The impact of COVID-19 epidemic on the control of important parasitic diseases.

The spread of COVID-19 has increased the risk of contact transmission between people, and imposes challenges and opportunities for the prevention and control of important parasitic diseases. There may be risks of COVID-19 infection during the implementation of the virus control, including in field investigation and intervention, contacting with fecal samples, or with asymptomatic infected people. Therefore, corresponding prevention and control measures should be taken before and during field investigation, and in sample transportation and detection to prevent the risks effectively. In this paper, the risks and corresponding countermeasures in the above processes are discussed in detail, and the opportunities that COVID-19 brought to the disease control system are also analyzed.Copyright © 2021, National Institute of Parasitic Diseases. All rights reserved.

On clinical manifestations of the new coronavirus infection in newborns.

The aim of the research. To study the specifics in manifestations of the new coronavirus infection in newborns. Material and methods. A retrospective analysis of observations of 28 newborns diagnosed with the new coronavirus infection SARS-CoV-2 dated from June to December 2020 was performed. The infants were transferred from the perinatal centre for hospitalisation to the infectious department of a children's hospital. The patients were born to mothers with COVID-19 as well as mothers discharged from hospital and hospitalised later due to COVID-19 acquired through family contact. Clinical and laboratory data of 12 female and 16 male children aged 1 to 28 days were studied. Results. Clinical symptoms of the new coronavirus infection in newborns tend to be different: from asymptomatic course in 46.5 % of the patients to evident pneumonia in 50 % of the children. The newborns admitted with COVID-19 acquired through family contact had more severe disease manifestations. Conclusion. Amidst the pandemic rise of its incidence, the new coronavirus infection COVID-19 is not rare among newborns. COVID-19 newborns did not have a registered severe nosocomial infection, sepsis, multisystem inflammatory syndrome.Copyright © 2022, Krasnoyarsk State Medical University. All rights reserved.

A COVID-19 Infection Model Considering the Factors of Environmental Vectors and Re-Positives and Its Application to Data Fitting in Japan and Italy.

COVID-19, which broke out globally in 2019, is an infectious disease caused by a novel strain of coronavirus, and its spread is highly contagious and concealed. Environmental vectors play an important role in viral infection and transmission, which brings new difficulties and challenges to disease prevention and control. In this paper, a type of differential equation model is constructed according to the spreading functions and characteristics of exposed individuals and environmental vectors during the virus infection process. In the proposed model, five compartments were considered, namely, susceptible individuals, exposed individuals, infected individuals, recovered individuals, and environmental vectors (contaminated with free virus particles). In particular, the re-positive factor was taken into account (i.e., recovered individuals who have lost sufficient immune protection may still return to the exposed class). With the basic reproduction number R0 of the model, the global stability of the disease-free equilibrium and uniform persistence of the model were completely analyzed. Furthermore, sufficient conditions for the global stability of the endemic equilibrium of the model were also given. Finally, the effective predictability of the model was tested by fitting COVID-19 data from Japan and Italy.

Investigation of imported malaria cases at a COVID-19 isolation point in Qingdao

The epidemiological data were collected from travellers who returned from Guinea on the 23rd of September, 2020 and were diagnosed with malaria at a C OVID -19 quarantine site in Qingdao, Shandong Province. The epidemiological characteristics, diagnosis and treatment of the cases and the epidemiology investigation and the rapid test screening results for other travellers on from the same flight and the interventions in reaction to the imported malaria cases were analyzed. The results showed that 4 out of 231 Guinean returned travellers had developed malaria symptoms, including chills and fever, during the isolation period. Rapid diagnostic test (RDT) indicated Plasmodium falciparum infection. Considering the patients ' travel history, clinical manifestations, and laboratory RDT test results, a confirmed diagnosis of imported P. falciparum malaria was made. The four malaria cases, who are male workers aged 29 to 55, were transferred to Jiaozhou People ' s Hospital for treatment. All four patients were administrated of artemether tablets upon diagnosis. One of the cases experienced severe malaria complications and were administrated with 12 doses (60 mg/dose) of artesunate intravenously for five days. The other three patients were treated with dihydroartemisinin and piperaquine phosphate tablets for one course of 8 tablets in 2 days (40 mg dihydroartemisinin and 320 mg piperaquine phosphate), respectively. Among the 231 returned travellers, 111 (48.1 %) had a history of malaria overseas. There were 23 positive cases detected by RDT, including the four symptomatic cases. The other 19 cases were asymptomatic. One of the asymptomatic cases became symptomatic three months later and was diagnosed as an imported P. malariae infection. Laboratory blood smear microscopic tests at the Jiaozhou City and Qingdao Municipal Center For Disease Control and Prevention showed negative results for the four malaria cases and the 19 RDT positive case. The samples from the four malaria cases were rechecked by the provincial reference laboratory of Shandong Institute of parasitic Disease. The results were negative for malaria infection by microscopic examination but positive for P. falciparum infection by nucleic acid test. It is suggested that during the routine control of COVID-19, the awareness of COVID-19 and malaria should be established among the returned travellers from high malaria-endemic areas. The health education "gate" should be moved forward to improve the treatment compliance for malaria cases and reduce the relapse or recrudescence caused by sub-optimal treatment.Copyright © 2022, Chin J Parasitol Parasit Dis. All rights reserved.

Covid-19 Associated Hepatitis in Children (Cah-C) during the Rise of Delta Variant in India: A New Covid-19 Complication or a Superinfection

Intro: While the pediatric population has largely remained free of severe COVID- 19, in some situations SARS-CoV-2 infection has been associated with complications like Multiple Inflammatory Syndrome in children (MIS-C). Recently, cases of hepatitis in children have caused tremendous worry across the globe, we describe a unique presentation from 2021, subsequent to asymptomatic infection of SARS-CoV-2, a unique form of severe hepatitis designated by us as COVID-19 Associated Hepatitis in Children (CAH-C). The clinical presentations, temporal association, and viral parameters of CAH-C cases, and contrast to that of MIS-C cases are presented here. Method(s): As a retrospective and follow-up case-control study we reviewed all children within 14 years presenting with "sudden onset of hepatitis, elevated transaminases, non-obstructive jaundice. After performing all routine tests among them, those lacking marked inflammatory responses and without evidence of (a) other known causes of acute hepatitis (A-E) or previous underlying liver disease, and (b) multi-system involvement", being unique such cases were classified as CAH-C, and are described here. Finding(s): Among 475 children who tested positive, 37/47 cases had features of CAH-C, having symptoms of hepatitis only, with un-elevated inflammatory markers, 100% positivity for SARS-CoV-2 antibodies, and uneventful recovery. The remaining 10/47 having MIS-C had protracted illness, multiple system involvement, required admission to critical care, and a mortality rate of 30%. Among controls, only 26/50 (52%) had SARS-CoV-2 antibodies. Discussion(s): During the pandemic, various COVID-19 complications have been observed posing safety concerns, where our study identified a unique form of acute hepatitis in children designated as CAH-C. Conclusion(s): With the emergence of newer variants, including the Delta variant which predominated the second wave of infections in India and spread worldwide with changing presentations and complications, CAH-C is such new entity in children. It needs early identification and differentiation from other emerging syndromes during the ongoing pandemic for preventing adversities through timely intervention.Copyright © 2023

Influence of setting-dependent contacts and protective behaviours on asymptomatic SARS-CoV-2 infection amongst members of a UK university.

We survey 62 users of a university asymptomatic SARS-CoV-2 testing service on details of their activities, protective behaviours and contacts in the 7 days prior to receiving a positive or negative SARS-CoV-2 PCR test result in the period October 2020-March 2021. The resulting data set is novel in capturing very detailed social contact history linked to asymptomatic disease status during a period of significant restriction on social activities. We use this data to explore 3 questions: (i) Did participation in university activities enhance infection risk? (ii) How do contact definitions rank in their ability to explain test outcome during periods of social restrictions? (iii) Do patterns in the protective behaviours help explain discrepancies between the explanatory performance of different contact measures? We classify activities into settings and use Bayesian logistic regression to model test outcome, computing posterior model probabilities to compare the performance of models adopting different contact definitions. Associations between protective behaviours, participant characteristics and setting are explored at the level of individual activities using multiple correspondence analysis (MCA). We find that participation in air travel or non-university work activities was associated with a positive asymptomatic SARS-CoV-2 PCR test, in contrast to participation in research and teaching settings. Intriguingly, logistic regression models with binary measures of contact in a setting performed better than more traditional contact numbers or person contact hours (PCH). The MCA indicates that patterns of protective behaviours vary between setting, in a manner which may help explain the preference for any participation as a contact measure. We conclude that linked PCR testing and social contact data can in principle be used to test the utility of contact definitions, and the investigation of contact definitions in larger linked studies is warranted to ensure contact data can capture environmental and social factors influencing transmission risk.

Prevalence of Asymptomatic COVID-19 Infection in Hemodialysis Patients and the Risk of Hypercoagulability: Should we Consider Routine Screening?

Introduction: Coronavirus disease 2019 (COVID-19) has become a pandemic in late 2019. Its clinical presentation varies from asymptomatic infection to severe respiratory failure. Infection control strategies to minimize the risk of transmission of COVID-19 in end-stage renal disease (ESRD) patients receiving in-center hemodialysis (HD) have been implemented. Development of humoral response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in adult patients with ESRD receiving HD has not been sufficiently reported. Methods: A total of 179 asymptomatic HD patients undergoing regular HD were screened for COVID-19 infection. Infection with SARS-CoV-2 was confirmed through a real-time reverse transcription polymerase chain reaction assay of nasopharyngeal swab specimens. They were classified into positive and negative groups according to the results of PCR. Results: Of the 179 asymptomatic patients, we found that 23 patients (12.8%) were positive for COVID-19. Their mean age was 45.61 ± 13.38 years. There was a significant difference between both groups regarding C-reactive protein, lymphocytes, and platelet counts (P < 0.001). Also, TAT (thrombin-antithrombin complex) and D-dimer levels were significantly increased among the positive group (11.47 ± 1.51 vs. 7.53 ± 1.64 mcq/L, P < 0.001; 1171.52 ± 267.6 vs. 542.76 ± 107.06 ng/mL, P < 0.001, respectively). Conclusion: Asymptomatic SARS-CoV-2 infection is detected in HD patients. They carry the risk of hypercoagulability complications. We need more strict infection control measures and proactive diagnosis to limit the spread of the infection and lethal thromboembolic complications.

Memory B cell development after asymptomatic or mild symptomatic SARS-CoV-2 infection.

BACKGROUND: The development of memory B cells after asymptomatic SARS-CoV-2 infection is not well understood. METHODS: We compared Spike antibody titers, pseudovirus neutralizing antibody titers, and memory B cell responses among SARS-CoV-2 PCR positive Marine recruits who either reported asymptomatic or symptomatic infection. RESULTS: 36 asymptomatic participants exhibited similar Spike IgG titers, Spike IgA titers, and pseudovirus neutralization titers compared to 30 symptomatic participants. Pseudovirus neutralization and Spike IgG titers showed significant positive correlations with frequency of memory B cells. CONCLUSIONS: Among young adults, asymptomatic SARS-CoV-2 infection induced antibody and memory B cell responses comparable to mild symptomatic infection.

Vaccination status for mild and asymptomatic infections with SARS-CoV-2 Omicron BA.2 variant in Shanghai.

This study aimed to evaluate the effects of different vaccine regimens on mild and asymptomatic infections with SARS-CoV-2 Omicron BA.2 variant in Shanghai. All asymptomatic patients and those with mild symptoms of Omicron infections were recruited from three major Fangcang shelter hospitals between March 26, 2022 and May 20, 2022. Nucleic acid for SARS-CoV-2 by real-time reverse-transcription polymerase chain reaction methods in nasopharyngeal swabs was assessed every day during the hospitalization. The value of cycle threshold lower than 35 was considered as positive result of SARS-CoV-2. A total of 214 592 cases were included in this study. The proportion of the asymptomatic patients was 76.90% and 23.10% of the recruited patients had mild symptoms. The median (interquartile range [IQR]: 25-75) duration of viral shedding (DVS) was 7 (5-10) days among all participants. The DVS varied greatly among different age groups. Children and the elderly had longer DVS compared with the adults. The booster shot of inactivated vaccine contributed to the shorter DVS in patients aged ≥70 years compared with the unvaccinated patients (8 [6-11] vs. 9 [6-12] days, p = 0.002]. Full inactivated vaccine regimen contributed to the shorter DVS in patients aged 3-6 years (7 [5-9] vs. 8 [5-10] days, p = 0.001]. In conclusion, the full inactivated vaccine regimen on children aged 3-6 years and booster inactivated vaccine regimen on the elderly aged ≥70 years appeared to be effective in reducing DVS. The booster vaccine regimen should be rigorously promoted and implemented.

Excreción de SARS-CoV-2 infeccioso en dos niños asintomáticos

Asymptomatic infections with SARS-CoV-2 are associated with viral transmission and have a key role in the propagation of the pandemic. Understanding viral shedding during asymptomatic infections is critical. Unfortunately, data on asymptomatic SARS-CoV-2 infection in children is extremely limited. To determine the presence of viral viable shedding, we prospectively followed two healthy children of a family where both parents developed mild COVID-19 (April 2021). SARS-CoV-2 detection was made by RT-PCR and virus isolation by cell culture from saliva samples. Positive samples were sequenced to identify variants of SARS-CoV-2. Serum samples were evaluated to determine the presence of antibodies using a single enzyme-linked immunosorbent assay (ELISA, COVIDAR IgG). Both children were SARS-CoV-2 positive and asymptomatic. In addition, the virus grew in cell culture from saliva samples. Furthermore, one child showed viable SARS-CoV-2 for at least 17 days after the onset symptoms from his father. The recommended isolation period for asymptomatic contacts during the acquisition of data had been established for 10 days;however, this child remained with viable virus beyond that period. The positive samples from both children were consistent with B.1.1.28.1 lineage (Gamma). In both asymptomatic children, anti-Spike IgG was detected. Asymptomatic children may represent a source of infection that should not be underestimated during this pandemic. Las infecciones asintomáticas por SARS-CoV-2 están asociadas a la transmisión viral y tienen un papel clave en la propagación de la pandemia. Comprender la excreción viral durante las infecciones asintomáticas es fundamental. Desafortunadamente, los datos sobre la infección asintomática por SARS-CoV-2 en niños son extremadamente limitados. Para determinar la presencia de excreción de virus viable, se siguió prospectivamente a dos niños sanos de una familia en la que ambos padres desarrollaron COVID-19 leve (abril 2021). La detección de SARS-CoV-2 se realizó por RT-PCR y el aislamiento del virus por cultivo celular a partir de muestras de saliva. Las muestras positivas se secuenciaron para identificar variantes de SARS-CoV-2. En las muestras de suero se determinó la presencia de anticuerpos utilizando un ensayo de ELISA (COVIDAR IgG). Ambos niños fueron positivos para SARS-CoV-2 y asintomáticos. Además, el virus creció en cultivos celulares a partir de muestras de saliva. Uno de los niños mantuvo SARS-CoV-2 viables durante al menos 17 días después de la aparición de los síntomas de su padre. El período de aislamiento recomendado para contactos asintomáticos durante la adquisición de datos se había establecido en 10 días, sin embargo, este niño permaneció con virus viable más allá de ese período. Las muestras positivas de estos niños correspondieron al linaje B.1.1.28.1 (Gamma). En ambos niños asintomáticos se detectó anticuerpos IgG anti-Spike. Concluimos que los niños asintomáticos pueden representar una fuente de infección que no debe subestimarse durante esta pandemia.

SARS CoV-2 seroprevalence and diagnostic accuracy during a COVID-19 outbreak in a major penitentiary complex in Brazil, June to July 2020

PurposeThis study aims to estimate the overall SARS-CoV-2 seroprevalence and evaluate the accuracy of an antibody rapid test compared to a reference serological assay during a COVID-19 outbreak in a prison complex housing over 13,000 prisoners in Brasília.Design/methodology/approachThe authors obtained a randomized, stratified representative sample of each prison unit and conducted a repeated serosurvey among prisoners between June and July 2020, using a lateral-flow immunochromatographic assay (LFIA). Samples were also retested using a chemiluminescence enzyme immunoassay (CLIA) to compare SARS-CoV-2 seroprevalence and 21-days incidence, as well as to estimate the overall infection fatality rate (IFR) and determine the diagnostic accuracy of the LFIA test.FindingsThis study identified 485 eligible individuals and enrolled 460 participants. Baseline and 21-days follow-up seroprevalence were estimated at 52.0% (95% CI 44.9–59.0) and 56.7% (95% CI 48.2–65.3) with LFIA;and 80.7% (95% CI 74.1–87.3) and 81.1% (95% CI 74.4–87.8) with CLIA, with an overall IFR of 0.02%. There were 78.2% (95% CI 66.7–89.7) symptomatic individuals among the positive cases. Sensitivity and specificity of LFIA were estimated at 43.4% and 83.3% for IgM;46.5% and 91.5% for IgG;and 59.1% and 77.3% for combined tests.Originality/valueThe authors found high seroprevalence of anti-SARS-CoV-2 antibodies within the prison complex. The occurrence of asymptomatic infection highlights the importance of periodic mass testing in addition to case-finding of symptomatic individuals;however, the field performance of LFIA tests should be validated. This study recommends that vaccination strategies consider the inclusion of prisoners and prison staff in priority groups.

SARS-CoV-2 VACCINE EFFECTIVENESS IN A COHORT OF ACTIVE-DUTY US MILITARY PERSONNEL

Background: The US Defense Dept launched its COVID-19 vaccination program in Dec 20. The VIRAMP study was designed to address knowledge gaps in US military personnel including vaccine effectiveness against asymptomatic infection, viral carriage and transmission, and durability of protection. Method(s): Military members who had received >=1 dose of an FDA-authorized COVID-19 vaccine were enrolled at 3 sites in Texas May 21-Mar 22 and followed for up to 24 months after first dose. Study activities comprised of three in-person study visits and remote data collection: weekly and monthly questionnaires, self-collection of blood (monthly) and saliva twice weekly (more frequently if symptomatic). Participants shipped self-collected specimens for Ab analyses and SARS-CoV-2 PCR and sequencing. We report an interim analysis on data collected through May 22. Result(s): Participants included 957 military members (60% male, 40% female), with 69% identifying as White, 15% Black/African American, 23% LatinX. Participants were Officers (38%) and Enlisted (62%);54% were healthcare workers. The majority (92.5%) received the Pfizer/BioNTech monovalent A/ Wuhan COVID-19 vaccine;30% of participants received one booster dose. One or more breakthrough infections (bti), defined as positive saliva SARS-CoV-2 PCR, were detected in 228 (24%) participants (36 Delta, 192 Omicron). No differences were detected in rates of symptomatic vs asymptomatic bti by variant or time since last vaccine. Mean age was greater for participants with bti vs those without (35.4 (+/- 7.7) years vs 32 (+/- 8.2) years;p< 0.0001), but no differences were noted by sex, race, or ethnicity. Symptomatic infections (defined as >=2 symptoms) were detected in 43% of participants, whereas 35% of bti were asymptomatic;there were no hospitalizations or deaths. A trend towards reduced duration of saliva positivity was noted in Omicron infections in the 4 months following booster dose compared to infections in the 4 months following primary series (5.3 days vs 12.4 days;p=0.0645). Conclusion(s): Approximately 1/4 of participants had bti in the first year, spanning the evolving epi and vaccination landscape of the pandemic, with about 1/3 demonstrating asymptomatic infection. A trend towards shorter duration of viral carriage following booster dose was noted in Omicron infections. The VIRAMP study demonstrated that prospective surveillance in a large, diverse cohort of US military members utilizing remote specimen and questionnaire collection is operationally feasible.

DELINEATING FACTORS ASSOCIATED WITH ASYMPTOMATIC PRIMARY SARS-CoV-2 INFECTION

Background: SARS-CoV-2 infection leads to a broad range of clinical manifestations, from no symptoms to critical illness. Pre-stimulated innate defenses, rapid induction of SARS-CoV-2 responses and pre-existing crossreactive immunity to circulating human coronaviruses (HCoV) may early dampen SARS-CoV-2 infection, preventing symptomatic disease. Here we explore SARS-CoV-2 and HCoV antibody impact on asymptomatic infection in individuals first encountering SARS-CoV-2 in March 2020-March 2021 participating in a longitudinal pediatric cohort (n=2917) and a cross-sectional adult and children diagnostic cohort (n=882) in Switzerland. Method(s): Antibodies (Ab) to S1 of the four HCoV strains and SARS-CoV-2 antigens S1, RBD, S2 and N were determined in saliva (n=4993) and serum (n=7486) samples. Mucosal and systemic neutralization activity against wildtype SARS-CoV-2-Wuhan, and Alpha, Delta and Omicron (BA.2) variants of concerns (VoC) was assessed by pseudovirus neutralization in a subset of individuals. Result(s): Analysis of simultaneously sampled saliva and plasma revealed a strong correlation of mucosal and systemic SARS-CoV-2 anti-spike responses in recent infection. Notably, pre-existing high HCoV antibody response was significantly associated with higher systemic (IgG, IgA, and IgM, p< 0.001) and mucosal (IgG, p=0.03) SARS-CoV-2 responses following SARS-CoV-2 infection. Adjusting for age and sex, we found four saliva SARS-CoV-2 Ab parameters, namely total Ig S2, total Ig S1, IgA S2 and IgM S1 (p< 0.001, p< 0.001, p=0.02, p=0.01 respectively), inversely associated with salivary viral load highlighting the impact of mucosal Ab response on viral suppression. Saliva neutralization activity was modest but surprisingly broad, retaining same level activity against Wuhan, Alpha and Delta, but not Omicron BA.2, whereas plasma neutralization activity showed the typical decrease for all three VoCs compared to Wuhan. Most interestingly, asymptomatic individuals presented with higher IgG S2 antibody reactivity in saliva (p=0.03) and higher pre-existing HCoV-S1 IgG activity in plasma (HKU1, p=0.04) and saliva (total hCoV, p=0.02) suggesting immune factors that restrict disease severity. Conclusion(s): Focusing on a SARS-CoV-2 infection and vaccine naive population, our study reveals interdependencies of systemic and mucosal SARS-CoV-2 and HCoV immunity following primary SARS-CoV-2 infection and locates reactivities linked with reduced viral load and asymptomatic infection.

RESPIRATORY DISEASE FACTORS LINK WITH REDUCED SARS-CoV-2 SUSCEPTIBILITY IN PWH

Background: Despite favorable vaccine responses of people with HIV (PWH), susceptibility to SARS-CoV-2 (SCv2) infection and increased risk of COVID-19 in immunocompromised PWH continue to be of concern. Here, we searched the Swiss HIV Cohort Study (SHCS) with>9500 actively enrolled, optimally treated PWH to identify factors associated with SCv2 infection in the pre-and postvaccination area. Method(s): We utilized information on SCv2 events reported to the SHCS in 2020 -2021. To detect asymptomatic infection, we screened pre-pandemic (2019) and pandemic (2020-2021) bio-banked plasma for SCv2 antibodies (Ab). SCv2+ and matched SCv2- PWH were additionally screened for Abs to circulating human coronaviruses (HCoV). Data were compared to HIV negative (HIV-) controls. SCv2 data and >26 behavioral, immunologic and disease-parameters available in the SHCS data base were analyzed by logistic regression, conditional logistic regression, and Bayesian multivariate regression. Result(s): Considering information on the SCv2 status of 6270 SHCS participants, neither HIV-1 viral load nor CD4+ T cell levels were linked with increased SCv2 infection risk. COVID-19-linked hospitalization (87/982) and case fatality rates (8/982) were low, but slightly higher than in the general Swiss population when stratified by age. Compared to HIV-, PWH had lower SCv2 IgG responses (median effect size= -0.48, 95%-Credibility-Interval=[-0.7, -0.28]). Consistent with earlier findings, high HCoV Abs pre-pandemic (2019) were associated with a lower risk of a subsequent SCv2-infection and, in case or infection, with higher Ab responses. Examining behavioral factors unrelated to the HIV-status, people living in single-person households were less at risk of SCv2 infection (aOR= 0.77 [0.66,0.9]). We found a striking, highly significant protective effect of smoking on SCv2 infection risk (aOR= 0.46 [0.38,0.56], p=2.6*10-14) which was strongest in 2020 prior to vaccination and was even comparable to the effect of early vaccination in 2021. This impact of smoking was highly robust, occurred even in previous smokers and was highest for heavy smokers. Conclusion(s): Our unbiased cohort screen identified two controversially discussed factors, smoking and cross-protection by HCoV responses to be linked with reduced susceptibility to SCv2, validating their effect for the general population. Overall weaker SCv2 Ab responses in PWH are of concern and need to be monitored to ensure infection- and vaccine-mediated protection from severe disease.

Prevalence of Asymptomatic COVID-19 Infection Among Air Medical Crew

Background: Air medical transport of COVID-19 patients is challenging and presents a high-risk exposure for many air medical crew. Previous investigations have concluded that routine PPE utilized by air medical crew using routing personal protective equipment is safe and effective at preventing symptomatic COVID-19 infections. However, it is unclear to what extent providers may be exposed, contract COVID-19, and remain asymptomatic but potentially contagious. Previous reports suggest up to 6.4% of infected health care personnel are asymptomatic. Method(s): We conducted an IRB approved, primary mixed-methods research study that tested for COVID-19 antibodies in a cohort of participants previously surveyed regarding COVID-19 symptoms. Written consent was obtained by all participants. ELISA testing was performed at the University of New Mexico Center for Global Health Laboratory. Testing included measuring for COVID-19 antibodies in a manner that was independent of vaccination status. Participants also filled out a secure electronic survey to aide in the qualitative data collection and analysis. Result(s): There were 42 participants. Labs samples were obtained between June 2021 and October 2021. Of the 42, 40 were vaccinated (95.2%) and 2 were unvaccinated (4.8%). Of the 40 who were vaccinated, 1 person had the 2-part Moderna vaccine, the rest had the 2-part Pfizer vaccine. 10 of 42 (23.8%) had experienced potential symptoms of COVID-19 at some point in time but had never had a positive test and 32 (76.2%) never experienced any symptoms. Of the 42, 4 had a positive ELISA test for COVID-19 antibody for a positivity rate of 9.52%. Out of the 4 subjects that tested positive, 3 (75%) never experienced any symptoms. Conclusion(s): While the routine use of PPE has been proven to be effective in protecting air medical personnel from symptomatic COVID-19 infection, asymptomatic infection remains a concern. We found that 3 out of 4 that tested positive were asymptomatic. This is significant considering asymptomatic infection poses a risk to air medical crew, patients, coworkers, families, and the general public. Further investigation is required to better ascertain potential gaps in protective equipment or other latent sources of infection that pose risks to air medical crew.Copyright © 2022

Post-infectious serum neutralizing SARS-CoV- 2 anti-S protein specific IgG antibody response and decay over a 6-month 3-point sequential concentrations measurement after COVID-19 infection in health care workers

Background: Healthcare workers (HCW) were heavily exposed to iterative viral loads during SARS-CoV- 2/ COVID-19 pandemic. Post-infectious serum neutralizing anti-S/ SARS-CoV- 2 IgG antibody concentrations (anti-S sIgG), albeit a controversial biomarker of antiviral immune response efficacy is actually the only available in routine clinical practice. Method(s): Sequential serum anti-S sIgG measurement (chemiluminescence immunoassay;cut-off: >=1AU/mL) at 3 time-points: T0 = 50.3 +/- 15.3 days after symptom onset (dSo), 16.8 +/- 12.0 days after quarantine end (dQe);T1 = 143.1 +/- 43.9 dSo, 109.4 +/- 43.0 dQe;T2 = 241.3 +/- 75.5 dSo, 208.6 +/- 75.6 dQe;disease severity was classified as asymptomatic (IS1), mild/moderate (IS2) and severe/very severe (IS3) levels. We've enrolled 177 out of 193 positive SARS-CoV- 2/ RT-PCR HCW (8.3% initial dropout), 76.2% female/mean age = 39.6 +/- 11.7 years (y), 23.8% male/mean age = 41.1 +/- 13y, between March and May 2020, out of 4200 HCW of a university hospital. Out of these 177, 93.8% worked in COVID-19 high-risk areas, 72.5% were nurses or assistants, 7.8% had asymptomatic infection and 6.7% suffered serious illness demanding inpatient care. Result(s): At T0, 73.5% HCW (144+ve/166) yielded over-cutoff anti-S sIgG (sIgGoc), mean (sIgGm) = 12.5 +/- 9.1 AU/mL, IS1 = 7.3%, IS2 = 84.9% and IS3 = 7.8%;at T1, sIgGoc = 48.2% (80+ve /166), sIgGm = 2.7 +/- 4.9 AU/mL, IS1 = 7.8%, IS2 = 86.2%, IS3 = 6.0%;at T2, sIgGoc = 25.4% (31+ve /122;late drop out:44), sIgGm = 1.3 +/- 2.8 AU/ mL, IS1 = 8.9%, IS2 = 81.3%, IS3 = 9.8%. So, a progressive decrease in mean serum neutralizing anti-S/ SARS-CoV- 2 IgG antibody concentrations was evident during the first six months after disease, in consonance with available data. Under cutoff concentrations were evident 6 weeks after infection in 26.5% of HCW, in 51.8% after 4 months and 74.6% after 6 months, approximately and even in over-cutoff measurements, values approached the threshold of positivity. Conclusion(s): These results suggest that post-infectious natural immunity against SARS-CoV- 2 is tendentially weak and fast waning, reinforcing the need to repeatedly boost recovered HCW. This measure, together with the collective protection measures and the use of adequate personal protective equipment, will maximize the protection for HCW and patients altogether.

Fractional order epidemiological model of SARS-CoV-2 dynamism involving Alzheimer's disease

In this paper, we study a Caputo-Fabrizio fractional order epidemiological model for the transmission dynamism of the severe acute respiratory syndrome coronavirus 2 pandemic and its relationship with Alzheimer's disease. Alzheimer's disease is incorporated into the model by evaluating its relevance to the quarantine strategy. We use functional techniques to demonstrate the proposed model stability under the Ulam-Hyres condition. The Adams-Bashforth method is used to determine the numerical solution for our proposed model. According to our numerical results, we notice that an increase in the quarantine parameter has minimal effect on the Alzheimer's disease compartment.Copyright © 2022 The Author(s)

Protection probability against SARS-CoV-2 Omicron variant BA.1, BA.2 and BA.5 in asympto- matic infection caused by prototype strain

Objective To estimate the protection probability against SARS-CoV-2 variant Omicron strains BA.1, BA.2 and BA.5 infection, symptomatic infection and severe disease outcomes in asymptomatic individuals infected with SARS-CoV-2 prototype strain previously. Methods Our previous study had shown that the dynamic change of neutralizing antibodies in asymptomatic individuals infected with the SARS-CoV-2 prototype strain. Based on our previous study, a peer–reviewed predictive model on the basis of logistic model was used to estimate the protection probability of asymptomatic individuals against Omicron strains BA.1, BA.2 and BA.5. We estimate the protection probability against infection, symptomatic infection and severe disease outcomes on 28, 51 and 261 days after confirmation. Results The protection probability against reinfection of Omicron variant strains BA.1, BA.2, and BA.5 on 28 days after confirmation were 30% (95% CI: 16%–52%) , 23% (95% CI: 15%–36%) and 8% (95% CI: 4%–16%) respectively, while decreased to 9% (95% CI: 3%–21%) , 6% (95% CI: 3%–12%) and 2% (95% CI: 1%–4%) on 261 days after confirmation. The protection probability against symptomatic infection of Omicron strains BA.1, BA.2, and BA.5 were 51% (95% CI: 28%–80%) , 42% (95% CI: 26%–67%) and 16% (95% CI: 7% – 40%) respectively on 28 days after confirmation, while decreased to 16% (95% CI: 7%–35%) , 12% (95% CI: 7% – 22%) and 3% (95% CI: 1% – 8%) on 261 days after confirmation. The protection probability against severe disease of Omicron strains BA.1, BA.2, and BA.5 were 91% (95% CI: 72%–98%) , 88% (95% CI: 70%–97%) and 66% (95% CI: 35%–90%) respectively on 28 days after confirmation, while decreased to 60% (95% CI: 35%–86%) , 51% (95% CI: 32%–75%) and 22% (95% CI: 10%–50%) on 261 days after confirmation. Conclusions Neutralizing antibodies induced in asymptomatic individuals infected with prototype strain could provide higher protection against Omicron strain BA.5 than Omicron strains BA.1 and BA.2. Among the three clinical outcomes, the protective probability against severe disease outcome was better, followed by symptomatic infection, and the protective probability against infection was poor. © 2023, Publication Centre of Anhui Medical University. All rights reserved.