during COVID-19. Qualitative changes in olfactory ability (parosmia and phantosmia) were relatively rare and correlated with smell loss. Importantly, perceived nasal obstruction did not account for smell loss. Furthermore, chemosensory impairments were similar between participants in the laboratory test and clinical assessment groups. These results show that COVID-19-associated chemosensory impairment is not limited to smell, but also affects taste and chemesthesis. The multimodal impact of COVID-19 and lack of perceived nasal obstruction suggest that SARS-CoV-2 infection may disrupt sensory-neural mechanisms.

In a preregistered, cross-sectional study we investigated whether olfactory loss is a reliable predictor of COVID-19 using a crowdsourced questionnaire in 23 languages to assess symptoms in individuals self-reporting recent respiratory illness. We quantified changes in chemosensory abilities during the course of the respiratory illness using 0-100 visual analog scales (VAS) for participants reporting a positive (C19+; n=4148) or negative (C19-; n=546) COVID-19 laboratory test outcome. Logistic regression models identified univariate and multivariate predictors of COVID-19 status and post-COVID-19 olfactory recovery. Both C19+ and C19- groups exhibited smell loss, but it was significantly larger in C19+ participants (mean±SD, C19+: -82.5±27.2 points; C19-: -59.8±37.7). Smell loss during illness was the best predictor of COVID-19 in both univariate and multivariate models (ROC AUC=0.72). Additional variables provide negligible model improvement. VAS ratings of smell loss were more predictive than binary chemosensory yes/no-questions or other cardinal symptoms (e.g., fever). Olfactory recovery within 40 days of respiratory symptom onset was reported for ~50% of participants and was best predicted by time since respiratory symptom onset. We find that quantified smell loss is the best predictor of COVID-19 amongst those with symptoms of respiratory illness. To aid clinicians and contact tracers in identifying individuals with a high likelihood of having COVID-19, we propose a novel 0-10 scale to screen for recent olfactory loss, the ODoR-19. We find that numeric ratings ≤2 indicate high odds of symptomatic COVID-19 (4<OR<10). Once independently validated, this tool could be deployed when viral lab tests are impractical or unavailable.

Vitamin D plays crucial roles in neuroprotection and neurodevelopment, and low levels are commonly associated with schizophrenia. We considered if the association was spurious or causal by examining the association of Vitamin D with Leukocyte Telomere Length (LTL), a marker of cellular aging. Vitamin D levels in 22 well-characterized schizophrenia cases were examined with respect to symptoms, cognition, and functioning. LTL was assessed using quantitative polymerase chain reaction (qPCR). The results showed that 91% (20) had deficient or insufficient Vitamin D levels, which were associated with excitement and grandiosity, social anhedonia, and poverty of speech. Sex-specific analyses showed strong associations of hypovitamintosis D to negative symptoms and decreased premorbid adjustment in males, and to lesser hallucinations and emotional withdrawal, but increased anti-social aggression in females. In females LTL was furthermore associated with Vitamin D levels. This study demonstrates a relationship of low vitamin D levels with increased cellular aging in females. It is also the first study to demonstrate potential sex-specific profiles among schizophrenia cases with hypovitaminosis.

BackgroundPost-COVID syndrome is increasingly recognized by the medical community but has not been studied exclusively in young adults. This preliminary report investigates the prevalence and features of protracted symptoms in non-hospitalized university students who experienced mild-to-moderate acute illness.Methods148 students completed an online study to earn research credit for class. Data from COVID-19 positive participants with symptoms ≥28 days (N=22) were compared to those who fully recovered (N=21) and those not diagnosed with COVID-19 (N=58).Results51% of participants who contracted COVID-19 (N=43) experienced symptoms ≥28 days and were classified as having post-COVID syndrome; all but one (96%) were female. During acute illness the post-COVID group, compared to those who fully recovered, experienced significantly more chest pain (64% vs 14%; P=.002), fatigue (86% vs 48%; P=.009), fever (82% vs 48%; P=.02), olfactory impairment (82% vs 52%; P=.04), headaches (32% vs 5%; P<.05), and diarrhea (32% vs 5%; P<.05). Compared to those not diagnosed with COVID-19, the post-COVID syndrome group more frequently experienced exercise intolerance (43% vs. 0%; P<.001), dyspnea (43% vs. 0%; P<.001), chest pain (31% vs 7%; P=.002), olfactory impairment (19% vs 0%; P=.004), lymphadenopathy (19% vs 0%; P=.004), gustatory impairment (14% vs 0%; P=.02), and appetite loss (36% vs 14%; P=.02).InterpretationOur results contradict the perception that this “yet to be defined” post-COVID syndrome predominantly affects middle-aged adults and suggest that exercise intolerance, dyspnea, chest pain, chemosensory impairment, lymphadenopathy, rhinitis, and appetite loss may differentiate post-COVID syndrome from general symptoms of pandemic, age, and academic related stress. These findings are also consistent with previous reports that females are more vulnerable to this post viral syndrome. Large-scale population-based studies are essential to discerning the magnitude and characterization of post-COVID syndrome in young adults as well as more diverse populations.