Smell Status in Children Infected with SARS-CoV-2

A Study on the Impact of the COVID-19 Pandemic on the Aetiology of Paediatric Olfactory Dysfunction

INTRODUCTION

Although previous studies have examined olfactory dysfunction in children, the novel coronavirus SARS-CoV-2 has certainly had an unprecedented effect on their olfaction, which could not be taken into consideration. The aim of this report was to present data on the epidemiology of olfactory dysfunction during the pandemic and compare this dataset with a pre-pandemic set. We hypothesized an increase in URTI-related olfactory dysfunction.

METHODS

Data of paediatric patients consulting a smell and taste clinic between March 2020 and June 2022 were retrospectively analysed. The frequency of major causes of olfactory dysfunction was examined and compared with three subsets of an older dataset.

RESULTS

A total of 52 patients were included in the analysis. Most children presented with olfactory dysfunction due to upper respiratory tract infection (URTI) (52%). Congenital olfactory dysfunction was present in 34% of cases. Sinonasal disorders and idiopathic cases accounted for 6 and 4%, respectively, whereas head trauma was the least common cause (2%). This was in contrast with the results of the older set. The frequency of URTI-related olfactory dysfunction increased significantly. The frequency of head-trauma-related or congenital olfactory dysfunction showed marked reductions. There were no significant differences regarding the other aetiologies between our patient cohort and the three subsets.

CONCLUSION

The COVID-19 pandemic has resulted in differences regarding the prevalence of aetiologies between our dataset and the subsets of pre-pandemic times. The surge of the frequency of URTI-related olfactory dysfunction may be ascribed to a novel pathomechanism involving sustentacular cells in the olfactory epithelium.

Subjective Smell Disturbances in Children with Sars-Cov-2 or Other Viral Infections do not Correspond with Olfactory Test Results

BACKGROUND

Olfactory dysfunction associated with SARS-CoV-2 infection in children has not been verified by a validated olfactory test. We aimed to determine whether these complaints are objectifiable (test-based hyposmia), how often they occur during acute SARS-CoV-2 infection compared to other upper respiratory tract infections (URTI), as well as in children recovered from COVID-19 compared to children with long COVID.

METHODS

Olfactory testing (U-sniff test; hyposmia<8 points) and survey-based symptom assessments were performed in 434 children (5-17 years; 04/2021-06/2022). 186 symptom-free children served as controls. Of the children with symptoms of acute respiratory tract infection, SARS-CoV-2 PCR test results were positive in 45 and negative in 107 children (URTI group). Additionally, 96 children were recruited at least 4 weeks (17.6±15.2 weeks) after COVID-19, of whom 66 had recovered and 30 had developed long COVID.

RESULTS

Compared to controls (2.7%), hyposmia frequency was increased in all other groups (11-17%, p<0.05), but no between-group differences were observed. Only 3/41 children with hyposmia reported complaints, whereas 13/16 children with complaints were normosmic, with the largest proportion being in the long-COVID group (23%, p<0.05).

CONCLUSION

Questionnaires are unsuitable for assessing hyposmia frequency in children. Olfactory complaints and hyposmia are not specific for SARS-CoV-2 infection. The number of complaints in the long-COVID group could result from aversive olfactory perception, which is undetectable with the U-sniff test.

How does post COVID differ from other post-viral conditions in childhood and adolescence (0-20 years old)? A systematic review

Background

Post Coronavirus disease (COVID) and other post-viral infection syndromes present an overlap of pathogenesis, onset, progression, and symptom profile. We aimed to systematically describe studies on post-viral conditions and determine the entity of post COVID compared to other post-viral conditions in children.

Methods

We conducted a systematic search of the Embase, MEDLINE, Cochrane Library, and GoogleScholar databases (January 1946-3 November 2023), according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. The main outcomes were differences in condition duration, symptom type, and development of chronic symptoms. This systematic review was registered on PROSPERO (CRD42023401789).

Findings

35/5051 studies were included, with 42,934 children, adolescents and young adults (0-20 years old) overall. Twenty-eight studies focused on post COVID symptoms, followed by five papers on Respiratory Syncytial Virus (RSV) and Rhinovirus, one study on Epstein-Barr Virus (EBV), and one on gastrointestinal viruses. Studies on post COVID mainly reported data on older children/adolescents, describing long-lasting symptoms, including fatigue, neurologic, cardiorespiratory, musculoskeletal, mental health, and gastrointestinal symptoms. The maximum described symptoms duration was eighteen months, with an average follow-up of seven months. The development of chronic symptoms was reported by 30 studies (93.8%) for 10,473/28,474 patients (36.8%). Recovery was achieved in 18,001/28,474 cases (63.2%). The study on EBV reported persistent fatigue in adolescents for a similar duration (6 months, 46% chronic). Studies on RSV and Rhinovirus were mainly done in children under three years, with development of recurrent wheezing (up to 3 years).

Interpretation

Post-viral fatigue was a shared feature between post COVID and post EBV conditions. A better understanding of post COVID as a unique condition, sharing features with other post-viral syndromes, is needed. The healthcare burden and socio-economic consequences for children and their families warrant further investigation and development of appropriate healthcare management plans. The foremost requirement is the establishment of consistent and shareable definitions, as well as a consensus on outcomes, to effectively evaluate follow-up and quantify the burden of different viral infections.

Funding

EU Horizon, EDCTP, NIH.

COVID-19 associated anosmia in pediatric patients: subject publications review

OBJECTIVE

Aim: To review the publications subject to the problem of COVID-19 associated anosmia incidence in pediatric patients as well as its pathogenesis, diagnostics, treatment and recovery. The peculiarity of pediatric COVID-19 anosmia is due to children accounting for very low percentage of COVID-19 patients (comparing to one in adults), mostly with milder course of the disease. Awareness of anosmia and its proper diagnostics is crucial in children and adolescents, considering it can be the only manifestation in COVID-19 positive pediatric patients.

PATIENTS AND METHODS

Materials and Methods: In order to achieve this goal a meta-analysis of information from databases followed by statistical processing and generalisation of the obtained data was carried out.

CONCLUSION

Conclusions: Publications on COVID-19 anosmia in children and adolescents are less numerous than those concerning adult patients, so it is important to use every single trustworthy one. Anosmia/ageusia may be the only symptom, early identifier and the strongest predictor of COVID-19 infection in pediatric patients. Prospects for further scientific researches. Further researches regarding differential diagnostics of COVID-19 and other infections, including seasonal influenza, manifesting with both olfactory and taste dysfunction as well as anosmia diagnostics in children and adolescents with autistic spectrum and different types of mental disorders are possible.

[Adaptation for use In Russia of the extended odor identification Sniffin' Sticks test]

The psychophysical Sniffin' Sticks test, which includes an odor identification test, is the gold standard for assessing the sense of smell in clinical and scientific practice. A necessary requirement for the odor identification test is a close familiarity with the odors used by the inhabitants of the region in which it is used. We studied 77 healthy volunteers and 51 patients with olfactory dysfunction and we found that Russians are not familiar with the three smells from the test (licorice, turpentine and anise) and are completely unfamiliar with the one proposed alternative answer (chives). Moreover, four odors demonstrated very low recognition (less than 75%). The test has been adapted for the use In Russia. In the booklet, licorice is replaced by cough syrup, turpentine by paint thinner, and chives by bay leaf. For odors with low recognition (lemon, apple, pineapple), the alternative fruity odors in the booklet were replaced with more contrasting ones. Based on the data obtained, we are going to develop a domestic version of the odor identification test.

Olfactory disorders in childhood: A comparative study of olfaction in children with adenoid hyperplasia versus a control group and the postoperative effects of adenoidectomy with respect to olfactory ability

PURPOSE

Hyposmia in childhood is poorly characterized. The "U-Sniff Test", validated for children with anosmia, can be used to objectify olfactory impairment but has not been used to distinguish between hyposmia and normosmia. Therefore, we investigated children with enlarged adenoids with respect to hyposmia, its correlation with adenoid size, and the sensitivity of questionnaires to predict olfactory impairment.

METHODS

In a prospective comparison, olfaction was assessed by "U-Sniff Test" (score 0-12; <8 hyposmia) in 41 children (5-18 years) with adenoid hyperplasia and compared with 196 children without any respiratory affection (control) after exclusion of previous SARS-Cov2-infection from December 2020 to December 2021. ENT-related complaints were collected using a self-designed questionnaire. We were able to include 13 children in a follow-up examination to compare preoperative performance in the "U-Sniff Test" with postoperative outcome after adenoidectomy.

STATISTICS

chi-square-test (p < 0.05), odds-ratio, Spearman's rho, ROC-, cluster analysis.

RESULTS

Severe hyposmia was present in 36.6% of children with adenoid-hyperplasia compared to 3.1% of the control-group. Adenoid-children scored significantly more often between 8 and 10 points (58.5%) than the control (31.6%; p < 0.01). Adenoid size and olfactory performance correlate significantly (r: 0.83; CI -0.89 … -0.72). Hyposmia in the adenoid group is characterized predominately by loss of the odors banana, butter and rose. None of children with hyposmia or parents reported impaired olfactory performance. Postoperatively, olfactory function improved significantly in 85% of cases (p 0.01, SD ± 1.71, Δ3.54points).

CONCLUSION

Questionnaires are insufficient to detect hyposmia in this cohort. In contrast, the "U-Sniff Test" detects even reduced olfactory performance without reaching the cut-off value, which represents the majority of test results in the adenoid group. Therefore, we recommend the classification of moderate hyposmia (8-10 points) to be included for our study population.

Long COVID in Children: A Multidisciplinary Review

Long COVID syndrome has emerged as a long-lasting consequence of acute SARS-CoV-2 infection in adults. In addition, children may be affected by Long COVID, with potential clinical issues in different fields, including problems in school performance and daily activities. Yet, the pathophysiologic bases of Long COVID in children are largely unknown, and it is difficult to predict who will develop the syndrome. In this multidisciplinary clinical review, we summarise the latest scientific data regarding Long COVID and its impact on children. Special attention is given to diagnostic tests, in order to help the physicians to find potential disease markers and quantify impairment. Specifically, we assess the respiratory, upper airways, cardiac, neurologic and motor and psychological aspects. Finally, we also propose a multidisciplinary clinical approach.

Prevalence and risk factor for long COVID in children and adolescents: A meta-analysis and systematic review

BACKGROUND

Millions of COVID-19 pediatric survivors are facing the risk of long COVID after recovery from acute COVID-19. The primary objective of this study was to systematically review the available literature and determine the pooled prevalence of, and risk factors for long COVID among the pediatric survivors.

METHODS

Studies that assessed the prevalence of, or risk factors associated with long COVID among pediatric COVID-19 survivors were systematically searched in PubMed, Embase, and Cochrane Library up to December 11th, 2022. Random effects model was performed to estimate the pooled prevalence of long COVID among pediatric COVID-19 patients. Subgroup analyses and meta-regression on the estimated prevalence of long COVID were performed by stratification with follow-up duration, mean age, sex ratio, percentage of multisystem inflammatory syndrome, hospitalization rate at baseline, and percentage of severe illness.

RESULTS

Based on 40 studies with 12,424 individuals, the pooled prevalence of any long COVID was 23.36 % ([95 % CI 15.27-32.53]). The generalized symptom (19.57 %, [95 % CI 9.85-31.52]) was reported most commonly, followed by respiratory (14.76 %, [95 % CI 7.22-24.27]), neurologic (13.51 %, [95 % CI 6.52-22.40]), and psychiatric (12.30 %, [95% CI 5.38-21.37]). Dyspnea (22.75 %, [95% CI 9.38-39.54]), fatigue (20.22 %, [95% CI 9.19-34.09]), and headache (15.88 %, [95 % CI 6.85-27.57]) were most widely reported specific symptoms. The prevalence of any symptom during 3-6, 6-12, and> 12 months were 26.41 % ([95 % CI 14.33-40.59]), 20.64 % ([95 % CI 17.06-24.46]), and 14.89 % ([95 % CI 6.09-26.51]), respectively. Individuals with aged over ten years, multisystem inflammatory syndrome, or had severe clinical symptoms exhibited higher prevalence of long COVID in multi-systems. Factors such as older age, female, poor physical or mental health, or had severe infection or more symptoms were more likely to have long COVID in pediatric survivors.

CONCLUSIONS

Nearly one quarter of pediatric survivors suffered multisystem long COVID, even at 1 year after infection. Ongoing monitoring, comprehensive prevention and intervention is warranted for pediatric survivors, especially for individuals with high risk factors.

Association of anosmia and neutralizing antibody production in adolescents with SARS-CoV-2

BACKGROUND

To monitor olfactory/gustatory dysfunction and its relationship to SARS-CoV-2 IgG antibody responses in an adolescent population.

METHODS

Adolescents with changes in olfactory/gustatory functions were enrolled in a 15-month study. The patients were evaluated with 1) SNOT-22, 2) pediatric smell wheel, and 3) SARS-CoV-2 antibody testing. The relationship between these scores and length of anosmia, and the amount of SARS-CoV-2 IgG antibodies were assessed. A brain MRI was performed in cases of persistent special sensory symptoms.

RESULTS

Eighteen patients were identified with smell and/or taste complaints. Most of the patients were female (67%) and median age was 15 years (range 11-17). Twelve patients had prior SARS-CoV-2 PCR testing, with only five patients with a positive result. The median SNOT-22 score was 16 (range 0-52) and the median smell wheel score was 6.5 (range 1-11). Patients with taste difficulty were more likely to have a score less than eight. 78% of the patients tested positive for antibodies and there was a strong negative correlation between smell wheel score and antibody level (Spearman, ρ = -0.798, p = 0.002). Five patients underwent MRI scan, and all resulted as normal olfactory bulb structures. 66% received nasal corticosteroids. 11 patients presented in follow up.

CONCLUSIONS

Adolescents presenting to a pediatric ENT clinic during the SARS-CoV-2 pandemic were likely to have prolonged (>6 weeks) symptoms of SARS-CoV-2. The majority do not report positive PCR testing result but do report systemic symptoms including anosmia. This suggests that anosmia may be both a late and prolonged symptom of SARS-CoV-2.

Olfactory testing as COVID-19 screening in school children; A prospective cross-sectional study

BACKGROUND

Little is known about olfactory changes in pediatric COVID-19. It is possible that children under-report chemosensory changes on questionnaires, similar to reports in adults. Here, we aim to describe COVID-19-related olfactory dysfunction in outpatient children. We hypothesized that children with COVID-19 will demonstrate abnormal olfaction on smell-identification testing at a higher rate than children with negative COVID-19 testing.

METHODS

A prospective cross-sectional study was undertaken from June 2020-June 2021 at a tertiary care pediatric hospital. A consecutive sample of 205 outpatients aged 5-21 years undergoing severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) PCR testing were approached for this study. Patients with prior olfactory dysfunction were excluded. Participants were given a standard COVID-19 symptom questionnaire, a Smell Identification Test (SIT) and home-odorant-based testing within 2 weeks of COVID-19 testing. Prior to study enrollment, power calculation estimated 42 patients to determine difference in rates of SIT results between groups. Data were summarized with descriptive statistics.

RESULTS

Fifty-one patients underwent smell identification testing (23 positive (45%) and 28 negative (55%) for COVID-19; mean age 12.7 years; 60% female). 92% of all patients denied subjective change in their sense of smell or taste but only 58.8% were normosmic on testing. There was no difference in screening questionnaires or SIT scores between COVID-19 positive and negative groups.

CONCLUSIONS

Unlike adults, there was no statistical difference in olfactory function between outpatient COVID-19 positive and negative children. Our findings suggest a discrepancy between objective and patient-reported olfactory function in pediatric patients, and poor performance of current screening protocols at detecting pediatric COVID-19.

Long COVID in children and adolescents

PURPOSE OF REVIEW

Although acute COVID-19 has been milder in children and young people compared with adults, there is a concern that they may suffer persistent symptoms. There is a need to define the clinical phenotype, determine those most at risk, the natural course of the condition and evaluate preventive and therapeutic strategies for both mental health and physical symptoms.

RECENT FINDINGS

More recent studies with control groups reported a lower prevalence of persistent symptoms in children and young people exposed to SARS-CoV-2. A systematic review and meta-analysis found that the frequency of the majority of reported persistent symptoms is similar in SARS-CoV-2 positive cases and controls. Children and young people infected with SARS-COV-2 had small but significant increases in persisting cognitive difficulties, headache and loss of smell. Factors associated with persisting, impairing symptoms include increased number of symptoms at the time of testing, female sex, older age, worse self-rated physical and mental health, and feelings of loneliness preinfection.

SUMMARY

This review highlights the importance of a control group in studies following SARS-CoV-2 infection, the need for case definitions and research to understand the outcomes of long COVID in children and young people.

Robustness of reported postacute health outcomes in children with SARS-CoV-2 infection: a systematic review

OBJECTIVE

To systematically assess the robustness of reported postacute SARS-CoV-2 infection health outcomes in children.

METHODS

A search on PubMed and Web of Science was conducted to identify studies published up to 22 January 2022 that reported on postacute SARS-CoV-2 infection health outcomes in children (<18 years) with follow-up of ≥2 months since detection of infection or ≥1 month since recovery from acute illness. We assessed the consideration of confounding bias and causality, as well as the risk of bias.

RESULTS

21 studies including 81 896 children reported up to 97 symptoms with follow-up periods of 2.0-11.5 months. Fifteen studies had no control group. The reported proportion of children with post-COVID syndrome was between 0% and 66.5% in children with SARS-CoV-2 infection (n=16 986) and between 2.0% and 53.3% in children without SARS-CoV-2 infection (n=64 910). Only two studies made a clear causal interpretation of an association between SARS-CoV-2 infection and the main outcome of 'post-COVID syndrome' and provided recommendations regarding prevention measures. The robustness of all 21 studies was seriously limited due to an overall critical risk of bias.

CONCLUSIONS

The robustness of reported postacute SARS-CoV-2 infection health outcomes in children is seriously limited, at least in all the published articles we could identify. None of the studies provided evidence with reasonable certainty on whether SARS-CoV-2 infection has an impact on postacute health outcomes, let alone to what extent. Children and their families urgently need much more reliable and methodologically robust evidence to address their concerns and improve care.

COVID-19, Anosmia, and Allergies: Is There a Relationship? A Pediatric Perspective

Background: Between June and July 2020, we evaluated children and adolescents concerning post-infection surveillance after a COVID-19 positivity during the lockdown. We aimed to assess whether the anamnestic presence of allergies could correlate with the presence of SARS-CoV-2 symptoms, and in particular with anosmia. Material and methods: For each patient, we collected anamnestic data, the presence of allergies documented by performing skin prick tests, and COVID-19 symptoms. Then, if over six years of age, each patient underwent an active anterior rhinomanometry. Results: A total of 296 patients were enrolled, of whom 105 (35.4%) reported allergies. Considering COVID-19 symptoms, 74 subjects (25%) presented an asymptomatic form, 222 (75%) reported symptoms, and anosmia recurred in 60 subjects (27.03%). A statistically significant relationship was found between allergies and symptomatic COVID-19 (p = 0.042), allergies, and anosmia (p = 0.05), and allergies and anosmia in males (p = 0.007). Moreover, anosmic patients presented a higher body mass index, older age, and a longer COVID-19 duration with statistical significance (p = 0.001, 0.001, 0.006, respectively). Conclusions: Allergic subjects seem to develop symptomatic COVID-19 more frequently and allergies appear to be a protective factor from anosmia’s onset in males.

Post‑COVID‑19 syndrome in children (Review)

The persistence of symptoms for a long time after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is now familiar as post-COVID syndrome (PCS). To the best of our knowledge, the risk of long-term clinical outcomes in children after SARS-CoV-2 infection is still unclear. Unlike in adults, current evidence suggests a lower prevalence of persistent symptoms in children. However, since several studies are characterized by great heterogeneity, it is difficult to accurately estimate the exact incidence of PCS in children. The presence and course of recovery depend on risk factors that are more common in adults than children. Proposed pathophysiological mechanisms in PCS in children include age-dependent immune responses, angiotensin-converting enzyme 2 expression, blood-brain barrier development or social issues affecting children behavior, such as school closure and social isolation. However, further longitudinal studies are required for unanswered issues to be clarified. The aim of the present review is to describe the long-term symptoms per biological system in children, potential risk factors and the role of the immune system in the presence of PCS.

A systematic review and meta-analysis of otorhinolaryngological manifestations of coronavirus disease 2019 in paediatric patients

BACKGROUND

This meta-analysis provides a quantitative measure of the otorhinolaryngological manifestations of coronavirus disease 2019 in children.

METHODS

A structured literature review was carried out using PubMed, Embase and Cochrane Central, employing pertinent search terms. The statistical analysis was performed using Stata version 14.2 software, and the analysed data were expressed as the pooled prevalence of the symptoms with 95 per cent confidence intervals.

RESULTS

The commonest symptoms noted were cough (38 per cent (95 per cent confidence interval = 33-42; I² = 97.5 per cent)), sore throat (12 per cent (95 per cent confidence interval =10-14; I² = 93.7 per cent)), and nasal discharge (15 per cent (95 per cent confidence interval = 12-19; I² = 96.9 per cent)). Anosmia and taste disturbances showed a pooled prevalence of 8 per cent each. Hearing loss, vertigo and hoarseness were rarely reported.

CONCLUSION

Cough, sore throat and nasal discharge were the commonest otorhinolaryngological symptoms in paediatric patients with coronavirus disease 2019. Compared with adults, anosmia and taste disturbances were infrequently reported in children.

Long-COVID in children and adolescents: a systematic review and meta-analyses

The objective of this systematic review and meta-analyses is to estimate the prevalence of long-COVID in children and adolescents and to present the full spectrum of symptoms present after acute COVID-19. We have used PubMed and Embase to identify observational studies published before February 10th, 2022 that included a minimum of 30 patients with ages ranging from 0 to 18 years that met the National Institute for Healthcare Excellence (NICE) definition of long-COVID, which consists of both ongoing (4 to 12 weeks) and post-COVID-19 (≥ 12 weeks) symptoms. Random-effects meta-analyses were performed using the MetaXL software to estimate the pooled prevalence with a 95% confidence interval (CI). Heterogeneity was assessed using I2 statistics. The Preferred Reporting Items for Systematic Reviewers and Meta-analysis (PRISMA) reporting guideline was followed (registration PROSPERO CRD42021275408). The literature search yielded 8373 publications, of which 21 studies met the inclusion criteria, and a total of 80,071 children and adolescents were included. The prevalence of long-COVID was 25.24%, and the most prevalent clinical manifestations were mood symptoms (16.50%), fatigue (9.66%), and sleep disorders (8.42%). Children infected by SARS-CoV-2 had a higher risk of persistent dyspnea, anosmia/ageusia, and/or fever compared to controls. Limitations of the studies analyzed include lack of standardized definitions, recall, selection, misclassification, nonresponse and/or loss of follow-up, and a high level of heterogeneity.

The Challenge of Studying Long COVID: An Updated Review

Accurately determining the risk of long COVID is challenging. Existing studies in children and adolescents have considerable limitations and distinguishing long-term SARS-CoV-2 infection-associated symptoms from pandemic-related symptoms is difficult. Over half of individuals in this age group, irrespective of COVID-19, report physical and psychologic symptoms, highlighting the impact of the pandemic. More robust data is needed to inform policy decisions.

Five-item odorant test as an indicator of COVID-19 infection in a general population

Purpose

To analyze the utility of a 5-item odorant test (U-Smell-It™) in determining COVID-19 status in COVID-19 polymerase chain reaction (PCR)-positive and -negative participants.

Methods

Symptoms, COVID-19 status, and 5-item odorant test results were collected from general population COVID-19 testing in Louisiana (n = 1042), and routine COVID-19 screening of healthcare workers in a nursing home in Florida (n = 278) (ClinicalTrials.gov Identifier: NCT04431908).

Results

In the general population COVID-19 testing site, a cutoff point of ≤2 (0, 1, or 2 correct answers out of 5) achieved sensitivity of 40.0% (95% CI: 26.4%–54.8%) and specificity of 89.2% (95% CI: 87.1%–91.1%) in detecting COVID-19 infection. Within this population, analysis of individuals with no self-reported loss of smell/taste and runny/stuffy nose resulted in sensitivity of 38.1% (95% CI: 18.1%–61.6%) and specificity of 92.3% (95% CI: 89.1%–93.4%), while analysis of individuals with self-reported loss of smell/taste and/or runny/stuffy nose resulted in sensitivity of 41.4% (95% CI: 23.5%–61.1%) and specificity of 82.4% (95% CI: 77.7%–86.5%).

Conclusions

The quick turnaround time, low cost, reduced resource requirement, and ease of administering odorant tests provide many advantages as an indicator sign to help flag a molecular diagnostic COVID-19 test with relatively high specificity. Our results suggest that this odorant testing for olfactory dysfunction may be a viable option in pre-screening COVID-19 infection. This tool has the potential to allow for continued monitoring and surveillance, while helping mitigate surges of COVID-19 variants. Further investigation is warranted to observe the extent to which odorant testing might be applied in a serial testing scenario.

Persistent symptoms following SARS-CoV-2 infection amongst children and young people: A meta-analysis of controlled and uncontrolled studies

BACKGROUND

Data on the long-term impact of SARS-CoV-2 infection in children and young people (CYP) are conflicting. We assessed evidence on long-term post-COVID symptoms in CYP examining prevalence, risk factors, type and duration.

METHODS

Systematic search of published and unpublished literature using 13 online databases between 01/12/2019 and 31/07/2021. Eligible studies reported CYP ≤19 years with confirmed or probable SARS-CoV-2 with any symptoms persisting beyond acute illness. Random effects meta-analyses estimated pooled risk difference in symptom prevalence (controlled studies only) and pooled prevalence (uncontrolled studies also included). Meta-regression examined study characteristics hypothesised to be associated with symptom prevalence. Prospectively registered: CRD42021233153.

FINDINGS

Twenty two of 3357 unique studies were eligible, including 23,141 CYP. Median duration of follow-up was 125 days (IQR 99-231). Pooled risk difference in post-COVID cases compared to controls (5 studies) were significantly higher for cognitive difficulties (3% (95% CI 1, 4)), headache (5% (1, 8)), loss of smell (8%, (2, 15)), sore throat (2% (1, 2)) and sore eyes (2% (1, 3)) but not abdominal pain, cough, fatigue, myalgia, insomnia, diarrhoea, fever, dizziness or dyspnoea. Pooled prevalence of symptoms in post-COVID participants in 17 studies ranged from 15% (diarrhoea) to 47% (fatigue). Age was associated with higher prevalence of all symptoms except cough. Higher study quality was associated with lower prevalence of all symptoms, except loss of smell and cognitive symptoms.

INTERPRETATION

The frequency of the majority of reported persistent symptoms was similar in SARS-CoV-2 positive cases and controls. This systematic review and meta-analysis highlights the critical importance of a control group in studies on CYP post SARS-CoV-2 infection.

Olfactory dysfunction amongst children and adolescents with laboratory confirmed coronavirus disease 2019: a systematic review

BACKGROUND

Despite the rapidly emerging reports of olfactory dysfunction amongst adult patients with coronavirus disease 2019, cases involving children and adolescents are scarcely reported. The literature was reviewed to elucidate olfactory dysfunction amongst children and adolescents with coronavirus disease 2019.

METHODS

A search of the literature published from 1 December 2019 to 30 April 2021 was conducted using four databases, based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and the Cochrane Handbook for Systematic Reviews of Interventions. The search was performed over one month (May 2021).

RESULTS

Only 9 articles were identified, with a total of 316 laboratory confirmed coronavirus disease 2019 positive children and adolescents, of whom 156 reported olfactory dysfunction. Four studies reported olfactory dysfunction based on subjective tests; four studies carried out objective assessment. Most studies reported on olfaction recovery.

CONCLUSION

The literature review revealed an olfactory dysfunction rate of 49 per cent amongst children and adolescents with coronavirus disease 2019. Persistence of olfactory dysfunction was reported in 7.1 per cent of the patients. Further studies involving objective measures need to be carried out in children and adolescents with coronavirus disease 2019.

Prevalence of Smell or Taste Dysfunction Among Children With COVID-19 Infection: A Systematic Review and Meta-Analysis

Background: Smell and taste dysfunctions are common and have been reported as an early indicator of COVID-19. The prevalence of smell and taste dysfunctions among children with COVID-19 varies greatly across studies, which remains to be summarized quantitatively. This review aimed at examining the pooled prevalence of smell or taste dysfunctions among children with COVID-19, summarizing possible causes of the inconsistencies in the current estimates. Methods: Systematic searches of databases were conducted for literature published until 12 January 2021. Statistical analyses were performed using R software, the pooled prevalence was combined using random effects model. The Loney criteria were used for quality assessment. Results: A total of 18 eligible studies were included. The results showed that the pooled prevalence of smell dysfunction among children with COVID-19 was 15.97% (95% CI: 8.18-23.77%), the pooled prevalence of taste dysfunction among children with COVID-19 was 9.20% (95% CI: 4.25-14.16%), the pooled prevalence of smell or taste dysfunction among children with COVID-19 was 15.50% (95% CI: 10.30-20.70%) and the pooled prevalence of smell and taste dysfunction among children with COVID-19 was 20.21% (95% CI: 14.14-26.28%). Higher smell or taste dysfunction rates were associated with being female, younger age, smaller sample size, patients in Asia, and with comorbidities. Conclusions: Evidence suggests that smell or taste dysfunctions were common among children with COVID-19. Further research is needed to identify effective strategies for preventing and treating smell and taste dysfunctions among children with COVID-19.

Modeling the effectiveness of olfactory testing to limit SARS-CoV-2 transmission

A central problem in the COVID-19 pandemic is that there is not enough testing to prevent infectious spread of SARS-CoV-2, causing surges and lockdowns with human and economic toll. Molecular tests that detect viral RNAs or antigens will be unable to rise to this challenge unless testing capacity increases by at least an order of magnitude while decreasing turnaround times. Here, we evaluate an alternative strategy based on the monitoring of olfactory dysfunction, a symptom identified in 76-83% of SARS-CoV-2 infections-including those with no other symptoms-when a standardized olfaction test is used. We model how screening for olfactory dysfunction, with reflexive molecular tests, could be beneficial in reducing community spread of SARS-CoV-2 by varying testing frequency and the prevalence, duration, and onset time of olfactory dysfunction. We find that monitoring olfactory dysfunction could reduce spread via regular screening, and could reduce risk when used at point-of-entry for single-day events. In light of these estimated impacts, and because olfactory tests can be mass produced at low cost and self-administered, we suggest that screening for olfactory dysfunction could be a high impact and cost-effective method for broad COVID-19 screening and surveillance.