Atypical symptoms, SARS-CoV-2 test results and immunisation rates in 456 residents from eight nursing homes facing a COVID-19 outbreak

Attributable risk factors and trends in global burden of falls from 1990 to 2021: A comprehensive analysis based on Global Burden Of Disease Study 2021

BACKGROUND

Falls are a leading cause of disability-adjusted life years (DALYs) and mobility difficulties. Previous estimates have relied on restricted regional scope and lack a thorough global study. This study, for the first time, examines the evolving trends in the global burden of falls from 1990 to 2021, focusing on geographic variation in disease burden and risk factors, predicting the development of burden of falls. Our aim was to provide information for allocating medical resources, taking health policies into action, and making patient management systems operate better.

METHOD

Data on incident cases, deaths, and DALYs were collected for countries, regions, ages, and sexes worldwide from the Global Burden Disease (GBD) 2021 database. Using R (version 4.3.2), we calculated estimated annual percent changes (EAPCs) for assessing trends in age-standardized rates, visualized risk factors, and predicted the global burden of falls. Joinpoint regression (version 4.9.1.0) was used to identify significant temporal trends and change points.

RESULTS

In 2021, 548.8 million people were affected by falls. There were 215 million incidence, 43.8 million DALYs, and 800,000 deaths caused by falls. The incidence rate of falls increases with age, and sex inequalities exist. Compared with 1990, the age-standardized incidence rate (ASIR), death rate (ASDR), and DALY rate (ASDALYsR) declined despite an increase in absolute numbers. The ASDR and ASDALYsR of falls are expected to decline in the future, whereas the ASIR is expected to rise. The fall burden varied significantly according to region and its sociodemographic index (SDI). Both ASIR (R = 0.510, p < 0.001) and ASDALYsR (R = 0.2762, p < 0.001) were positively correlated with SDI. In contrast, ASDR (R=-0.536, p < 0.001) showed a consistently negative association with SDI. Low bone mineral density, occupational injuries, alcohol use, and smoking emerged as the top factors associated with fall-related DALYs and deaths.

CONCLUSIONS

The overall burden of falls declined between 1990 and 2021, but the future incidence is expected to increase. The global burden of falls remains unchanged and shows significant regional and sex-based differences. Effective prevention and strategies against risk factors are imperative for reducing the future burden.

Association between a geriatric measure tool and adverse outcomes among older adults treated in an emergency department: a retrospective cohort study

The COVID-19 pandemic provided an ideal scenario for studying the care of the elderly population, we implemented a tool named the Geriatric Measure (GM) tool to determine the severity and need for hospitalization. The objective of the study is to evaluate if the results of a brief Geriatric Measure tool are associated with mortality and other outcomes among older adults with COVID-19 treated in the emergency department. Retrospective observational cohort study. Participants were older adults (65 years and over) who required hospitalization for SARS CoV2 pneumonia. Patients were evaluated with the GM tool and were followed-up until death or discharge and associations between GM tool scores and mortality and other outcomes were assessed. A total of 275 patients were included. The proportion of patients who died increased with every category of the GM tool. Patients in category 1 (fit with good functional status) had a mortality of 24.7% versus those in category 4 (frail with poor functional status) who had a mortality of 51%. Our results show an association between our GM tool and mortality among older adults with pneumonia caused by SARS CoV2 and treated in the emergency department, and highlight the need of individualizing care for older patients.

Atypical Presentation of COVID-19 in Older Adults: A Scoping Review

Background

COVID-19 has currently well-described signs and symptoms. However, older adults often present with an atypical condition, which can confuse and delay diagnosis and treatment.

Summary

A scoping review was performed according to Joanna Briggs Institute methodology and prepared using the PRISMA-ScR. It included 61 studies. The objectives were to identify the atypical symptoms of COVID-19 in older adults and summarize and synthesize the evidence regarding the clinical outcomes of older adults with atypical presentations of COVID-19. Fifty-eight atypical symptoms were identified. Geriatric syndromes were the most prevalent atypical presentations of COVID-19. The prevalence of older adults with atypical presentation was 29 ± 18.45%. The mortality rate of older adults with atypical presentation was 28.3 ± 10.26 (17-37%).

Key Messages

This scoping review showed that geriatric syndromes represent a frequent atypical presentation of COVID-19 in older adults. It is necessary to give visibility to those presentations in older populations with COVID-19 to advance the required interventions.

Assessment of immunoglobin G (spike and nucleocapsid protein) response to COVID-19 vaccination in Palestine

INTRODUCTION

Many countries have begun immunization programs and established protocols to combat pandemics caused by the SARS-CoV-2 virus. Six months after vaccination, the antibody titers produced by the immunization begin to decline, and individuals whose first immunization (either one or two doses) did not provide adequate protection may require a booster dose.

METHODS

A quantitative cross-sectional survey of 18-year-olds and older was undertaken in the West Bank from June 15 to June 27, 2022. Each participant had 5 mL of blood drawn to be tested for IgG-S, IgG-N, and blood group.

RESULTS

All participants had positive IgG-S results; IgG-S values ranged between 77 and 40,000 AU/ml, with a mean value of 1254 AU/ml. The value of IgG-N ranged from 0 to 139.3 U/ml for all participants, with a mean value of 22.4 U/ml. 64 (37.2%) of the participants demonstrated positive IgG-N screening results, with mean values of 51.2 U/ml. Female participants' mean IgG concentration was higher than male participants. Furthermore, the results revealed that smokers had lower levels of vaccine-induced antibodies than nonsmokers. High significance was found in the time from the last vaccine till the blood sample test (T = 3.848, P < .001), and the group between 6 and 9 months was found to have higher mean values than the 9-months group (M = 15952).

CONCLUSIONS

Participants vaccinated with a higher number of vaccines tend to have higher IgG-S. To elevate total antibodies, booster doses are essential. Additional researchers are needed to examine the positive correlation between IgG-S and IgG-N.

Atypical presentation of COVID-19 in older patients is associated with frailty but not with adverse outcomes

PURPOSE

Older patients with COVID-19 can present with atypical complaints, such as falls or delirium. In other diseases, such an atypical presentation is associated with worse clinical outcomes. However, it is not known whether this extends to COVID-19. We aimed to study the association between atypical presentation of COVID-19, frailty and adverse outcomes, as well as the incidence of atypical presentation.

METHODS

We conducted a retrospective observational multi-center cohort study in eight hospitals in the Netherlands. We included patients aged ≥ 70 years hospitalized with COVID-19 between February 2020 until May 2020. Atypical presentation of COVID-19 was defined as presentation without fever, cough and/or dyspnea. We collected data concerning symptoms on admission, demographics and frailty parameters [e.g., Charlson Comorbidity Index (CCI) and Clinical Frailty Scale (CFS)]. Outcome data included Intensive Care Unit (ICU) admission, discharge destination and 30-day mortality.

RESULTS

We included 780 patients, 9.5% (n = 74) of those patients had an atypical presentation. Patients with an atypical presentation were older (80 years, IQR 76-86 years; versus 79 years, IQR 74-84, p = 0.044) and were more often classified as severely frail (CFS 6-9) compared to patients with a typical presentation (47.6% vs 28.7%, p = 0.004). Overall, there was no significant difference in 30-day mortality between the two groups in univariate analysis (32.4% vs 41.5%; p = 0.173) or in multivariate analysis [OR 0.59 (95% CI 0.34-1.0); p = 0.058].

CONCLUSIONS

In this study, patients with an atypical presentation of COVID-19 were more frail compared to patients with a typical presentation. Contrary to our expectations, an atypical presentation was not associated with worse outcomes.

Impact of the COVID-19 pandemic and corresponding control measures on long-term care facilities: a systematic review and meta-analysis

BACKGROUND

Long-term care facilities (LTCFs) were high-risk settings for COVID-19 outbreaks.

OBJECTIVE

To assess the impacts of the COVID-19 pandemic on LTCFs, including rates of infection, hospitalisation, case fatality, and mortality, and to determine the association between control measures and SARS-CoV-2 infection rates in residents and staff.

METHOD

We conducted a systematic search of six databases for articles published between December 2019 and 5 November 2021, and performed meta-analyses and subgroup analyses to identify the impact of COVID-19 on LTCFs and the association between control measures and infection rate.

RESULTS

We included 108 studies from 19 countries. These studies included 1,902,044 residents and 255,498 staff from 81,572 LTCFs, among whom 296,024 residents and 36,807 staff were confirmed SARS-CoV-2 positive. The pooled infection rate was 32.63% (95%CI: 30.29 ~ 34.96%) for residents, whereas it was 10.33% (95%CI: 9.46 ~ 11.21%) for staff. In LTCFs that cancelled visits, new patient admissions, communal dining and group activities, and vaccinations, infection rates in residents and staff were lower than the global rate. We reported the residents' hospitalisation rate to be 29.09% (95%CI: 25.73 ~ 32.46%), with a case-fatality rate of 22.71% (95%CI: 21.31 ~ 24.11%) and mortality rate of 15.81% (95%CI: 14.32 ~ 17.30%). Significant publication biases were observed in the residents' case-fatality rate and the staff infection rate, but not in the infection, hospitalisation, or mortality rate of residents.

CONCLUSION

SARS-CoV-2 infection rates would be very high among LTCF residents and staff without appropriate control measures. Cancelling visits, communal dining and group activities, restricting new admissions, and increasing vaccination would significantly reduce the infection rates.

Symptomatic and Asymptomatic SARS-CoV-2 Infection and Follow-up of Neutralizing Antibody Levels

OBJECTIVE

To investigate neutralizing antibody levels in symptomatic and asymptomatic patients with coronavirus disease 2019 (COVID-19) at 6 and 10 months after disease onset.

METHODS

Blood samples were collected at three different time points from 27 asymptomatic individuals and 69 symptomatic patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Virus-neutralizing antibody titers against SARS-CoV-2 in both groups were measured and statistically analyzed.

RESULTS

The symptomatic and asymptomatic groups had higher neutralizing antibodies at 3 months and 1-2 months post polymerase chain reaction confirmation, respectively. However, neutralizing antibodies in both groups dropped significantly to lower levels at 6 months post-PCR confirmation.

CONCLUSION

Continued monitoring of symptomatic and asymptomatic individuals with COVID-19 is key to controlling the infection.

How to tackle the global challenge of falls?

Worldwide, falls and accompanying injuries are increasingly common, making their prevention and management a critical global challenge. The wealth of evidence to support interventions to prevent falls has recently (2022) been distilled in the first World Falls Guideline for Prevention and Management for Older Adults. The core of falls prevention includes (i) risk assessment and stratification; (ii) general recommendations on optimising physical function and mobility for all and (iii) offering a holistic, multidomain intervention to older adults at high risk of falls, in which the older adult's priorities, beliefs and resources are carefully considered. In recent decades, sustainable and adequately resourced falls prevention has proved challenging, although evidence suggests that suboptimal implementation of falls prevention is ineffective. Future research should focus on understanding the most successful approaches for implementation. To further optimise falls prevention, recent developments include technological innovation to identify and prevent falls, including exergaming. Further work is warranted to understand how to best incorporate the concepts of frailty and sarcopenia in falls prevention and management. This themed collection includes key articles in the field of falls prevention, covering several topics including risk factors, effective interventions, older adult's views, implementation issues and future perspectives.

Managing the Impact of COVID-19 in Nursing Homes and Long-Term Care Facilities: An Update

Older adults in nursing homes are at greatest risk of morbidity and mortality from SARS-CoV-2 infection. Nursing home residents constituted one-third to more than half of all deaths during the early waves of the COVID-19 pandemic. Following this, widespread adaptation of infection prevention and control measures and the supply and use of personal protective equipment resulted in a significant decrease in nursing home infections and deaths. For nursing homes, the most important determinant of experiencing a SARS-CoV-2 outbreak in the first instance appears to be community-transmission levels (particularly with variants of concern), although nursing home size and quality, for-profit status, and sociodemographic characteristics are also important. Use of visitation bans, imposed to reduce the impact of COVID-19 on residents, must be delicately balanced against their impact on resident, friend or family, and staff well-being. The successful rollout of primary vaccination has resulted in a sharp decrease in morbidity and mortality from SARS-CoV-2 in nursing homes. However, emerging evidence suggests that vaccine efficacy may wane over time, and the use of a third or additional vaccine "booster" doses in nursing home residents restores protection afforded by primary vaccination. Ongoing monitoring of vaccine efficacy in terms of infection, morbidity, and mortality is crucial in this vulnerable group in informing ongoing SARS-CoV-2 vaccine boosting strategies. Here, we detail the impact of SARS-CoV-2 on nursing home residents and discuss important considerations in the management of nursing home SARS-CoV-2 outbreaks. We additionally examine the use of testing strategies, nonpharmacologic outbreak control measures and vaccination strategies in this cohort. Finally, the impact of SARS-CoV-2 on the sector is reflected on as we emphasize the need for adoption of universal standards of medical care and integration with wider public health infrastructure in nursing homes in order to provide a safe and effective long-term care sector.

Antibody response after first and second BNT162b2 vaccination to predict the need for subsequent injections in nursing home residents

We explored antibody response after first and second BNT162b2 vaccinations, to predict the need for subsequent injections in nursing home (NH) residents. 369 NH residents were tested for IgG against SARS-CoV-2 Receptor-Binding Domain (RBD-IgG) and nucleoprotein-IgG (SARS-CoV-2 IgG II Quant and SARS-CoV-2 IgG Alinity assays, Abbott Diagnostics). In NH residents with prior SARS-CoV-2 infection, the first dose elicited high RBD-IgG levels (≥ 4160 AU/mL) in 99/129 cases (76.9%), with no additional antibody gain after the second dose in 74 cases (74.7%). However, a low RBD-IgG level (< 1050 AU/mL) was observed in 28 (21.7%) residents. The persistence of nucleoprotein-IgG and a longer interval between infection and the first dose were associated with a higher RBD-IgG response (p < 0.0001 and p = 0.0013, respectively). RBD-IgG below 50 AU/mL after the first dose predicted failure to reach the antibody concentration associated with a neutralizing effect after the second dose (≥ 1050 AU/mL). The BNT162b2 vaccine elicited a strong humoral response after the first dose in a majority of NH residents with prior SARS-CoV-2 infection. However, about one quarter of these residents require a second injection. Consideration should be given to immunological monitoring in NH residents to optimize the vaccine response in this vulnerable population.

Occurrence and transmission potential of asymptomatic and presymptomatic SARS-CoV-2 infections: Update of a living systematic review and meta-analysis

BACKGROUND

Debate about the level of asymptomatic Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection continues. The amount of evidence is increasing and study designs have changed over time. We updated a living systematic review to address 3 questions: (1) Among people who become infected with SARS-CoV-2, what proportion does not experience symptoms at all during their infection? (2) What is the infectiousness of asymptomatic and presymptomatic, compared with symptomatic, SARS-CoV-2 infection? (3) What proportion of SARS-CoV-2 transmission in a population is accounted for by people who are asymptomatic or presymptomatic?

METHODS AND FINDINGS

The protocol was first published on 1 April 2020 and last updated on 18 June 2021. We searched PubMed, Embase, bioRxiv, and medRxiv, aggregated in a database of SARS-CoV-2 literature, most recently on 6 July 2021. Studies of people with PCR-diagnosed SARS-CoV-2, which documented symptom status at the beginning and end of follow-up, or mathematical modelling studies were included. Studies restricted to people already diagnosed, of single individuals or families, or without sufficient follow-up were excluded. One reviewer extracted data and a second verified the extraction, with disagreement resolved by discussion or a third reviewer. Risk of bias in empirical studies was assessed with a bespoke checklist and modelling studies with a published checklist. All data syntheses were done using random effects models. Review question (1): We included 130 studies. Heterogeneity was high so we did not estimate a mean proportion of asymptomatic infections overall (interquartile range (IQR) 14% to 50%, prediction interval 2% to 90%), or in 84 studies based on screening of defined populations (IQR 20% to 65%, prediction interval 4% to 94%). In 46 studies based on contact or outbreak investigations, the summary proportion asymptomatic was 19% (95% confidence interval (CI) 15% to 25%, prediction interval 2% to 70%). (2) The secondary attack rate in contacts of people with asymptomatic infection compared with symptomatic infection was 0.32 (95% CI 0.16 to 0.64, prediction interval 0.11 to 0.95, 8 studies). (3) In 13 modelling studies fit to data, the proportion of all SARS-CoV-2 transmission from presymptomatic individuals was higher than from asymptomatic individuals. Limitations of the evidence include high heterogeneity and high risks of selection and information bias in studies that were not designed to measure persistently asymptomatic infection, and limited information about variants of concern or in people who have been vaccinated.

CONCLUSIONS

Based on studies published up to July 2021, most SARS-CoV-2 infections were not persistently asymptomatic, and asymptomatic infections were less infectious than symptomatic infections. Summary estimates from meta-analysis may be misleading when variability between studies is extreme and prediction intervals should be presented. Future studies should determine the asymptomatic proportion of SARS-CoV-2 infections caused by variants of concern and in people with immunity following vaccination or previous infection. Without prospective longitudinal studies with methods that minimise selection and measurement biases, further updates with the study types included in this living systematic review are unlikely to be able to provide a reliable summary estimate of the proportion of asymptomatic infections caused by SARS-CoV-2.

REVIEW PROTOCOL

Open Science Framework (https://osf.io/9ewys/).

Analysing different exposures identifies that wearing masks and establishing COVID-19 areas reduce secondary-attack risk in aged-care facilities

BACKGROUND

The COVID-19 epidemic has spread rapidly within aged-care facilities (ACFs), where the infection-fatality ratio is high. It is therefore urgent to evaluate the efficiency of infection prevention and control (IPC) measures in reducing SARS-CoV-2 transmission.

METHODS

We analysed the COVID-19 outbreaks that took place between March and May 2020 in 12 ACFs using reverse transcription-polymerase chain reaction (RT-PCR) and serological tests for SARS-CoV-2 infection. Using maximum-likelihood approaches and generalized linear mixed models, we analysed the proportion of infected residents in ACFs and identified covariates associated with the proportion of infected residents.

RESULTS

The secondary-attack risk was estimated at 4.1%, suggesting a high efficiency of the IPC measures implemented in the region. Mask wearing and the establishment of COVID-19 zones for infected residents were the two main covariates associated with lower secondary-attack risks.

CONCLUSIONS

Wearing masks and isolating potentially infected residents appear to be associated with a more limited spread of SARS-CoV-2 in ACFs.

Antibody response after one and two jabs of the BNT162b2 vaccine in nursing home residents: The CONsort-19 study

Background

The humoral immune response following COVID‐19 vaccination in nursing home residents is poorly known. A longitudinal study compared levels of IgG antibodies against the spike protein (S‐RBD IgG) (S‐RDB protein IgG) after one and two BNT162b2/Pfizer jabs in residents with and without prior COVID‐19.

Methods

In 22 French nursing homes, COVID‐19 was diagnosed with real‐time reverse‐transcriptase polymerase chain reaction (RT‐PCR) for SARS‐CoV‐2. Blood S‐RDB‐protein IgG and nucleocapsid (N) IgG protein (N‐protein IgG) were measured 21–24 days after the first jab (1,004 residents) and 6 weeks after the second (820 residents).

Results

In 735 residents without prior COVID‐19, 41.7% remained seronegative for S‐RDB‐protein IgG after the first jab vs. 2.1% of the 270 RT‐PCR‐positive residents (p < 0.001). After the second jab, 3% of the 586 residents without prior COVID‐19 remained seronegative. However, 26.5% had low S‐RDB‐protein IgG levels (50–1050 UA/ml) vs. 6.4% of the 222 residents with prior COVID‐19. Residents with an older infection (first wave), or with N‐protein IgG at the time of vaccination, had the highest S‐RDB‐protein IgG levels. Residents with a prior COVID‐19 infection had higher S‐RDB‐protein IgG levels after one jab than those without after two jabs.

Interpretation

A single vaccine jab is sufficient to reach a high humoral immune response in residents with prior COVID‐19. Most residents without prior COVID‐19 are seropositive for S‐RDB‐protein IgG after the second jab, but around 30% have low levels. Whether residents with no or low post‐vaccine S‐RDB protein IgG are at higher risk of symptomatic COVID‐19 requires further analysis.

Waning immunity six months after BioNTech/Pfizer COVID-19 vaccination among nursing home residents in Zagreb, Croatia

AIM

To assess the humoral immunity to COVID-19 in nursing home residents six months after vaccination.

METHODS

This seroepidemiological research enrolled 118 residents of one nursing home in Zagreb. All participants received two doses of BioNTech/Pfizer COVID-19 and had no previously detected SARS-CoV-2 infection. The samples were tested for the presence of neutralizing antibodies using a virus neutralization test. A SARS-CoV-2 strain isolated in Vero E6 cells from a Croatian COVID-19 patient was used as a stock virus. Neutralizing antibody titer was defined as the reciprocal of the highest serum dilution that showed at least 50% neutralization. Neutralizing antibody titer ≥8 was considered positive.

RESULTS

Sixty-four (54%) participants had a positive neutralizing antibody titer, 27 (23%) had a low positive titer (titer 8), and 27 (23%) had a negative titer. Women had a significantly higher median titer than men (16 [interquartile range, IQR 24] vs 8 [IQR 12], Mann-Whitney U=1033, P=0.003). Age was negatively but not significantly correlated with neutralizing antibody titer (Spearman's rho -0.132, P=0.155).

CONCLUSION

Almost half of the participants (46%) had a negative or low positive titer six months after having been fully vaccinated. This study suggests that humoral immunity among nursing home residents considerably wanes six months after BioNTech/Pfizer COVID-19 vaccination. Our results could contribute to the discussion about the need for a booster dose.

WAO-ARIA consensus on chronic cough - Part II: Phenotypes and mechanisms of abnormal cough presentation - Updates in COVID-19

BACKGROUND

Chronic cough can be triggered by respiratory and non-respiratory tract illnesses originating mainly from the upper and lower airways, and the GI tract (ie, reflux). Recent findings suggest it can also be a prominent feature in obstructive sleep apnea (OSA), laryngeal hyperresponsiveness, and COVID-19. The classification of chronic cough is constantly updated but lacks clear definition. Epidemiological data on the prevalence of chronic cough are informative but highly variable. The underlying mechanism of chronic cough is a neurogenic inflammation of the cough reflex which becomes hypersensitive, thus the term hypersensitive cough reflex (HCR). A current challenge is to decipher how various infectious and inflammatory airway diseases and esophageal reflux, among others, modulate HCR.

OBJECTIVES

The World Allergy Organization/Allergic Rhinitis and its Impact on Asthma (WAO/ARIA) Joint Committee on Chronic Cough reviewed the current literature on classification, epidemiology, presenting features, and mechanistic pathways of chronic cough in airway- and reflux-related cough phenotypes, OSA, and COVID-19. The interplay of cough reflex sensitivity with other pathogenic mechanisms inherent to airway and reflux-related inflammatory conditions was also analyzed.

OUTCOMES

Currently, it is difficult to clearly ascertain true prevalence rates in epidemiological studies of chronic cough phenotypes. This is likely due to lack of standardized objective measures needed for cough classification and frequent coexistence of multi-organ cough origins. Notwithstanding, we emphasize the important role of HCR as a mechanistic trigger in airway- and reflux-related cough phenotypes. Other concomitant mechanisms can also modulate HCR, including type2/Th1/Th2 inflammation, presence or absence of deep inspiration-bronchoprotective reflex (lower airways), tissue remodeling, and likely cough plasticity, among others.

Failing the frail: The need to broaden the COVID-19 case definition for geriatric patients

The older population has a high mortality with COVID-19 and this cohort often presents atypically with infection. This study compares presenting complaints and observations of older patients with COVID-19 against the established case definition to determine whether the case definition should be broadened to better identify SARS-CoV-2 infection in this age group.This retrospective observational study analysed the presenting complaints and observations of people aged 70 years and over who were admitted to a district general hospital with confirmed SARS-CoV-2 infection from March to May 2020.Out of 225 patients, only 11.5% presented with the trio of cough, fever and breathlessness; 30.2% did not present with any of these symptoms (p<0.001). The most frequent atypical complaints were delirium (25%), general malaise (20%) and falls (19%). Only 32.4% recorded a temperature ≥37.6°C on admission while 20.4% were hypothermic with a temperature <36.4°C (p=0.0003).A significant proportion of older patients with COVID-19 presented with non-specific symptoms and observations. The high proportion of falls and delirium emphasises the need for early geriatrician input, awareness of COVID-19 as a differential for confusion in older patients and to include falls in the case definition for COVID-19 in the older population.

Asymptomatic SARS-CoV-2 infection: A systematic review and meta-analysis

Quantification of asymptomatic infections is fundamental for effective public health responses to the COVID-19 pandemic. Discrepancies regarding the extent of asymptomaticity have arisen from inconsistent terminology as well as conflation of index and secondary cases which biases toward lower asymptomaticity. We searched PubMed, Embase, Web of Science, and World Health Organization Global Research Database on COVID-19 between January 1, 2020 and April 2, 2021 to identify studies that reported silent infections at the time of testing, whether presymptomatic or asymptomatic. Index cases were removed to minimize representational bias that would result in overestimation of symptomaticity. By analyzing over 350 studies, we estimate that the percentage of infections that never developed clinical symptoms, and thus were truly asymptomatic, was 35.1% (95% CI: 30.7 to 39.9%). At the time of testing, 42.8% (95% prediction interval: 5.2 to 91.1%) of cases exhibited no symptoms, a group comprising both asymptomatic and presymptomatic infections. Asymptomaticity was significantly lower among the elderly, at 19.7% (95% CI: 12.7 to 29.4%) compared with children at 46.7% (95% CI: 32.0 to 62.0%). We also found that cases with comorbidities had significantly lower asymptomaticity compared to cases with no underlying medical conditions. Without proactive policies to detect asymptomatic infections, such as rapid contact tracing, prolonged efforts for pandemic control may be needed even in the presence of vaccination.

Rapid Point-Of-Care Serology and Clinical History Assessment Increase Protection Provided by RT-PCR Screening: A Pilot Study Involving Three Nursing Homes in Brescia, a Hotspot of Lombardy

Background: COVID-19 outbursts have been registered worldwide within care homes with asymptomatic transmission combined with shortage/inaccuracy of diagnostic tests undermining the efforts at containment of the disease. Nursing facilities in Lombardy (Italy) were left with no, or limited, access to testing for 8 weeks after the outbreak of COVID-19.

Methods: This study includes 246 residents and 286 workers of three different nursing homes in Brescia-Lombardy. Clinical questionnaires and rapid serology tests were devised to integrate the data of the first available RT-PCR screening. Follow-up serology after 60-days was performed on 67 of 86 workers with positive serology or clinically suspicious.

Findings: Thirty-seven residents and 18 workers had previous positive RT-PCR. Thorough screening disclosed two additional RT-PCR-positive workers. Serology screening revealed antibodies in 59 residents and 48 workers, including 32/37 residents and all workers previously positive at RT-PCR. Follow up serology disclosed antibodies in two additional workers with recent symptoms at the time of screening. The professionals in close contact with residents had more infections (47/226–20.79% vs. 1/60–1.66%; p = 0.00013 Fisher exact-test). A suspicious clinical score was present in 44/64 residents and in 41/50 workers who tested positive with either method with totally asymptomatic disease more frequent among residents 28.1 vs. 10.0% (p = 0.019 Fisher exact-test).

Interpretation: Based on the available RT-PCR ± results at the time of symptoms/contacts, our integrated clinical and serological screening demonstrated sensitivity 89% and specificity 87%. This multimodal assessment proved extremely useful in understanding the viral spread in nursing homes, in defining its stage and in implementing protective measures. Rapid serology tests demonstrated efficient and particularly suited for older people less able to move/cooperate.