The association between dietary intakes of zinc, vitamin C and COVID-19 severity and related symptoms: A cross-sectional study.

BACKGROUND: The Coronavirus disease 2019 (COVID-19) pandemic has had a devastating impact on health systems, food supplies, and population health. This is the first study to examine the association between zinc and vitamin C intakes and the risk of disease severity and symptoms among COVID-19 patients. METHODS: This cross-sectional study included 250 recovered COVID-19 patients aged 18-65 years from June to September 2021. Data on demographics, anthropometrics, medical history, and disease severity and symptoms were collected. Dietary intake was evaluated using a web-based, 168-item food frequency questionnaire (FFQ). The severity of the disease was determined using the most recent version of the NIH COVID-19 Treatment Guidelines. Using multivariable binary logistic regression, the association between zinc and vitamin C intakes and the risk of disease severity and symptoms in COVID-19 patients was evaluated. RESULTS: The mean age of participants in this study was 44.1 ± 12.1, 52.4% of them were female, and 46% had a severe form of the disease. Participants with higher zinc intakes had lower levels of inflammatory cytokines, such as C-reactive protein (CRP) (13.6 vs. 25.8 mg/l) and erythrocyte sedimentation rate (ESR) (15.9 vs. 29.3). In a fully adjusted model, a higher zinc intake was also associated with a lower risk of severe disease (OR: 0.43; 95% CI: 0.21, 0.90, P-trend = 0.03). Similarly, participants with higher vitamin C intakes had lower CRP (10.3 vs. 31.5 mg/l) and ESR serum concentrations (15.6 Vs. 35.6) and lower odds of severe disease after controlling for potential covariates (OR: 0.31; 95% CI: 0.14, 0.65, P-trend = <0.01). Furthermore, an inverse association was found between dietary zinc intake and COVID-19 symptoms, such as dyspnea, cough, weakness, nausea and vomiting, and sore throat. Higher vitamin C intake was associated with a lower risk of dyspnea, cough, fever, chills, weakness, myalgia, nausea and vomiting, and sore throat. CONCLUSION: In the current study, higher zinc and vitamin C intakes were associated with decreased odds of developing severe COVID-19 and its common symptoms.

The association between dietary intakes of zinc, vitamin C and COVID-19 severity and related symptoms: A cross-sectional study

Background The Coronavirus disease 2019 (COVID-19) pandemic has had a devastating impact on health systems, food supplies, and population health. This is the first study to examine the association between zinc and vitamin C intakes and the risk of disease severity and symptoms among COVID-19 patients. Methods This cross-sectional study included 250 recovered COVID-19 patients aged 18-65 years from June to September 2021. Data on demographics, anthropometrics, medical history, and disease severity and symptoms were collected. Dietary intake was evaluated using a web-based, 168-item food frequency questionnaire (FFQ). The severity of the disease was determined using the most recent version of the NIH COVID-19 Treatment Guidelines. Using multivariable binary logistic regression, the association between zinc and vitamin C intakes and the risk of disease severity and symptoms in COVID-19 patients was evaluated. Results The mean age of participants in this study was 44.1±12.1, 52.4% of them were female, and 46% had a severe form of the disease. Participants with higher zinc intakes had lower levels of inflammatory cytokines, such as C-reactive protein (CRP) (13.6 vs. 25.8 mg/l) and erythrocyte sedimentation rate (ESR) (15.9 vs. 29.3). In a fully adjusted model, a higher zinc intake was also associated with a lower risk of severe disease (OR: 0.43;95% CI: 0.21, 0.90, P-trend = 0.03). Similarly, participants with higher vitamin C intakes had lower CRP (10.3 vs. 31.5 mg/l) and ESR serum concentrations (15.6 Vs. 35.6) and lower odds of severe disease after controlling for potential covariates (OR: 0.31;95% CI: 0.14, 0.65, P-trend = <0.01). Furthermore, an inverse association was found between dietary zinc intake and COVID-19 symptoms, such as dyspnea, cough, weakness, nausea and vomiting, and sore throat. Higher vitamin C intake was associated with a lower risk of dyspnea, cough, fever, chills, weakness, myalgia, nausea and vomiting, and sore throat. Conclusion In the current study, higher zinc and vitamin C intakes were associated with decreased odds of developing severe COVID-19 and its common symptoms.

Outpatient Treatment of Confirmed COVID-19 : A Living, Rapid Review for the American College of Physicians.

BACKGROUND: Clinicians and patients want to know the benefits and harms of outpatient treatment options for SARS-CoV-2 infection. PURPOSE: To assess the benefits and harms of 12 different COVID-19 treatments in the outpatient setting. DATA SOURCES: Epistemonikos COVID-19 L·OVE Platform, searched on 4 April 2022. STUDY SELECTION: Two reviewers independently screened abstracts and full texts against a priori-defined criteria. Randomized controlled trials (RCTs) that compared COVID-19 treatments in adult outpatients with confirmed SARS-CoV-2 infection were included. DATA EXTRACTION: One reviewer extracted data and assessed risk of bias and certainty of evidence (COE). A second reviewer verified data abstraction and assessments. DATA SYNTHESIS: The 26 included studies collected data before the emergence of the Omicron variant. Nirmatrelvir-ritonavir and casirivimab-imdevimab probably reduced hospitalizations (1% vs. 6% [1 RCT] and 1% vs. 4% [1 RCT], respectively; moderate COE). Nirmatrelvir-ritonavir probably reduced all-cause mortality (0% vs. 1% [1 RCT]; moderate COE), and regdanvimab probably improved recovery (87% vs. 72% [1 RCT]; moderate COE). Casirivimab-imdevimab reduced time to recovery by a median difference of 4 days (10 vs. 14 median days [1 RCT]; high COE). Molnupiravir may reduce all-cause mortality, sotrovimab may reduce hospitalization, and remdesivir may improve recovery (low COE). Lopinavir-ritonavir and azithromycin may have increased harms, and hydroxychloroquine may result in lower recovery rates (low COE). Other treatments had insufficient evidence or no statistical difference in efficacy and safety versus placebo. LIMITATION: Many outcomes had few events and small samples. CONCLUSION: Some antiviral medications and monoclonal antibodies may improve outcomes for outpatients with mild to moderate COVID-19. However, the generalizability of the findings to the currently dominant Omicron variant is limited. PRIMARY FUNDING SOURCE: American College of Physicians. (PROSPERO: CRD42022323440).

Elimination, substitution, engineering, and administrative interventions to reduce the risk of SARS‐CoV‐2 infection in healthcare workers

Objectives This is a protocol for a Cochrane Review (intervention). The objectives are as follows: To assess the effectiveness of interventions to prevent exposure to SARS‐CoV‐2 among HCWs compared to any control intervention or no intervention.

Workplace interventions to reduce the risk of SARS‐CoV‐2 infection outside of healthcare settings

Objectives This is a protocol for a Cochrane Review (intervention). The objectives are as follows: To assess the benefits and harms of interventions in non‐healthcare‐related workplaces to reduce the risk of SARS‐CoV‐2 infection relative to other interventions or no intervention.

Workplace interventions to reduce the risk of SARS-CoV-2 infection outside of healthcare settings.

BACKGROUND: Although many people infected with SARS-CoV-2 (severe acute respiratory syndrome coronavirus-2) experience no or mild symptoms, some individuals can develop severe illness and may die, particularly older people and those with underlying medical problems. Providing evidence-based interventions to prevent SARS-CoV-2 infection has become more urgent with the spread of more infectious SARS-CoV-2 variants of concern (VoC), and the potential psychological toll imposed by the coronavirus disease 2019 (COVID-19) pandemic.   Controlling exposures to occupational hazards is the fundamental method of protecting workers. When it comes to the transmission of viruses, such as SARS-CoV-2, workplaces should first consider control measures that can potentially have the most significant impact. According to the hierarchy of controls, one should first consider elimination (and substitution), then engineering controls, administrative controls, and lastly, personal protective equipment (PPE). OBJECTIVES: To assess the benefits and harms of interventions in non-healthcare-related workplaces to reduce the risk of SARS-CoV-2 infection relative to other interventions, or no intervention. SEARCH METHODS: We searched MEDLINE, Embase, Web of Science, Cochrane COVID-19 Study Register, the Canadian Centre for Occupational Health and Safety (CCOHS), Clinicaltrials.gov, and the International Clinical Trials Registry Platform to 14 September 2021. We will conduct an update of this review in six months. SELECTION CRITERIA: We included randomised control trials (RCT) and planned to include non-randomised studies of interventions. We included adult workers, both those who come into close contact with clients or customers (e.g. public-facing employees, such as cashiers or taxi drivers), and those who do not, but who could be infected by co-workers. We excluded studies involving healthcare workers. We included any intervention to prevent or reduce workers' exposure to SARS-CoV-2 in the workplace, defining categories of intervention according to the hierarchy of hazard controls, i.e. elimination; engineering controls; administrative controls; personal protective equipment. DATA COLLECTION AND ANALYSIS: We used standard Cochrane methods. Our primary outcomes were incidence rate of SARS-CoV-2 infection (or other respiratory viruses), SARS-CoV-2-related mortality, adverse events, and absenteeism from work. Our secondary outcomes were all-cause mortality, quality of life, hospitalisation, and uptake, acceptability, or adherence to strategies. We used the Cochrane RoB 2 tool to assess the risk of bias, and GRADE methods to assess the certainty of evidence for each outcome. MAIN RESULTS: Elimination of exposure interventions We included one study examining an intervention that focused on elimination of hazards. This study is an open-label, cluster-randomised, non-inferiority trial, conducted in England in 2021. The study compared standard 10-day self-isolation after contact with an infected person to a new strategy of daily rapid antigen testing and staying at work if the test is negative (test-based attendance). The trialists hypothesised that this would lead to a similar rate of infections, but lower COVID-related absence. Staff (N = 11,798) working at 76 schools were assigned to standard isolation, and staff (N = 12,229) at 86 schools to the test-based attendance strategy.  The results between test-based attendance and standard 10-day self-isolation were inconclusive for the rate of symptomatic PCR-positive SARS-COV-2 infection rate ratio ((RR) 1.28, 95% confidence interval (CI) 0.74 to 2.21; 1 study, very low-certainty evidence)). The results between test-based attendance and standard 10-day self-isolation were inconclusive for the rate of any PCR-positive SARS-COV-2 infection (RR 1.35, 95% CI 0.82 to 2.21; 1 study, very low-certainty evidence). COVID-related absenteeism rates were 3704 absence days in 566,502 days-at-risk (6.5 per 1000 days at risk) in the control group and 2932 per 539,805 days-at-risk (5.4 per 1000 days at risk) in the intervention group (RR 0.83; 95% CI 0.55 to 1.25). The certainty of the evidence was downgraded to low, due to imprecision. Uptake of the intervention was 71 % in the intervention group, but not reported for the control intervention.  The trial did not measure other outcomes, SARS-CoV-2-related mortality, adverse events, all-cause mortality, quality of life, and hospitalisation. We found one ongoing RCT about screening in schools, using elimination of hazard strategies. Personal protective equipment We found one ongoing non-randomised study on the effects of closed face shields to prevent COVID-19 transmission. Other intervention categories We did not find studies in the other intervention categories. AUTHORS' CONCLUSIONS: We are uncertain whether a test-based attendance policy affects rates of PCR-postive SARS-CoV-2 infection (any infection; symptomatic infection) compared to standard 10-day self-isolation amongst school and college staff. Test-based attendance policy may result in little to no difference in absence rates compared to standard 10-day self-isolation. As a large part of the population is exposed in the case of a pandemic, an apparently small relative effect that would not be worthwhile from the individual perspective may still affect many people, and thus, become an important absolute effect from the enterprise or societal perspective.  The included study did not report on any other primary outcomes of our review, i.e. SARS-CoV-2-related mortality and adverse events. No completed studies were identified on any other interventions specified in this review, but two eligible studies are ongoing. More controlled studies are needed on testing and isolation strategies, and working from home, as these have important implications for work organisations.

Crowdsourcing the identification of studies for COVID-19-related Cochrane Rapid Reviews.

BACKGROUND: Utilisation of crowdsourcing within evidence synthesis has increased over the last decade. Crowdsourcing platform Cochrane Crowd has engaged a global community of 22,000 people from 170 countries. The COVID-19 pandemic presented an opportunity to engage the community and keep up with the exponential output of COVID-19 research. AIMS: To test whether a crowd could accurately assess study eligibility for reviews under time constraints. OUTCOME MEASURES: time taken to complete each task, time to produce required training modules, crowd sensitivity, specificity and crowd consensus. METHODS: We created four crowd tasks, corresponding to four Cochrane COVID-19 Rapid Reviews. The search results of each were uploaded and an interactive training module was developed for each task. Contributors who had participated in another COVID-19 task were invited to participate. Each task was live for 48-h. The final inclusion and exclusion decisions made by the core author team were used as the reference standard. RESULTS: Across all four reviews 14,299 records were screened by 101 crowd contributors. The crowd completed each screening task within 48-h for three reviews and in 52 h for one. Sensitivity ranged from 94% to 100%. Four studies, out of a total of 109, were incorrectly rejected by the crowd. However, their absence ultimately would not have altered the conclusions of the reviews. Crowd consensus ranged from 71% to 92% across the four reviews. CONCLUSION: Crowdsourcing can play a valuable role in study identification and offers willing contributors the opportunity to help identify COVID-19 research for rapid evidence syntheses.

Surgical or radiological treatment for varicoceles in subfertile men.

BACKGROUND: Varicoceles are associated with male subfertility; however, the mechanisms by which varicoceles affect fertility have yet to be satisfactorily explained. Several treatment options exist, including surgical or radiological treatment, however the safest and most efficient treatment remains unclear.  OBJECTIVES: To evaluate the effectiveness and safety of surgical and radiological treatment of varicoceles on live birth rate, adverse events, pregnancy rate, varicocele recurrence, and quality of life amongst couples where the adult male has a varicocele, and the female partner of childbearing age has no fertility problems. SEARCH METHODS: We searched the following databases on 4 April 2020: the Cochrane Gynaecology and Fertility Group Specialised Register, CENTRAL, MEDLINE, Embase, PsycINFO, and CINAHL. We also searched the trial registries and reference lists of articles. SELECTION CRITERIA: We included randomised controlled trials (RCTs) if they were relevant to the clinical question posed and compared different forms of surgical ligation, different forms of radiological treatments, surgical treatment compared to radiological treatment, or one of these aforementioned treatment forms compared to non-surgical methods, delayed treatment, or no treatment. We extracted data if the studies reported on live birth, adverse events, pregnancy, varicocele recurrence, and quality of life. DATA COLLECTION AND ANALYSIS: Screening of abstracts and full-text publications, alongside data extraction and 'Risk of bias' assessment, were done dually using the Covidence software. When we had sufficient data, we calculated random-effects (Mantel-Haenszel) meta-analyses; otherwise, we reported results narratively. We used the I2 statistic to analyse statistical heterogeneity. We planned to use funnel plots to assess publication bias in meta-analyses with at least 10 included studies. We dually rated the risk of bias of studies using the Cochrane 'Risk of bias' tool, and the certainty of evidence for each outcome using the GRADE approach. MAIN RESULTS: We identified 1897 citations after de-duplicating the search results. We excluded 1773 during title and abstract screening. From the 113 new full texts assessed in addition to the 10 studies (11 references) included in the previous version of this review, we included 38 new studies, resulting in a total of 48 studies (59 references) in the review providing data for 5384 participants. Two studies (three references) are ongoing studies and two studies are awaiting classification. Treatment versus non-surgical, non-radiological, delayed, or no treatment Two studies comparing surgical or radiological treatment versus no treatment reported on live birth with differing directions of effect. As a result, we are uncertain whether surgical or radiological treatment improves live birth rates when compared to no treatment (risk ratio (RR) 2.27, 95% confidence interval (CI) 0.19 to 26.93; 2 RCTs, N = 204; I2 = 74%, very low-certainty evidence). Treatment may improve pregnancy rates compared to delayed or no treatment (RR 1.55, 95% CI 1.06 to 2.26; 13 RCTs, N = 1193; I2 = 65%, low-certainty evidence). This suggests that couples with no or delayed treatment have a 21% chance of pregnancy, whilst the pregnancy rate after surgical or radiological treatment is between 22% and 48%. We identified no evidence on adverse events, varicocele recurrence, or quality of life for this comparison. Surgical versus radiological treatment We are uncertain about the effect of surgical versus radiological treatment on live birth and on the following adverse events: hydrocele formation, pain, epididymitis, haematoma, and suture granuloma. We are uncertain about the effect of surgical versus radiological treatment on pregnancy rate (RR 1.13, 95% CI 0.75 to 1.70; 5 RCTs, N = 456, low-certainty evidence) and varicocele recurrence (RR 1.31, 95% CI 0.82 to 2.08; 3 RCTs, N = 380, low-certainty evidence). We identified no evidence on quality of life for this comparison. Surgery versus other surgical treatment We identified 19 studies comparing microscopic subinguinal surgical treatment to any other surgical treatment. Microscopic subinguinal surgical treatment probably improves pregnancy rates slightly compared to other surgical treatments (RR 1.18, 95% CI 1.02 to 1.36; 12 RCTs, N = 1473, moderate-certainty evidence). This suggests that couples with microscopic subinguinal surgical treatment have a 10% to 14% chance of pregnancy after treatment, whilst the pregnancy rate in couples after other surgical treatments is 10%. This procedure also probably reduces the risk of varicocele recurrence (RR 0.48, 95% CI 0.29, 0.79; 14 RCTs, N = 1565, moderate-certainty evidence). This suggests that 0.4% to 1.1% of men undergoing microscopic subinguinal surgical treatment experience recurrent varicocele, whilst 1.4% of men undergoing other surgical treatments do. Results for the following adverse events were inconclusive: hydrocele formation, haematoma, abdominal distension, testicular atrophy, wound infection, scrotal pain, and oedema. We identified no evidence on live birth or quality of life for this comparison. Nine studies compared open inguinal surgical treatment to retroperitoneal surgical treatment. Due to small sample sizes and methodological limitations, we identified neither treatment type as superior or inferior to the other regarding adverse events, pregnancy rates, or varicocele recurrence. We identified no evidence on live birth or quality of life for this comparison. Radiological versus other radiological treatment One study compared two types of radiological treatment (sclerotherapy versus embolisation) and reported 13% varicocele recurrence in both groups. Due to the broad confidence interval, no valid conclusion could be drawn (RR 1.00, 95% CI 0.16 to 6.20; 1 RCT, N = 30, very low-certainty evidence). We identified no evidence on live birth, adverse events, pregnancy, or quality of life for this comparison. AUTHORS' CONCLUSIONS: Based on the limited evidence, it remains uncertain whether any treatment (surgical or radiological) compared to no treatment in subfertile men may be of benefit on live birth rates; however, treatment may improve the chances for pregnancy. The evidence was also insufficient to determine whether surgical treatment was superior to radiological treatment. However, microscopic subinguinal surgical treatment probably improves pregnancy rates and reduces the risk of varicocele recurrence compared to other surgical treatments. High-quality, head-to-head comparative RCTs focusing on live birth rate and also assessing adverse events and quality of life are warranted.

Association between dietary satisfaction and depression, anxiety and stress in obese and overweight patients during the coronavirus pandemic.

BACKGROUND & AIM: The coronavirus disease-2019 (COVID-19) pandemic is a global health threat. The aim of this study was to evaluate the association between D-Sat and depression, anxiety and stress in obese patients during the coronavirus pandemic. METHODS: A cross-sectional study in 228 obese and overweight women on a weight loss diet was conducted through the use of two questionnaires. General characteristics, anthropometric indices, D-Sat and mental status were assessed in these patients. RESULTS: The greatest weight loss (WL) and waist circumference (WC) change was associated with the highest tertile of the D-Sat score in the first four months of the coronavirus pandemic (P < 0.05). Participants with the highest tertile of all D-sat score compared to those with the lowest had an 84% decrease in odds of depression. The highest tertile was also associated with decreased odds of anxiety (OR: 0.32 95%CI: 0.14; 0.68) The adjusted odds of stress score were negatively associated to the highest tertile of the D-Sat score (OR: 0.09, 95%CI (0.03, 0.23). WL was inversely related to stress (P < 0.05). Participants with higher WL and WC reduction had fewer depressive symptoms (P < 0.05). Sleep time and family income were associated with obesity. CONCLUSIONS: D-Sat and positive personal and family dynamics can improve the mental status of obese and overweight patients during quarantine.

Quarantine alone or in combination with other public health measures to control COVID-19: a rapid review.

BACKGROUND: Coronavirus disease 2019 (COVID-19) is a rapidly emerging disease classified as a pandemic by the World Health Organization (WHO). To support the WHO with their recommendations on quarantine, we conducted a rapid review on the effectiveness of quarantine during severe coronavirus outbreaks. OBJECTIVES: To assess the effects of quarantine (alone or in combination with other measures) of individuals who had contact with confirmed or suspected cases of COVID-19, who travelled from countries with a declared outbreak, or who live in regions with high disease transmission. SEARCH METHODS: An information specialist searched the Cochrane COVID-19 Study Register, and updated the search in PubMed, Ovid MEDLINE, WHO Global Index Medicus, Embase, and CINAHL on 23 June 2020. SELECTION CRITERIA: Cohort studies, case-control studies, time series, interrupted time series, case series, and mathematical modelling studies that assessed the effect of any type of quarantine to control COVID-19. We also included studies on SARS (severe acute respiratory syndrome) and MERS (Middle East respiratory syndrome) as indirect evidence for the current coronavirus outbreak. DATA COLLECTION AND ANALYSIS: Two review authors independently screened abstracts and titles in duplicate. Two review authors then independently screened all potentially relevant full-text publications. One review author extracted data, assessed the risk of bias and assessed the certainty of evidence with GRADE and a second review author checked the assessment. We used three different tools to assess risk of bias, depending on the study design: ROBINS-I for non-randomised studies of interventions, a tool provided by Cochrane Childhood Cancer for non-randomised, non-controlled studies, and recommendations from the International Society for Pharmacoeconomics and Outcomes Research (ISPOR) for modelling studies. We rated the certainty of evidence for the four primary outcomes: incidence, onward transmission, mortality, and costs. MAIN RESULTS: We included 51 studies; 4 observational studies and 28 modelling studies on COVID-19, one observational and one modelling study on MERS, three observational and 11 modelling studies on SARS, and three modelling studies on SARS and other infectious diseases. Because of the diverse methods of measurement and analysis across the outcomes of interest, we could not conduct a meta-analysis and undertook a narrative synthesis. We judged risk of bias to be moderate for 2/3 non-randomized studies of interventions (NRSIs) and serious for 1/3 NRSI. We rated risk of bias moderate for 4/5 non-controlled cohort studies, and serious for 1/5. We rated modelling studies as having no concerns for 13 studies, moderate concerns for 17 studies and major concerns for 13 studies. Quarantine for individuals who were in contact with a confirmed/suspected COVID-19 case in comparison to no quarantine Modelling studies consistently reported a benefit of the simulated quarantine measures, for example, quarantine of people exposed to confirmed or suspected cases may have averted 44% to 96% of incident cases and 31% to 76% of deaths compared to no measures based on different scenarios (incident cases: 6 modelling studies on COVID-19, 1 on SARS; mortality: 2 modelling studies on COVID-19, 1 on SARS, low-certainty evidence). Studies also indicated that there may be a reduction in the basic reproduction number ranging from 37% to 88% due to the implementation of quarantine (5 modelling studies on COVID-19, low-certainty evidence). Very low-certainty evidence suggests that the earlier quarantine measures are implemented, the greater the cost savings may be (2 modelling studies on SARS). Quarantine in combination with other measures to contain COVID-19 in comparison to other measures without quarantine or no measures When the models combined quarantine with other prevention and control measures, such as school closures, travel restrictions and social distancing, the models demonstrated that there may be a larger effect on the reduction of new cases, transmissions and deaths than measures without quarantine or no interventions (incident cases: 9 modelling studies on COVID-19; onward transmission: 5 modelling studies on COVID-19; mortality: 5 modelling studies on COVID-19, low-certainty evidence). Studies on SARS and MERS were consistent with findings from the studies on COVID-19. Quarantine for individuals travelling from a country with a declared COVID-19 outbreak compared to no quarantine Very low-certainty evidence indicated that the effect of quarantine of travellers from a country with a declared outbreak on reducing incidence and deaths may be small for SARS, but might be larger for COVID-19 (2 observational studies on COVID-19 and 2 observational studies on SARS). AUTHORS' CONCLUSIONS: The current evidence is limited because most studies on COVID-19 are mathematical modelling studies that make different assumptions on important model parameters. Findings consistently indicate that quarantine is important in reducing incidence and mortality during the COVID-19 pandemic, although there is uncertainty over the magnitude of the effect. Early implementation of quarantine and combining quarantine with other public health measures is important to ensure effectiveness. In order to maintain the best possible balance of measures, decision makers must constantly monitor the outbreak and the impact of the measures implemented. This review was originally commissioned by the WHO and supported by Danube-University-Krems. The update was self-initiated by the review authors.

Universal screening for SARS-CoV-2 infection: a rapid review.

BACKGROUND: Coronavirus disease 2019 (COVID-19) is caused by the novel betacoronavirus, severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Most people infected with SARS-CoV-2 have mild disease with unspecific symptoms, but about 5% become critically ill with respiratory failure, septic shock and multiple organ failure. An unknown proportion of infected individuals never experience COVID-19 symptoms although they are infectious, that is, they remain asymptomatic. Those who develop the disease, go through a presymptomatic period during which they are infectious. Universal screening for SARS-CoV-2 infections to detect individuals who are infected before they present clinically, could therefore be an important measure to contain the spread of the disease. OBJECTIVES: We conducted a rapid review to assess (1) the effectiveness of universal screening for SARS-CoV-2 infection compared with no screening and (2) the accuracy of universal screening in people who have not presented to clinical care for symptoms of COVID-19. SEARCH METHODS: An information specialist searched Ovid MEDLINE and the Centers for Disease Control (CDC) COVID-19 Research Articles Downloadable Database up to 26 May 2020. We searched Embase.com, the CENTRAL, and the Cochrane Covid-19 Study Register on 14 April 2020. We searched LitCovid to 4 April 2020. The World Health Organization (WHO) provided records from daily searches in Chinese databases and in PubMed up to 15 April 2020. We also searched three model repositories (Covid-Analytics, Models of Infectious Disease Agent Study [MIDAS], and Society for Medical Decision Making) on 8 April 2020. SELECTION CRITERIA: Trials, observational studies, or mathematical modelling studies assessing screening effectiveness or screening accuracy among general populations in which the prevalence of SARS-CoV2 is unknown. DATA COLLECTION AND ANALYSIS: After pilot testing review forms, one review author screened titles and abstracts. Two review authors independently screened the full text of studies and resolved any disagreements by discussion with a third review author. Abstracts excluded by a first review author were dually reviewed by a second review author prior to exclusion. One review author independently extracted data, which was checked by a second review author for completeness and accuracy. Two review authors independently rated the quality of included studies using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool for diagnostic accuracy studies and a modified form designed originally for economic evaluations for modelling studies. We resolved differences by consensus. We synthesized the evidence in narrative and tabular formats. We rated the certainty of evidence for days to outbreak, transmission, cases missed and detected, diagnostic accuracy (i.e. true positives, false positives, true negatives, false negatives) using the GRADE approach. MAIN RESULTS: We included 22 publications. Two modelling studies reported on effectiveness of universal screening. Twenty studies (17 cohort studies and 3 modelling studies) reported on screening test accuracy. Effectiveness of screening We included two modelling studies. One study suggests that symptom screening at travel hubs, such as airports, may slightly slow but not stop the importation of infected cases (assuming 10 or 100 infected travellers per week reduced the delay in a local outbreak to 8 days or 1 day, respectively). We assessed risk of bias as minor or no concerns, and certainty of evidence was low, downgraded for very serious indirectness. The second modelling study provides very low-certainty evidence that screening of healthcare workers in emergency departments using laboratory tests may reduce transmission to patients and other healthcare workers (assuming a transmission constant of 1.2 new infections per 10,000 people, weekly screening reduced infections by 5.1% within 30 days). The certainty of evidence was very low, downgraded for high risk of bias (major concerns) and indirectness. No modelling studies reported on harms of screening. Screening test accuracy All 17 cohort studies compared an index screening strategy to a reference reverse transcriptase polymerase chain reaction (RT-PCR) test. All but one study reported on the accuracy of single point-in-time screening and varied widely in prevalence of SARS-CoV-2, settings, and methods of measurement. We assessed the overall risk of bias as unclear in 16 out of 17 studies, mainly due to limited information on the index test and reference standard. We rated one study as being at high risk of bias due to the inclusion of two separate populations with likely different prevalences. For several screening strategies, the estimates of sensitivity came from small samples. For single point-in-time strategies, for symptom assessment, the sensitivity from 12 cohorts (524 people) ranged from 0.00 to 0.60 (very low-certainty evidence) and the specificity from 12 cohorts (16,165 people) ranged from 0.66 to 1.00 (low-certainty evidence). For screening using direct temperature measurement (3 cohorts, 822 people), international travel history (2 cohorts, 13,080 people), or exposure to known infected people (3 cohorts, 13,205 people) or suspected infected people (2 cohorts, 954 people), sensitivity ranged from 0.00 to 0.23 (very low- to low-certainty evidence) and specificity ranged from 0.90 to 1.00 (low- to moderate-certainty evidence). For symptom assessment plus direct temperature measurement (2 cohorts, 779 people), sensitivity ranged from 0.12 to 0.69 (very low-certainty evidence) and specificity from 0.90 to 1.00 (low-certainty evidence). For rapid PCR test (1 cohort, 21 people), sensitivity was 0.80 (95% confidence interval (CI) 0.44 to 0.96; very low-certainty evidence) and specificity was 0.73 (95% CI 0.39 to 0.94; very low-certainty evidence). One cohort (76 people) reported on repeated screening with symptom assessment and demonstrates a sensitivity of 0.44 (95% CI 0.29 to 0.59; very low-certainty evidence) and specificity of 0.62 (95% CI 0.42 to 0.79; low-certainty evidence). Three modelling studies evaluated the accuracy of screening at airports. The main outcomes measured were cases missed or detected by entry or exit screening, or both, at airports. One study suggests very low sensitivity at 0.30 (95% CI 0.1 to 0.53), missing 70% of infected travellers. Another study described an unrealistic scenario to achieve a 90% detection rate, requiring 0% asymptomatic infections. The final study provides very uncertain evidence due to low methodological quality. AUTHORS' CONCLUSIONS: The evidence base for the effectiveness of screening comes from two mathematical modelling studies and is limited by their assumptions. Low-certainty evidence suggests that screening at travel hubs may slightly slow the importation of infected cases. This review highlights the uncertainty and variation in accuracy of screening strategies. A high proportion of infected individuals may be missed and go on to infect others, and some healthy individuals may be falsely identified as positive, requiring confirmatory testing and potentially leading to the unnecessary isolation of these individuals. Further studies need to evaluate the utility of rapid laboratory tests, combined screening, and repeated screening. More research is also needed on reference standards with greater accuracy than RT-PCR. Given the poor sensitivity of existing approaches, our findings point to the need for greater emphasis on other ways that may prevent transmission such as face coverings, physical distancing, quarantine, and adequate personal protective equipment for frontline workers.