key: cord-0747635-kco6hj4d
authors: Pieruzzini, R.; Ayala-Grosso, C.; Navas, J. D. J.; Rodriguez, W. C.; Parra, N.; Luque, E.; Sanchez Gago, A.; Gonzalez, S.; Hagobian, A.; Grullon, A.; Diaz, K.; Morales, M.; De Jesus, M.; Pena, S.; Rodriguez, L.; Pena, L.; Asaro, A.; Magris, M.
title: What do we Know about smell and taste dysfunction by SARS-CoV-2.Predictive value of the Venezuelan Olfactory test and RT-PCR analysis in viral infection diagnosis
date: 2020-11-30
journal: nan
DOI: 10.1101/2020.11.25.20238998
sha: 5a1ae251aaa8c4f3881e4a62d89059dd329c06d2
doc_id: 747635
cord_uid: kco6hj4d

Smell and taste disorders are reported very frequently and at an early stage in the evolution of the infectious disease caused by the SARS-CoV-2. These symptoms could be sensitive and specific to establish the condition of the infection, and may suggest the flow of decisions as to further therapy. We asked whether smell and taste impairment are earlier and more sensitive symptoms than the RT-PCR molecular assays for SARS-CoV-2 detection.

of coronavirus was reported in the United Kingdom recently; however, the evidence 72 seems to be circumstantial, because it was found as information provided in social 73 media by subjects who had had this symptom in an isolated fashion. The authors 74 reported 9 cases of sudden anosmia without other associated symptoms in the first 3 75 weeks of the onset of the coronavirus. It is worth mentioning that none of these 76 patients was evaluated with a specific test to determine the presence of the disorder 77

(3). 78

More recently, another study carried out at Hospital L. Sacco in Milan, Italy with 59 79 of the 88 patients of the hospital, established that 33.9% had at least one smell and/or 80 taste disorder and 18.6% had both. In this group of patients, 20.3% had smell 81 symptoms before they were admitted to the hospital and 13.5% during their stay (4). 82

The presence of smell alterations associated with a viral infection is not new in 83 otorhinolaryngology; many viruses may cause olfactory dysfunction due to an 84 inflammatory process of the nasal mucosa and the development of rhinorrhea. Among 85 the viral agents associated with these alterations are rhinovirus, parainfluenza, 86

Epstein-Bar, and some coronavirus (4,5). However, the fact that olfactory dysfunction 87 associated with SARS-CoV-2 is not essentially related to the onset of rhinorrhea and 88 nasal obstruction suggests a different action mechanism. So far, the physiopathology 89 of smell and taste disorders in the SARS-CoV-2 infection is still under scrutiny. 90

One of the most relevant evidences of the action mechanism of coronavirus was 91 reported as a result of an investigation of the olfactory mucosa of mice and analysis of 92 RNA sequences of humans. It found that the 2 genes that express the information for 93 angiotensin-converting enzyme 2 (ACE2) and the host transmembrane serine protease 94 family member II (TMPRSS2) receptors involved in the entry of COV-2 into the cell 95 are expressed in the cells of the respiratory epithelium of the nasal cavity, support 96 cells, Bowman´s glands, microvilli, and stem cells of the olfactory mucosa, but not in 97 the olfactory sensory neurons. This suggests that the olfactory damage mechanism is 98 non-neural in nature. As to the damage to the sense of taste, it appears to be directly 99 on the taste receptor and as the result of the production of cytokines that irritate the 100 trigeminal and glossopharyngeal nerves that transmit sensory signals to the central 101 nervous system (6). Nasopharyngeal swab for SARS-CoV-2 by RT-PCR molecular analysis and detection 136 of SARS-CoV-2 antibodies by rapid diagnostic test (RDT). 137

In this study, patients were followed-up every 3 to 5 days, to verify their overall 138 clinical condition. In addition, smell and taste tests were carried out, blood samples 139 All rights reserved. No reuse allowed without permission. preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. On the basis of identification and discrimination of odors presented to patients, the 170 VOT provides a relative grading scale as follows: Normosmia (8-10), mild hyposmia 171 (6-7), moderate hyposmia (5-4), severe hyposmia (2-3), and anosmia (0-1). 172

The taste test consists in recognizing the 5 universally accepted basic tastes, to wit: 173 All rights reserved. No reuse allowed without permission. preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this this version posted November 30, 2020. ; https://doi.org/10.1101/2020.11.25.20238998 doi: medRxiv preprint sweet, salty, sour, bitter, and umami (11) . One (1) cc of a sample of each taste is 174 placed on the anterior third of the tongue of the patient who has his eyes closed, and 175 after 10 seconds of period, an identification of the sample may occur. If the patient 176 cannot recognize the tastes, he is diagnosed with ageusia, and hypogeusia if the 177 patient recognized up to 4 tastes. informed consent. The current study included participants for which there was full 207 All rights reserved. No reuse allowed without permission. preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this this version posted November 30, 2020. ; https://doi.org/10.1101/2020.11.25.20238998 doi: medRxiv preprint information on multiple SARS-CoV-2 measures and key outcomes, including 208 psychosocial factors, chronic medical conditions, and socio-demographic factors. 209

Descriptive statistics was used in the analysis by age group and type of chemosensory 211 impairment. The predictive value, sensitivity and specificity of diagnostic tests used 212 were calculated on the basis of the Wilson score method using the OpenEpi, version 3 213 software. Diagnostic Test Open code Calculator. 214 Χ 2 -Square tests were used to find the most frequent type of symptom in the SARS-215

CoV-2 infection. We asked whether there is a relationship between the SARS-CoV-2 216 infection and the presence or absence of symptoms; and to evaluate the relationship 217 among type of olfactory disorder, age and gender. In the case of the association 218 between two variables, when the result of the Χ 2 -Square test was positive, that is to 219 say, the variables were dependent on, or associated to one another, a standardized 220 residuals analysis was carried out. This analysis allows to determine in a significant 221 manner which cell or frequency contributed more to the rejection of the null 222 hypothesis in the Χ 2 -Square test. Additionally, it allows to find out which cells 223 deviated significantly from the expected value. Any deviation value higher than ±1.96 224 from the normal distribution is considered significant. 225

Pearson's Χ 2 -Square test and Fisher's exact test were used to evaluate between-group 226 differences in two categorical variables. 227 Χ 2 -Square tests and standardized residuals analyses were carried out in R with the 228 chisq.test function of the stats. package (12). 229

The most frequent age group among study subjects was the 25 -38 years old, and 231 there were more male (54.90 %) than female (45.09 %) subjects; average age of the 232 population was 33.63 ± 5 years old (Table 2) The observation of a higher incidence of olfactory and taste disorders together with a 241 All rights reserved. No reuse allowed without permission. preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this this version posted November 30, 2020. ; https://doi.org/10.1101/2020.11.25.20238998 doi: medRxiv preprint positive molecular diagnostic suggested that the dysfunction of these senses could 242 happen before or to a greater extent than the expression of viral genes evidenced by 243 the RT-PCR test, and this could imply that the physiology of the chemosensory 244 system is more susceptible to SARS-CoV-2 infection. 245

To assess this observation, molecular tests were performed on the 275 subjects who 246 had gotten smell and taste tests. It was found that 144 subjects were RT-PCR+ for 247 SARS-CoV-2 while 131 were RT-PCR-for SARS-CoV-2. In the RT The frequency of subjects in the SyMVOTT+, SyMVOTT-and ASYM groups as a 261 function of the presence of chemosensory symptoms and the positive molecular test 262 results was heterogeneous (X 2 = 9.19, gl = 2, p < 0.05), which suggests that the type 263 of symptoms and their association with chemosensory dysfunction is different in the 264 case of SARS-CoV-2 infection. This is consistent with what was observed in the 265 analysis of standardized residuals, since, in the SARS-CoV-2 infection, the 266 chemosensory dysfunction is very frequent and, in this sample, very few subjects that 267 presented with the disease were asymptomatic (Table 4 .1, Figure 1 ). On the other 268 hand, olfactory and taste disorders are infrequent in the general population (Tables 3  269   and 3.1) . 270

When the frequency of patients with olfactory and taste disorders that were diagnosed 272 with the VOTT was compared to the RT-PCR tests positive results, the positive 273 predictive value of the VOTT was 61.68%, while the negative predictive value was 274 53.57%. These results suggested that VOTT+ patients had a 0.62 probability of being 275 All rights reserved. No reuse allowed without permission. preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. according to standardized residuals analysis P < 0.05; (Table 6) . 290

The group of VOTT+ patients without any other accompanying symptom (no 291 concomitants), who referred olfactory and taste disorder as their only symptom before 292 the molecular diagnostic and before being admitted to the hospital was 18/97 293 (18.55%) ( Table 7) . When differentiated on the basis of the type of chemosensory 294 dysfunction, 7 presented with olfactory disorder only, 4 of them anosmia, and 3 with 295 mild hyposmia. Combined smell and taste disorders at various degrees were present in 296 10 subjects, and only 1 had hypogeusia. All these findings suggest a disorder 297 variability that may indicate the presence of coronavirus infection and not only the 298 anosmia or the ageusia. In this group of patients, chemosensory disorders were an 299 early biomarker of the coronavirus disease. 300

Chemosensory dysfunction was a symptom in 31.25% of the subjects of the 301 SyVOTT+ group before being admitted to the hospital. In contrast, 68.75% of the 302 patients of the sample that did not declare the disorder before being admitted to the 303 hospital, were positive for olfactory or taste disorder when the VOT and taste test 304 were used. This confirms the need to use a standardized objective taste for detecting 305 the chemosensory disorder during the hospital stay. On the other hand, the onset of 306 the chemosensory dysfunction in the SyVOTT+ group occurred between the 3 rd and 307 5 th day in 70% of the cases. 308 All rights reserved. No reuse allowed without permission. preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this this version posted November 30, 2020. ; https://doi.org/10.1101/2020.11.25.20238998 doi: medRxiv preprint Other associated symptoms in the SyVOTT+ group vary. Among them, headache, 309 myalgia, arthralgia, shivering, odynophagia, and hyporexia in 48% of patients; fever, 310 headache, and general malaise in 31%, dry cough and chest pain in 8% dyspnea, and 311 only fever or myalgia in 8% and 2%, respectively. 312

Similarly, in the SyVOTT-patients, which accounted for 32.98% of the sample, there 313 was fever, headache, myalgia, arthralgia, and shivering in 46.87% of them; headache, 314 arthralgia and myalgia in 15%, as well as chest pain, dyspnea in 15%, rhinorrhea, 315 fever, nasal congestion, and dysphonia in 12.5%; and cough, general malaise, fever, 316 and shivering in 9%. As relates the variety of symptoms in SyVOTT+ and SyVOTT-317 groups, no differences were observed in the frequency of presentation that would 318 warrant an additional classification in the SARS-CoV-2 infection. 319

Age, Gender and VOTT 320

In this study, when the presence of chemosensory dysfunction in the subjects of the 321 sample was taken into account, the frequency was similar among them regardless 322 gender or age (Table 7) . Furthermore, smell and taste disorders combined were 323 present in 40.90% of VOTT+ patients. The severity of the disorder is anosmia and 324 ageusia in 30% of the cases, while mild hyposmia and hypogeusia were observed in 325 59.25% of the cases. The olfactory disorder alone, was present as anosmia (12.12%), 326 severe hyposmia 6.06%, mild hyposmia 25.75%, and moderate hyposmia (6.06%). It evidenced by the VOT test. The average recovery interval was 8 to 10 days, with a 341 All rights reserved. No reuse allowed without permission. preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this this version posted November 30, 2020. ; https://doi.org/10.1101/2020.11.25.20238998 doi: medRxiv preprint minimum of 3 days and a maximum of 20 (Figures 2A and 2B) . Only one patient did 342 not recover the sense of smell during the time of the study. 343

The frequency analysis of the RT-PCR molecular test for SARS- preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this this version posted November 30, 2020. ; https://doi.org/10.1101/2020.11.25.20238998 doi: medRxiv preprint

Anosmia and ageusia were otorhinolaryngological and neurological signs of the 377 coronavirus disease. Currently, the physiopathology of anosmia due to COVID-19 is 378 apparently better understood; however, there is still the question why patients with 379 moderate to severe COVID-19 infection have less olfactory affectation. Findings of 380 this study show that 98% of patients with smell and taste disorders had mild 381 COVID19. These results are in agreement with a recent report of self-described 382 olfactory dysfunction in mild forms of SARS-CoV-2 infection that did not require 383 hospitalization (13). For instance, the chemosensory dysfunction established in this 384 study by means of self-evaluation underestimates the incidence of this symptom; 385 therefore it would be advisable to examine whether anosmia is less prevalent in more 386 severe forms of the infection and, consequently, the mechanism that leads to the 387 physiopathological process that gives rise to this affectation. 388

The definition of a mild or severe form of SARS-CoV-2 infection may imply there is 389 an immune response with more or less contention power thus leading to a milder or 390 more serious viral infection, respectively. This response in the entryway of the virus 391 may also imply that the progression of the infection depends on the time taken by the 392 virus to move towards the upper or lower airways. Therefore, it is possible that, in the 393 mild forms of the coronavirus infection, a more intense and faster immune response 394 will produce more local inflammation that evolves into inflammatory processes 395 involving the neuroepithelium and olfactory bulb. In contrast, in low intensity late 396 immune responses, patients present with mild symptoms in ears, nose and throat; but 397 later, these could also involve higher and lower airways with respiratory compromise 398 (14, 15). 399

These two hypotheses have not been experimentally corroborated, because results 400

show that patients with severe or critical forms have a higher immunoglobulin 401 concentration in the serum and nasal secretions than patients with mild forms; which 402 additionally makes sense, because the severe respiratory compromise has been 403 justified as being a cytokine storm mechanism. 404

Since the beginning of the pandemic, COVID-19 symptoms reports have been about 405 the respiratory tract affectation, with serious and fatal complications in a certain 406 percentage of cases. The first reports involving a nervous system affectation were 407 associated to a sudden decrease in the sense of smell, sometimes accompanied by a 408 decrease in the sense of taste, which patients recovered from regardless whether they 409 All rights reserved. No reuse allowed without permission. preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this this version posted November 30, 2020. ; https://doi.org/10.1101/2020.11.25.20238998 doi: medRxiv preprint had a positive infection outcome or not. Initial reports were based on telephone 410 interviews or online self-assessments by means of a questionnaire. As a result, the 411 incidence of the chemosensory disorder was 19.4% (2); 64% (16); and 85.6% (15). Applying standardized tests to SARS-CoV-2 infected patients has allowed to 422 determine the level of involvement of the sensory function in the progression of the 423 viral pathology. In a previous study, an UPSIT test for the Persian population applied 424 to a reduced number of patients in Iran established that the olfactory disorder is 425 variable, as there was a reduced rate of anosmic subjects (25%), while the largest 426 percentage had moderate and severe microsmia (60%). Therefore, it was suggested 427 that this degree of sensitivity was not enough to be able to consider the smell test as 428 an indicator of the progression of the infection (18). 429

The senses of smell and taste form a physiological system that is affected by COVID-430 19; however, the degree of affectation seems to be mild. This has been shown by the 431 studies carried out using as objective evaluator the chemosensory test of the Clinical 432

Research Center of Connecticut, which has shown, just like Moein et al., findings, 433 that a very small number were anosmic, while most had moderate and mild hyposmia 434 (80%). At the same time, the taste test established that the taste affectation was mild 435 to moderate. All patients maintained a normal degree of discrimination and a 436 subjective overall recovery of 66%; but up to 88% presented with a certain degree of 437 chemosensory disorder (19). 438

In contrast with these results, in this study, the results of several smell and taste tests 439 showed the progressiveness of the disorder and time to recover from the onset of the 440 infection. Contrary to what was seen in prior studies, in our sample, mild hyposmia 441 and anosmia accounted for the highest share with a progressive recovery. The onset of 442 the infection and its evolution allowed to make an evaluation until the recovery of the 443 All rights reserved. No reuse allowed without permission. preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this this version posted November 30, 2020. The presence of asymptomatic SARS-CoV-2 positive patients and the fact that the 475 predictive value of the Venezuelan olfactory test and the basic taste test does not 476 exceed 70% may be hypothetically explained, not only by the time when the 477 All rights reserved. No reuse allowed without permission. preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this this version posted November 30, 2020. ; https://doi.org/10.1101/2020.11.25.20238998 doi: medRxiv preprint investigation began -which was too early with respect to the contagion peak in the 478 country-but also by some social, demographic, and genetic characteristics of the 479 sample studied. It could also be due to the virus mutations that affect certain 480 populations. 481

In this regard, the SARS-CoV-2 spike mutation has been described as supporting organization, and care of patients. Special mention goes to following 511 All rights reserved. No reuse allowed without permission. preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The disposable olfactory test kits were home-made and self-funded by the developers 541 of the VOT as follows: Wilneg Rodriguez, Carlos Velasquez and Rosalinda 542

Pieruzzini. 543 544 All rights reserved. No reuse allowed without permission. preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this this version posted November 30, 2020. ; https://doi.org/10.1101/2020.11.25.20238998 doi: medRxiv preprint 631 632 All rights reserved. No reuse allowed without permission. preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this this version posted November 30, 2020. ; https://doi.org/10.1101/2020.11.25.20238998 doi: medRxiv preprint 637 638 639 preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this this version posted November 30, 2020. ; https://doi.org/10.1101/2020.11.25.20238998 doi: medRxiv preprint

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University Military Hospital "Dr. Carlos Arvelo

Olfactory Test was performed until Olfactory Index Grading reached normosmic 651 value (8-10). A. Each bar represents number of subjects at specific grade of olfaction

Bar symbol represents day of testing (Day 1 -10). B. Each bar represents number of 653 subjects at specific grade of olfaction. Bar symbol represents day of testing

Figure 3. Evolution of RT-PCR molecular analisis under SARS-CoV-2 infection

RT-PCR molecular analysis was performed multiple times to each patient until 658 testing become negative. Each bar represent the number of patients RT-PCR+ 659 (black) and RT-PCR-(white) through time (days of PCR testing)