Prevalence of Asymptomatic SARS-CoV-2 Infection

Cost effectiveness and decision analysis for national airport screening options to reduce risk of COVID-19 introduction in Uganda, 2020

INTRODUCTION

Early during the COVID-19 outbreak, various approaches were utilized to prevent COVID-19 introductions from incoming airport travellers. However, the costs and effectiveness of airport-specific interventions have not been evaluated.

METHODS

We evaluated policy options for COVID-19-specific interventions at Entebbe International Airport for costs and impact on COVID-19 case counts, we took the government payer perspective. Policy options included; (1)no screening, testing, or mandatory quarantine for any incoming traveller; (2)mandatory symptom screening for all incoming travellers with RT-PCR testing only for the symptomatic and isolation of positives; and (3)mandatory 14-day quarantine and one-time testing for all, with 10-day isolation of persons testing positive. We calculated incremental cost-effectiveness ratios (ICERs) in US$ per additional case averted.

RESULTS

Expected costs per incoming traveller were $0 (Option 1), $19 (Option 2), and $766 (Option 3). ICERs per case averted were $257 for Option 2 (which averted 4,948 cases), and $10,139 for Option 3 (which averted 5,097 cases) compared with Option I. Two-week costs were $0 for Option 1, $1,271,431 Option 2, and $51,684,999 Option 3. The per-case ICER decreased with increase in prevalence. The cost-effectiveness of our interventions was modestly sensitive to the prevalence of COVID-19, diagnostic test sensitivity, and testing costs.

CONCLUSION

Screening all incoming travellers, testing symptomatic persons, and isolating positives (Option 2) was the most cost-effective option. A higher COVID-19 prevalence among incoming travellers increased cost-effectiveness of airport-specific interventions. This model could be used to evaluate prevention options at the airport for COVID-19 and other infectious diseases with similar requirements for control.

Silent battles: immune responses in asymptomatic SARS-CoV-2 infection

SARS-CoV-2 infections manifest with a broad spectrum of presentations, ranging from asymptomatic infections to severe pneumonia and fatal outcomes. This review centers on asymptomatic infections, a widely reported phenomenon that has substantially contributed to the rapid spread of the pandemic. In such asymptomatic infections, we focus on the role of innate, humoral, and cellular immunity. Notably, asymptomatic infections are characterized by an early and robust innate immune response, particularly a swift type 1 IFN reaction, alongside a rapid and broad induction of SARS-CoV-2-specific T cells. Often, antibody levels tend to be lower or undetectable after asymptomatic infections, suggesting that the rapid control of viral replication by innate and cellular responses might impede the full triggering of humoral immunity. Even if antibody levels are present in the early convalescent phase, they wane rapidly below serological detection limits, particularly following asymptomatic infection. Consequently, prevalence studies reliant solely on serological assays likely underestimate the extent of community exposure to the virus.

Quantifying the presymptomatic transmission of COVID-19 in the USA

The emergence of many presymptomatic hidden transmission events significantly complicated the intervention and control of the spread of COVID-19 in the USA during the year 2020. To analyze the role that presymptomatic infections play in the spread of this disease, we developed a state-level metapopulation model to simulate COVID-19 transmission in the USA in 2020 during which period the number of confirmed cases was more than in any other country. We estimated that the transmission rate (i.e., the number of new infections per unit time generated by an infected individual) of presymptomatic infections was approximately 59.9% the transmission rate of reported infections. We further estimated that {at any point in time the} average proportion of infected individuals in the presymptomatic stage was consistently over 50% of all infected individuals. Presymptomatic transmission was consistently contributing over 52% to daily new infections, as well as consistently contributing over 50% to the effective reproduction number from February to December. Finally, non-pharmaceutical intervention targeting presymptomatic infections was very effective in reducing the number of reported cases. These results reveal the significant contribution that presymptomatic transmission made to COVID-19 transmission in the USA during 2020, as well as pave the way for the design of effective disease control and mitigation strategies.

Death Anxiety Among Pakistani HCWs: The Role of COVID-19 Vaccine Acceptance and Positive Religious Coping Strategy

Background: The mental health of healthcare workers (HCWs) has been significantly impacted by the COVID-19 pandemic. To address this, spirituality and religious coping mechanisms have been suggested as a way to maintain well-being and reduce anxiety levels. Additionally, vaccination has been shown to play an essential role in lowering anxiety levels, including death anxiety. However, there is a lack of evidence on how positive religious coping strategies and COVID-19 immunization affect death anxiety levels. To fill this gap, this study uses a Pakistani HCWs sample. Methods: This study collected cross-sectional data from 389 HCWs on socio-demographics, positive religious coping strategies, vaccine acceptance, and death anxiety. Hypothesis testing was done using Statistical Package for the Social Sciences (SPSS) and Partial Least Squares (PLS) by adopting the Structural Equation Modeling (SEM) technique. Results: The results showed that the positive religious coping strategy and acceptance of the COVID-19 vaccine reduced death anxiety among HCWs in Pakistan. HCWs practicing the positive religious coping strategy and vaccine acceptance had lower levels of death anxiety symptoms. Thus, the positive religious coping strategy has a direct effect on reducing death anxiety. Conclusion: In conclusion, COVID-19 immunization positively affects individual mental health by reducing death anxiety. Vaccines protect individuals from COVID-19 infection, providing a sense of security that reduces the chance of death anxiety among HCWs attending to COVID-19 patients.

Curtailing virus-induced inflammation in respiratory infections: emerging strategies for therapeutic interventions

Acute respiratory viral infections (ARVI) are the most common illnesses worldwide. In some instances, mild cases of ARVI progress to hyperinflammatory responses, which are damaging to pulmonary tissue and requiring intensive care. Here we summarize available information on preclinical and clinical effects of XC221GI (1-[2-(1-methyl imidazole-4-yl)-ethyl]perhydroazin-2,6-dione), an oral drug with a favorable safety profile that has been tested in animal models of influenza, respiratory syncytial virus, highly pathogenic coronavirus strains and other acute viral upper respiratory infections. XC221GI is capable of controlling IFN-gamma-driven inflammation as it is evident from the suppression of the production of soluble cytokines and chemokines, including IL-6, IL-8, CXCL10, CXCL9 and CXCL11 as well as a decrease in migration of neutrophils into the pulmonary tissue. An excellent safety profile of XC221GI, which is not metabolized by the liver, and its significant anti-inflammatory effects indicate utility of this compound in abating conversion of ambulatory cases of respiratory infections into the cases with aggravated presentation that require hospitalization. This drug is especially useful when rapid molecular assays determining viral species are impractical, or when direct antiviral drugs are not available. Moreover, XC221GI may be combined with direct antiviral drugs to enhance their therapeutic effects.

Immunogenicity and protective efficacy of SARS-CoV-2 mRNA vaccine encoding secreted non-stabilized spike in female mice

Establishment of an mRNA vaccine platform in low- and middle-income countries (LMICs) is important to enhance vaccine accessibility and ensure future pandemic preparedness. Here, we describe the preclinical studies of "ChulaCov19", a SARS-CoV-2 mRNA encoding prefusion-unstabilized ectodomain spike protein encapsulated in lipid nanoparticles (LNP). In female BALB/c mice, ChulaCov19 at 0.2, 1, 10, and 30 μg elicits robust neutralizing antibody (NAb) and T cell responses in a dose-dependent relationship. The geometric mean titers (GMTs) of NAb against wild-type (WT, Wuhan-Hu1) virus are 1,280, 11,762, 54,047, and 62,084, respectively. Higher doses induce better cross-NAb against Delta (B.1.617.2) and Omicron (BA.1 and BA.4/5) variants. This elicited immunogenicity is significantly higher than those induced by homologous CoronaVac or AZD1222 vaccination. In a heterologous prime-boost study, ChulaCov19 booster dose generates a 7-fold increase of NAb against Wuhan-Hu1 WT virus and also significantly increases NAb response against Omicron (BA.1 and BA.4/5) when compared to homologous CoronaVac or AZD1222 vaccination. Challenge studies show that ChulaCov19 protects human-ACE-2-expressing female mice from COVID-19 symptoms, prevents viremia and significantly reduces tissue viral load. Moreover, anamnestic NAb response is undetectable in challenge animals. ChulaCov19 is therefore a promising mRNA vaccine candidate either as a primary or boost vaccination and has entered clinical development.

Front-Line vs Second-Line Healthcare Workers: Susceptibility Prediction to COVID-19 Infection in a Tertiary Care Teaching Institute

Background Since the beginning of the novel coronavirus disease in Wuhan city of China in 2019 and its spreading worldwide and taking the form of a pandemic, many healthcare workers (HCWs) were affected by coronavirus disease 2019 (COVID-19) infection. Though we have used many types of personal protective equipment (PPE) kits while taking care of COVID-19 patients, we have seen COVID-19 susceptibility in different working areas were different. The pattern of infection in different working areas depended on HCWs following COVID-19 appropriate behavior. Therefore, we planned to estimate the susceptibility of front-line HCWs and second-line HCWs to getting COVID-19 infection. Aim To determine the risk of COVID-19 in front-line healthcare workers as compared to second-line healthcare workers. Method and materials We planned a retrospective cross-sectional analysis of COVID-19-positive healthcare workers from our institute within six months. Their nature of duty was analyzed and they were divided into two groups: 1) Front-line HCWs were defined as those who were working or who have worked in screening areas of the outpatient department (OPD) or COVID-19 isolation wards within the prior 14 days and provided direct care to patients with confirmed or suspected COVID-19. 2) Second-line HCWs were those who were working in the general OPD or non-COVID-19 areas of our hospital and did not have contact with COVID-19-positive patients. Results A total of 59 HCWs became COVID-19 positive during the study period, 23 as front-line and 36 as second-line HCWs. The mean (SD) duration of work as a front-line worker was 51 and as a second-line worker was 84.4 hours. Fever, cough, body ache, loss of taste, loose stools, palpitation, throat pain, vertigo, vomiting, lung disease, generalized weakness, breathing difficulty, loss of smell, headache, and running nose were present in 21 (35.6%), 15 (25.4%), 9 (15.3%), 10 (16.9%), 3 (5.1%), 5 (8.5%), 5 (8.5%), 1 (1.7%), 4 (6.8%), 2 (3.4%), 11 (18.6%), 4 (6.8%), 9 (15.3%), 6 (10.2%) and 3 (5.1%), respectively. To predict the risk of getting COVID-19 infection in HCWs, binary logistic regression with COVID-19 diagnosis as the output variable was modeled with hours of working in COVID-19 wards as front-line and second-line workers as independent variables. The results showed that there was a 1.18 times increased risk of acquiring the disease for every one-hour excess of working as a front-line worker, whereas, for second-line workers, it was slightly lower, with a 1.11 times increased risk for developing COVID-19 disease with every one hour increase in duty hours. Both these associations were statistically significant (p=0.001 for front-line and 0.006 for second-line HCWs). Conclusion COVID-19 has taught us the importance of COVID-19 appropriate behavior in preventing the spread of respiratory organisms. Our study has shown that both the front-line and second-line HCWs are at increased risk of getting the infection and proper use of a PPE kit or mask can decrease the spread of such respiratory pathogens.

Asymptomatic SARS-CoV-2 Infection by Age: A Global Systematic Review and Meta-analysis

BACKGROUND

Asymptomatic SARS-CoV-2 infections have raised concerns for public health policies to manage epidemics. This systematic review and meta-analysis aimed to estimate the age-specific proportion of asymptomatic SARS-CoV-2 infected persons globally by year of age.

METHODS

We searched PubMed, Embase, medRxiv and Google Scholar on September 10, 2020, and March 1, 2021. We included studies conducted during January to December 2020, before routine vaccination against COVID-19. Because we expected the relationship between the asymptomatic proportion and age to be nonlinear, multilevel mixed-effects logistic regression (QR decomposition) with a restricted cubic spline was used to model asymptomatic proportions as a function of age.

RESULTS

A total of 38 studies were included in the meta-analysis. In total, 6556 of 14,850 cases were reported as asymptomatic. The overall estimate of the proportion of people who became infected with SARS-CoV-2 and remained asymptomatic throughout infection was 44.1% (6556/14,850, 95% CI: 43.3%-45.0%). The predicted asymptomatic proportion peaked in children (36.2%, 95% CI: 26.0%-46.5%) at 13.5 years, gradually decreased by age and was lowest at 90.5 years of age (8.1%, 95% CI: 3.4%-12.7%).

CONCLUSIONS

Given the high rates of asymptomatic carriage in adolescents and young adults and their active role in virus transmission in the community, heightened vigilance and public health strategies are needed among these individuals to prevent disease transmission.

The danger of the single storyline obfuscating the complexities of managing SARS-CoV-2/COVID-19

Chimamanda Ngozi Adichie showed how a single story is limited and thereby distorts the true nature of an issue. During this COVID-19 pandemic there have been, at least, three consecutive single stories-the 'lethal threat' story, followed by the 'economic threat' story, and finally the 'vaccine miracle' story. None of these single stories can convincingly and permanently capture the dynamics of the pandemic. This is because countries experienced different morbidity and mortality patterns, different socioeconomic disadvantage, age and vulnerability of population, timing and level of lockdown with economic variability, and, despite heavy promotion, vaccines were beset with a significant and variable degree of hesitancy. Lack of transparency, coherence and consistency of pandemic management-arising from holding on to single storylines-showed the global deficiency of public health policy and planning, an underfunding of (public) health and social services, and a growing distrust in governments' ability to manage crises effectively. Indeed, the global management has increased already large inequities, and little has been learnt to address the growing crises of more infectious and potentially more lethal virus mutations. Holding onto single stories prevents the necessary learnings to understand and manage the complexities of 'wicked' problems, whereas listening to the many stories provides insights and pathways to do so effectively as well as efficiently.

The Implementation and Role of Antigen Rapid Test for COVID-19 in Hemodialysis Units

As we move into the third year with COVID-19, many countries have attempted to manage the disease as an endemic. However, this is limited by the disease's morbidity and mortality, the emergence of new strains, and the effectiveness of the vaccine. This brief report describes, evaluates, and discusses the implementation of regular antigen rapid tests (ARTs) for COVID-19 in hemodialysis units. We introduced ARTs during the surge in our hemodialysis units. As compliance with the test was mandatory by regulatory requirements, we surveyed patients and caregivers to measure their acceptability, appropriateness, and feasibility of the ART's implementation. Acceptability measured confidence and level of comfort when performing ART tests, while appropriateness measured the perception of the necessity of ARTs, safety in the dialysis unit with the implementation of ARTs, and understanding using a Likert scale. Feasibility measured the perception of the timely start of dialysis treatment and the convenience of the test. Our survey found that ARTs were acceptable to 98% of patients and caregivers, with the majority reporting no discomfort. The majority of the patients agreed that ARTs were appropriate and feasible. We reported successful ART implementation in a healthcare setting with no false-positive or transmission within the unit during this period. Nevertheless, the long-term implementation outcome will require further evaluation.

SARS-CoV-2 Infection and the Risk of Suicidal and Self-Harm Thoughts and Behaviour: A Systematic Review

OBJECTIVE

The COVID-19 pandemic has had a complex impact on risks of suicide and non-fatal self-harm worldwide with some evidence of increased risk in specific populations including women, young people, and people from ethnic minority backgrounds. This review aims to systematically address whether SARS-CoV-2 infection and/or COVID-19 disease confer elevated risk directly.

METHOD

As part of a larger Living Systematic Review examining self-harm and suicide during the pandemic, automated daily searches using a broad list of keywords were performed on a comprehensive set of databases with data from relevant articles published between January 1, 2020 and July 18, 2021. Eligibility criteria for our present review included studies investigating suicide and/or self-harm in people infected with SARS-CoV-2 with or without manifestations of COVID-19 disease with a comparator group who did not have infection or disease. Suicidal and self-harm thoughts and behaviour (STBs) were outcomes of interest. Studies were excluded if they reported data for people who only had potential infection/disease without a confirmed exposure, clinical/molecular diagnosis or self-report of a positive SARS-CoV-2 test result. Studies of news reports, treatment studies, and ecological studies examining rates of both SARS-CoV-2 infections and suicide/self-harm rates across a region were also excluded.

RESULTS

We identified 12 studies examining STBs in nine distinct samples of people with SARS-CoV-2. These studies, which investigated STBs in the general population and in subpopulations, including healthcare workers, generally found positive associations between SARS-CoV-2 infection and/or COVID-19 disease and subsequent suicidal/self-harm thoughts and suicidal/self-harm behaviour.

CONCLUSIONS

This review identified some evidence that infection with SARS-CoV-2 and/or COVID-19 disease may be associated with increased risks for suicidal and self-harm thoughts and behaviours but a causal link cannot be inferred. Further research with longer follow-up periods is required to confirm these findings and to establish whether these associations are causal.

On the definition of dermatological disease. Part 1: conceptual frameworks

Little attention is paid to disease definition in dermatology and how such definitions come about, yet defining a disease is a fundamental step upon which all subsequent clinical management and prognostic judgements depend. Developing diagnostic criteria is also a critically important step for research purposes so that studies referring to groups of people can be compared in a meaningful way. This short review introduces the concepts of regressive and progressive nosology, and how definitions of a dermatological disease can evolve in a useful way as knowledge about that disease increases. It also highlights the dangers of panchrestons - names that try to explain all yet end up explaining very little. It also considers approaches to disease definition, such as whether a binary yes/no or continuous approach is more appropriate. Conceptual frameworks including essentialistic vs. nominalistic approaches using the biomedical or biopsychosocial perspectives are articulated. The review then illustrates hazards of underdiagnosis and overdiagnosis, and introduces the notion of 'disease mongering' - the selling of disease in order to promote the use of medicines. The review concludes with a reaffirmation of the importance of defining dermatological disease, and why any new diagnostic criteria must be shown to increase predictive ability before they are assimilated into clinical practice and research.

Durability of Protection Post-Primary COVID-19 Vaccination in the United States

The durability of immune responses after COVID-19 vaccination will drive long-term vaccine effectiveness across settings and may differ by vaccine type. To determine durability of protection of COVID-19 vaccines (BNT162b2, mRNA-1273, and Ad26.COV2.S) following primary vaccination in the United States, a matched case-control study was conducted in three cohorts between 1 January and 7 September 2021 using de-identified data from a database covering 168 million lives. Odds ratios (ORs) for developing outcomes of interest (breakthrough SARS-CoV-2 infection, hospitalization, or intensive care unit admission) were determined for each vaccine (no direct comparisons). In total, 17,017,435 individuals were identified. Relative to the baseline, stable protection was observed for Ad26.COV2.S against infections (OR [95% confidence interval (CI)], 1.31 [1.18–1.47]) and hospitalizations (OR [95% CI], 1.25 [0.86–1.80]). Relative to the baseline, protection waned over time against infections for BNT162b2 (OR [95% CI], 2.20 [2.01–2.40]) and mRNA-1273 (OR [95% CI], 2.07 [1.87–2.29]) and against hospitalizations for BNT162b2 (OR [95% CI], 2.38 [1.79–3.17]). Baseline protection remained stable for intensive care unit admissions for all three vaccines. Calculated baseline VE was consistent with published literature. This study suggests that the three vaccines in three separate populations may have different durability profiles.

Expansion of droplets during speaking and singing in Japanese

During the COVID-19 pandemic, a number of infection clusters associated with choral singing have been reported. Singing generates droplets and carries the risk of spreading infection. However, no reports have explored droplet flight and aerosol production rates by singing and speaking in Japanese. First, we conducted an observation experiment evaluating the maximum flight distance and number of droplets generated by singing in Japanese, using a high-speed camera and particle counter. Twenty amateur choir members, 10 male and 10 female (five members for each of the four voices), participated in the experiment. Subsequently, although the maximum distance that droplets traveled by singing in Japanese was 61 cm for men (median of 46.5, interquartile range, 36–57) and 56 cm for women (median of 27.5, interquartile range, 20–50), droplets were observed anteriorly and laterally to be up to 66.8 cm. At the singer’s mouth, ≥ 5 μm droplets were observed, whereas not observed at 1 meter toward the front of the singers in women and men, respectively. In German singing, droplets were observed up to 111 cm toward the front of the singer, possibly reflecting differences in pronunciation. In Japanese reading aloud, droplets were also observed up to 47 cm toward the front, whereas no droplet dispersion was observed by speaking the Japanese /a/ vowel or singing with wearing surgical mask toward the front. The aerosols produced when reading singing the /u/ vowels were significantly higher than those in other vowels. When singing in a choral group, keeping a sufficient distance at the front and side is recommended in minimizing infectious spread. If distance is not possible, practicing with /a/ vowels and avoiding consonants may be an alternative method. Our observations lasted only 50 seconds per song, and further observational studies are needed to determine the dynamics of aerosols that stay for long periods.

Pediatric SARS-CoV-2 Seroprevalence in Arkansas Over the First Year of the COVID-19 Pandemic

BACKGROUND

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) seroprevalence studies largely focus on adults, but little is known about spread in children. We determined SARS-CoV-2 seroprevalence in children and adolescents from Arkansas over the first year of the coronavirus disease of 2019 (COVID-19) pandemic.

METHODS

We tested remnant serum samples from children ages 1-18 years who visited Arkansas hospitals or clinics for non-COVID-19-related reasons from April 2020 through April 2021 for SARS-CoV-2 antibodies. We used univariable and multivariable regression models to determine the association between seropositivity and participant characteristics.

RESULTS

Among 2357 participants, seroprevalence rose from 7.9% in April/May 2020 (95% CI, 4.9-10.9) to 25.0% in April 2021 (95% CI, 21.5-28.5). Hispanic and black children had a higher association with antibody positivity than non-Hispanic and white children, respectively, in multiple sampling periods.

CONCLUSIONS

By spring 2021, most children in Arkansas were not infected with SARS-CoV-2. With the emergence of SARS-CoV-2 variants, recognition of long-term effects of COVID-19, and the lack of an authorized pediatric SARS-CoV-2 vaccine at the time, these results highlight the importance of including children in SARS-CoV-2 public health, clinical care, and research strategies.

A global systematic analysis of the occurrence, severity, and recovery pattern of long COVID in 2020 and 2021

Importance

While much of the attention on the COVID-19 pandemic was directed at the daily counts of cases and those with serious disease overwhelming health services, increasingly, reports have appeared of people who experience debilitating symptoms after the initial infection. This is popularly known as long COVID.

Objective

To estimate by country and territory of the number of patients affected by long COVID in 2020 and 2021, the severity of their symptoms and expected pattern of recovery.

Design

We jointly analyzed ten ongoing cohort studies in ten countries for the occurrence of three major symptom clusters of long COVID among representative COVID cases. The defining symptoms of the three clusters (fatigue, cognitive problems, and shortness of breath) are explicitly mentioned in the WHO clinical case definition. For incidence of long COVID, we adopted the minimum duration after infection of three months from the WHO case definition. We pooled data from the contributing studies, two large medical record databases in the United States, and findings from 44 published studies using a Bayesian meta-regression tool. We separately estimated occurrence and pattern of recovery in patients with milder acute infections and those hospitalized. We estimated the incidence and prevalence of long COVID globally and by country in 2020 and 2021 as well as the severity-weighted prevalence using disability weights from the Global Burden of Disease study.

Results

Analyses are based on detailed information for 1906 community infections and 10526 hospitalized patients from the ten collaborating cohorts, three of which included children. We added published data on 37262 community infections and 9540 hospitalized patients as well as ICD-coded medical record data concerning 1.3 million infections. Globally, in 2020 and 2021, 144.7 million (95% uncertainty interval [UI] 54.8-312.9) people suffered from any of the three symptom clusters of long COVID. This corresponds to 3.69% (1.38-7.96) of all infections. The fatigue, respiratory, and cognitive clusters occurred in 51.0% (16.9-92.4), 60.4% (18.9-89.1), and 35.4% (9.4-75.1) of long COVID cases, respectively. Those with milder acute COVID-19 cases had a quicker estimated recovery (median duration 3.99 months [IQR 3.84-4.20]) than those admitted for the acute infection (median duration 8.84 months [IQR 8.10-9.78]). At twelve months, 15.1% (10.3-21.1) continued to experience long COVID symptoms.

Conclusions and relevance

The occurrence of debilitating ongoing symptoms of COVID-19 is common. Knowing how many people are affected, and for how long, is important to plan for rehabilitative services and support to return to social activities, places of learning, and the workplace when symptoms start to wane.

Key Points

Question: What are the extent and nature of the most common long COVID symptoms by country in 2020 and 2021?Findings: Globally, 144.7 million people experienced one or more of three symptom clusters (fatigue; cognitive problems; and ongoing respiratory problems) of long COVID three months after infection, in 2020 and 2021. Most cases arose from milder infections. At 12 months after infection, 15.1% of these cases had not yet recovered.Meaning: The substantial number of people with long COVID are in need of rehabilitative care and support to transition back into the workplace or education when symptoms start to wane.

<em>In vitro</em> and <em>in vivo</em> pharmacodynamic activity of the new compound XC221GI in models of the viral inflammation of the respiratory tract

The viruses most commonly affecting the human respiratory tract include rhinoviruses, respiratory syncytial virus (RSV), influenza viruses, and coronaviruses (CoVs). The virus infection of the epithelial cells of the respiratory tract triggers an inflammation accompanied by the release of pro-inflammatory cytokines and chemokines including IL6, IL8(CXCL8), IL1β, and tumor necrosis factor α (TNFα). A subsequent acute inflammatory response in the lungs is accompanied by an increase in the production of cytokines and chemokines − CXCR3 receptor ligands – that are key players of acute inflammatory response that induce an influx of neutrophils and T cells into the lungs.

We studied the pharmacodynamic activity of the new compound XC221GI to suppress the IL6 and IL8 of an experimental RSV infection in vitro in human lung carcinoma cells A549 and in vivo in the lungs of cotton rats. We also studied the effect of XC221GI on the production of the chemokines CXCL10, CXCL9, and CXCL11 in mouse bronchoalveolar lavage as well as on the influx of neutrophils into the mouse lungs after the intranasal administration of interferon γ (IFNγ).

The obtained results demonstrate the anti-inflammatory activity of XC221GI, which suppresses the production of excessive levels of the key inflammatory markers IL6, IL8, CXCL10, CXCL9, and CXCL11 as well as the influx of neutrophils into the lungs thereby reducing lung pathology. These data confirm the effectiveness of XC221GI as a means of preventive anti-inflammatory therapy during a viral infection of the respiratory tract.

An exploration of the political, social, economic and cultural factors affecting how different global regions initially reacted to the COVID-19 pandemic

Responses to the early (February-July 2020) COVID-19 pandemic varied widely, globally. Reasons for this are multiple but likely relate to the healthcare and financial resources then available, and the degree of trust in, and economic support provided by, national governments. Cultural factors also affected how different populations reacted to the various pandemic restrictions, like masking, social distancing and self-isolation or self-quarantine. The degree of compliance with these measures depended on how much individuals valued their needs and liberties over those of their society. Thus, several themes may be relevant when comparing pandemic responses across different regions. East and Southeast Asian populations tended to be more collectivist and self-sacrificing, responding quickly to early signs of the pandemic and readily complied with most restrictions to control its spread. Australasian, Eastern European, Scandinavian, some Middle Eastern, African and South American countries also responded promptly by imposing restrictions of varying severity, due to concerns for their wider society, including for some, the fragility of their healthcare systems. Western European and North American countries, with well-resourced healthcare systems, initially reacted more slowly, partly in an effort to maintain their economies but also to delay imposing pandemic restrictions that limited the personal freedoms of their citizens.

Genetic Loci Associated With COVID-19 Positivity and Hospitalization in White, Black, and Hispanic Veterans of the VA Million Veteran Program

SARS-CoV-2 has caused symptomatic COVID-19 and widespread death across the globe. We sought to determine genetic variants contributing to COVID-19 susceptibility and hospitalization in a large biobank linked to a national United States health system. We identified 19,168 (3.7%) lab-confirmed COVID-19 cases among Million Veteran Program participants between March 1, 2020, and February 2, 2021, including 11,778 Whites, 4,893 Blacks, and 2,497 Hispanics. A multi-population genome-wide association study (GWAS) for COVID-19 outcomes identified four independent genetic variants (rs8176719, rs73062389, rs60870724, and rs73910904) contributing to COVID-19 positivity, including one novel locus found exclusively among Hispanics. We replicated eight of nine previously reported genetic associations at an alpha of 0.05 in at least one population-specific or the multi-population meta-analysis for one of the four MVP COVID-19 outcomes. We used rs8176719 and three additional variants to accurately infer ABO blood types. We found that A, AB, and B blood types were associated with testing positive for COVID-19 compared with O blood type with the highest risk for the A blood group. We did not observe any genome-wide significant associations for COVID-19 severity outcomes among those testing positive. Our study replicates prior GWAS findings associated with testing positive for COVID-19 among mostly White samples and extends findings at three loci to Black and Hispanic individuals. We also report a new locus among Hispanics requiring further investigation. These findings may aid in the identification of novel therapeutic agents to decrease the morbidity and mortality of COVID-19 across all major ancestral populations.

Anti-SARS-CoV-2 IgA Identifies Asymptomatic Infection in First Responders

Background

IgA is an important component of the early immune response to SARS-CoV-2. Prior serosurveys in high-risk groups employing IgG testing alone have provided discordant estimates. The potential added benefit of IgA in serosurveys has not been established.

Methods

Longitudinal serosurvey of first responders (police, emergency medical service providers, fire fighters, and other staff) employing three serologic tests: anti-spike IgA, anti-spike IgG, and anti-nucleocapsid IgG correlated with surveys assessing occupational and non-occupational risk, exposure to COVID-19 and illnesses consistent with COVID-19.

Results

Twelve percent of first responders in Colorado at baseline and 22% at follow-up were assessed as having SARS-CoV-2 infection. Five percent at baseline and 6% at follow-up were seropositive only for IgA. Among those IgA positive only at baseline, the majority 69% had a positive antibody at follow-up. 45% of those infected at baseline and 33% at follow-up were asymptomatic. At all time points, the estimated cumulative incidence in our study was higher than that in the general population.

Conclusions

First responders are at high risk of infection with SARS-CoV-2. IgA testing identified a significant portion of cases missed by IgG testing and its use as part of serologic surveys may improve retrospective identification of asymptomatic infection.

Prevalence, clinical characteristics and outcomes of Guillain-Barré syndrome spectrum associated with COVID-19: A systematic review and meta-analysis

BACKGROUND AND PURPOSE

Mounting evidence supports an association between Guillain-Barré syndrome spectrum (GBSs) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. However, GBSs in the setting of coronavirus disease 2019 (COVID-19) remains poorly characterized, whilst GBSs prevalence amongst COVID-19 patients has not been previously systematically evaluated using a meta-analytical approach.

METHODS

A systematic review and meta-analysis of observational cohort and case series studies reporting on the occurrence, clinical characteristics and outcomes of patients with COVID-19-associated GBSs was performed. A random-effects model was used to calculate pooled estimates and odds ratios (ORs) with corresponding 95% confidence intervals (CIs), compared to non-COVID-19, contemporary or historical GBSs patients.

RESULTS

Eighteen eligible studies (11 cohorts, seven case series) were identified including a total of 136,746 COVID-19 patients. Amongst COVID-19 patients, including hospitalized and non-hospitalized cases, the pooled GBSs prevalence was 0.15‰ (95% CI 0%-0.49‰; I2  = 96%). Compared with non-infected contemporary or historical controls, patients with SARS-CoV-2 infection had increased odds for demyelinating GBSs subtypes (OR 3.27, 95% CI 1.32%-8.09%; I2  = 0%). In SARS-CoV-2-infected patients, olfactory or concomitant cranial nerve involvement was noted in 41.4% (95% CI 3.5%-60.4%; I2  = 46%) and 42.8% (95% CI 32.8%-53%; I2  = 0%) of the patients, respectively. Clinical outcomes including in-hospital mortality were comparable between COVID-19 GBSs patients and non-infected contemporary or historical GBSs controls.

CONCLUSION

GBSs prevalence was estimated at 15 cases per 100,000 SARS-CoV-2 infections. COVID-19 appears to be associated with an increased likelihood of GBSs and with demyelinating GBSs variants in particular.

Silent SARS-CoV-2 Infections, Waning Immunity, Serology Testing, and COVID-19 Vaccination: A Perspective

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus causes a spectrum of clinical manifestations, ranging from asymptomatic to mild, moderate, or severe illness with multi-organ failure and death. Using a new machine learning algorithm developed by us, we have reported a significantly higher number of predicted COVID-19 cases than the documented counts across the world. The sole reliance on confirmed symptomatic cases overlooking the symptomless COVID-19 infections and the dynamics of waning immunity may not provide 'true' spectrum of infection proportion, a key element for an effective planning and implementation of protection and prevention strategies. We and others have previously shown that strategic orthogonal testing and leveraging systematic data-driven modeling approach to account for asymptomatics and waning cases may situationally have a compelling role in informing efficient vaccination strategies beyond prevalence reporting. However, currently Centers for Disease Control and Prevention (CDC) does not recommend serological testing either before or after vaccination to assess immune status. Given the 27% occurrence of breakthrough infections in fully vaccinated (FV) group with many being asymptomatics and still a larger fraction of the general mass remaining unvaccinated, the relaxed mask mandate and distancing by CDC can drive resurgence. Thus, we believe it is a key time to focus on asymptomatics (no symptoms) and oligosymptomatics (so mild that the symptoms remain unrecognized) as they can be silent reservoirs to propagate the infection. This perspective thus highlights the need for proactive efforts to reevaluate the current variables/strategies in accounting for symptomless and waning fractions.

Kabasura Kudineer (KSK), a poly-herbal Siddha medicine, reduced SARS-CoV-2 viral load in asymptomatic COVID-19 individuals as compared to vitamin C and zinc supplementation: findings from a prospective, exploratory, open-labeled, comparative, randomized controlled trial, Tamil Nadu, India

INTRODUCTION

Despite several ongoing efforts in biomedicine and traditional medicine, there are no drugs or vaccines for coronavirus disease 2019 (COVID-19) as of May 2020; Kabasura Kudineer (KSK), a polyherbal formulation from India's Siddha system of medicine, has been traditionally used for clinical presentations similar to that of COVID-19. We explored the efficacy of KSK in reducing viral load and preventing the disease progression in asymptomatic, COVID-19 cases.

METHODS

A prospective, single-center, open-labeled, randomized, controlled trial was conducted in a COVID Care Centre in Chennai, India. We recruited reverse-transcription polymerase chain reaction (RT-PCR)-confirmed COVID-19 of 18 to 55 years of age, without clinical symptoms and co-morbidities. They were randomized (1:1 ratio) to KSK (60 mL twice daily for 7 days) or standard of care (7 days supplementation of vitamin C 60,000 IU morning daily and zinc 100 mg evening daily) groups. The primary outcomes were reduction in the SARS-CoV-2 load [as measured by cyclic threshold (CT) value of RT-PCR], prevention of progression of asymptomatic to symptomatic state, and changes in the immunity markers including interleukins (IL-6, IL-10, IL-2), interferon gamma (IFNγ), and tumor necrosis factor (TNF α). Siddha clinical assessment and the occurrence of adverse effects were documented as secondary outcomes. Paired t-test was used in statistical analysis.

RESULTS

Viral load in terms of the CT value (RdRp: 95% CI = 1.89 to 5.74) declined significantly on the seventh day in the KSK group and that of the control group, more pronounced in the study group. None progressed to the symptomatic state. There was no significant difference in the biochemical parameters. We did not observe any changes in the Siddha-based clinical examination and adverse events in both groups.

CONCLUSION

KSK significantly reduced SARS-CoV-2 viral load among asymptomatic COVID-19 cases and did not record any adverse effect, indicating the use of KSK in the strategy against COVID-19. Larger, multi-centric trials can strengthen the current findings.

TRIAL REGISTRATION

Clinical Trial Registry of India CTRI2020/05/025215 . Registered on 16 May 2020.

Underdetection in a stochastic SIR model for the analysis of the COVID-19 Italian epidemic

We propose a way to model the underdetection of infected and removed individuals in a compartmental model for estimating the COVID-19 epidemic. The proposed approach is demonstrated on a stochastic SIR model, specified as a system of stochastic differential equations, to analyse data from the Italian COVID-19 epidemic. We find that a correct assessment of the amount of underdetection is important to obtain reliable estimates of the critical model parameters. The adaptation of the model in each time interval between relevant government decrees implementing contagion mitigation measures provides short-term predictions and a continuously updated assessment of the basic reproduction number.

Incidence, Clinical Characteristics, and Risk Factors of SARS-CoV-2 Infection among Pregnant Individuals in the United States

BACKGROUND

Data about the risk of SARS-CoV-2 infection among pregnant individuals are needed to inform infection prevention guidance and counseling for this population.

METHODS

We prospectively followed a cohort of pregnant individuals during August 2020-March 2021 at three U.S. sites. The three primary outcomes were incidence rates of any SARS-CoV-2 infection, symptomatic infection, and asymptomatic infection, during pregnancy during periods of SARS-CoV-2 circulation. Participants self-collected weekly mid-turbinate nasal swabs for SARS-CoV-2 RT-PCR testing, completed weekly illness symptom questionnaires, and submitted additional swabs with COVID-19-like symptoms. An overall SARS-CoV-2 infection incidence rate weighted by population counts of women of reproductive age in each state was calculated.

RESULTS

Among 1098 pregnant individuals followed for a mean of 10 weeks, nine percent (99/1098) had SARS-CoV-2 infections during the study. Population weighted incidence rates of SARS-CoV-2 infection were 10.0 per 1,000 (95% confidence interval [CI] 5.7-14.3) person-weeks for any infection, 5.7 per 1,000 (95% CI 1.7-9.7) for symptomatic infections, and 3.5 per 1,000 (95% CI 0-7.1) for asymptomatic infections. Among 96 participants with SARS-CoV-2 infection and symptom data, the most common symptoms were nasal congestion (72%), cough (64%), headache (59%), and change in taste or smell (54%); 28% had measured or subjective fever. The median symptom duration was 10 days (IQR6-16 days).

CONCLUSION

Pregnant individuals had a 1% risk of SARS-CoV-2 infection per week. Study findings provide information about SARS-CoV-2 infection risk during pregnancy to inform counseling for pregnant individuals about infection prevention practices, including COVID-19 vaccination.

Possible Use of Phytochemicals for Recovery from COVID-19-Induced Anosmia and Ageusia

The year 2020 became the year of the outbreak of coronavirus, SARS-CoV-2, which escalated into a worldwide pandemic and continued into 2021. One of the unique symptoms of the SARS-CoV-2 disease, COVID-19, is the loss of chemical senses, i.e., smell and taste. Smell training is one of the methods used in facilitating recovery of the olfactory sense, and it uses essential oils of lemon, rose, clove, and eucalyptus. These essential oils were not selected based on their chemical constituents. Although scientific studies have shown that they improve recovery, there may be better combinations for facilitating recovery. Many phytochemicals have bioactive properties with anti-inflammatory and anti-viral effects. In this review, we describe the chemical compounds with anti- inflammatory and anti-viral effects, and we list the plants that contain these chemical compounds. We expand the review from terpenes to the less volatile flavonoids in order to propose a combination of essential oils and diets that can be used to develop a new taste training method, as there has been no taste training so far. Finally, we discuss the possible use of these in clinical settings.

Impact of natural selection on global patterns of genetic variation, and association with clinical phenotypes, at genes involved in SARS-CoV-2 infection

We investigated global patterns of genetic variation and signatures of natural selection at host genes relevant to SARS-CoV-2 infection ( ACE2, TMPRSS2, DPP4 , and LY6E ). We analyzed novel data from 2,012 ethnically diverse Africans and 15,997 individuals of European and African ancestry with electronic health records, and integrated with global data from the 1000GP. At ACE2 , we identified 41 non-synonymous variants that were rare in most populations, several of which impact protein function. However, three non-synonymous variants were common among Central African hunter-gatherers from Cameroon and are on haplotypes that exhibit signatures of positive selection. We identify strong signatures of selection impacting variation at regulatory regions influencing ACE2 expression in multiple African populations. At TMPRSS2 , we identified 13 amino acid changes that are adaptive and specific to the human lineage. Genetic variants that are targets of natural selection are associated with clinical phenotypes common in patients with COVID-19.

Comparison of Estimated Effectiveness of Case-Based and Population-Based Interventions on COVID-19 Containment in Taiwan

IMPORTANCE

Taiwan is one of the few countries with initial success in COVID-19 control without strict lockdown or school closure. The reasons remain to be fully elucidated.

OBJECTIVE

To compare and evaluate the effectiveness of case-based (including contact tracing and quarantine) and population-based (including social distancing and facial masking) interventions for COVID-19 in Taiwan.

DESIGN, SETTING, AND PARTICIPANTS

This comparative effectiveness study used a stochastic branching process model using COVID-19 epidemic data from Taiwan, an island nation of 23.6 million people, with no locally acquired cases of COVID-19 reported for 253 days between April and December 2020.

MAIN OUTCOMES AND MEASURES

Effective reproduction number of COVID-19 cases (the number of secondary cases generated by 1 primary case) and the probability of outbreak extinction (0 new cases within 20 generations). For model development and calibration, an estimation of the incubation period (interval from exposure to symptom onset), serial interval (time between symptom onset in an infector-infectee pair), and the statistical distribution of the number of any subsequent infections generated by 1 primary case was calculated.

RESULTS

This study analyzed data from 158 confirmed COVID-19 cases (median age, 45 years; interquartile range, 25-55 years; 84 men [53%]). An estimated 55% (95% credible interval [CrI], 41%-68%) of transmission events occurred during the presymptomatic stage. In our estimated analysis, case detection, contact tracing, and 14-day quarantine of close contacts (regardless of symptoms) was estimated to decrease the reproduction number from the counterfactual value of 2.50 to 1.53 (95% CrI, 1.50-1.57), which would not be sufficient for epidemic control, which requires a value of less than 1. In our estimated analysis, voluntary population-based interventions, if used alone, were estimated to have reduced the reproduction number to 1.30 (95% CrI, 1.03-1.58). Combined case-based and population-based interventions were estimated to reduce the reproduction number to below unity (0.85; 95% CrI, 0.78-0.89). Results were similar for additional analyses with influenza data and sensitivity analyses.

CONCLUSIONS AND RELEVANCE

In this comparative effectiveness research study, the combination of case-based and population-based interventions (with wide adherence) may explain the success of COVID-19 control in Taiwan in 2020. Either category of interventions alone would have been insufficient, even in a country with an effective public health system and comprehensive contact tracing program. Mitigating the COVID-19 pandemic requires the collaborative effort of public health professionals and the general public.

Clinical and Economic Effects of Widespread Rapid Testing to Decrease SARS-CoV-2 Transmission

BACKGROUND

The value of frequent, rapid testing to reduce community transmission of SARS-CoV-2 is poorly understood.

OBJECTIVE

To define performance standards and predict the clinical, epidemiologic, and economic outcomes of nationwide, home-based antigen testing.

DESIGN

A simple compartmental epidemic model that estimated viral transmission, portrayed disease progression, and forecast resource use, with and without testing.

DATA SOURCES

Parameter values and ranges as informed by Centers for Disease Control and Prevention guidance and published literature.

TARGET POPULATION

U.S. population.

TIME HORIZON

60 days.

PERSPECTIVE

Societal; costs included testing, inpatient care, and lost workdays.

INTERVENTION

Home-based SARS-CoV-2 antigen testing.

OUTCOME MEASURES

Cumulative infections and deaths, number of persons isolated and hospitalized, and total costs.

RESULTS OF BASE-CASE ANALYSIS

Without a testing intervention, the model anticipates 11.6 million infections, 119 000 deaths, and $10.1 billion in costs ($6.5 billion in inpatient care and $3.5 billion in lost productivity) over a 60-day horizon. Weekly availability of testing would avert 2.8 million infections and 15 700 deaths, increasing costs by $22.3 billion. Lower inpatient outlays ($5.9 billion) would partially offset additional testing expenditures ($12.5 billion) and workdays lost ($14.0 billion), yielding incremental cost-effectiveness ratios of $7890 per infection averted and $1 430 000 per death averted.

RESULTS OF SENSITIVITY ANALYSIS

Outcome estimates vary widely under different behavioral assumptions and testing frequencies. However, key findings persist across all scenarios, with large reductions in infections, mortality, and hospitalizations. Costs per death averted are roughly an order of magnitude lower than commonly accepted willingness-to-pay values per statistical life saved ($5 to $17 million).

LIMITATIONS

Analysis was restricted to at-home testing. There are uncertainties concerning test performance.

CONCLUSION

High-frequency home testing for SARS-CoV-2 with an inexpensive, imperfect test could contribute to pandemic control at justifiable cost and warrants consideration as part of a national containment strategy.

PRIMARY FUNDING SOURCE

National Institutes of Health.

Coronavirus disease 2019 respiratory disease in children: clinical presentation and pathophysiology

PURPOSE OF REVIEW

Pediatric coronavirus disease 2019 (COVID-19) respiratory disease is a distinct entity from adult illness, most notable in its milder phenotype. This review summarizes the current knowledge of the clinical patterns, cellular pathophysiology, and epidemiology of COVID-19 respiratory disease in children with specific attention toward factors that account for the maturation-related differences in disease severity.

RECENT FINDINGS

Over the past 14 months, knowledge of the clinical presentation and pathophysiology of COVID-19 pneumonia has rapidly expanded. The decreased disease severity of COVID-19 pneumonia in children was an early observation. Differences in the efficiency of viral cell entry and timing of immune recognition and response between children and adults remain at the center of ongoing research.

SUMMARY

The clinical spectrum of COVID-19 respiratory disease in children is well defined. The age-related differences protecting children from severe disease and death remain incompletely understood.

Pitfall of Universal Pre-Admission Screening for SARS-CoV-2 in a Low Prevalence Country

It is unclear whether universal PCR screening for SARS-CoV-2 in asymptomatic individuals prior to admission is useful. From April to December 2020, the positive rate of universal pre-admission screening was 0.005% (4/76,521) in a tertiary care hospital in Korea. The positive rates were not different between the periods (period 1 (daily new patients of <1 per million inhabitants) vs. period 2 (1-8.3 per million inhabitants) vs. period 3 (10.3 to 20 per million inhabitants); P = 0.45). Universal pre-admission screening for SARS-CoV-2 had a lower positive rate than that of symptom-based screening (0.005% vs. 0.049% (53/109,257), p < 0.001). In addition, seven patients with negative pre-admission test results had subsequent positive PCR during hospitalization, and four patients had secondary transmission. Universal pre-admission PCR screening may not be practical in settings of low prevalence of COVID-19, and negative PCR results at admission should not serve as a basis for underestimating the risk of nosocomial spread from asymptomatic patients.

Asymptomatic Cases, the Hidden Challenge in Predicting COVID-19 Caseload Increases

The numbers of novel coronavirus cases continue to grow at an unprecedented rate across the world. Attempts to control the growth of the virus using masks and social-distancing, and, recently, double-masking as well, continue to be difficult to maintain, in part due to the extent of asymptomatic cases. Analyses of large datasets consisting of 219,075 individual cases in Ontario, indicated that asymptomatic and pre-symptomatic cases are substantial in number. Large numbers of cases in children aged 0-9 were asymptomatic or had only one symptom (35.0% and 31.4% of total cases, respectively) and resulted in fever as the most common symptom (30.6% of total cases). COVID-19 cases in children were more likely to be milder symptomatic with cough not seen as frequently as in adults aged over 40, and past research has shown children to be index cases in familial clusters. These findings highlight the importance of targeting asymptomatic and mild infections in the continuing effort to control the spread of COVID-19. The Pearson correlation coefficient between test positivity rates and asymptomatic rates of -0.729 indicates that estimates of the asymptomatic rates should be obtained when the test positivity rates are lowest as the best approach.