Racism in pediatric health

SPECIAL REPORT Since the inception of the United States, social, economic, political, and scientific institutions have been built on a foundation emphasizing the inferiority of individuals related to phenotypic differences.1 This hierarchy ensconced white individuals as superior to all other groups with Native Americans and Blacks on the bottom. Some fifty years after the discovery of the genetic code, at a White House ceremony in 2000 to announce the discovery, Craig Venter, a pioneer of DNA sequencing, observed, "The concept of race has no genetic or scientific basis. With structural or institutional racism, there is decreased access to health care and resources for education, leading to lower health literacy and fewer health care providers of color.12'13 Over time, this has led to a distrust of the health care system as a whole by POC due to widely publicized historical events such as the Tuskegee Syphilis Study and the Marion tuberculosis outbreak. [...]non-Hispanic Blacks have a higher prevalence of recurrent asthma exacerbations and hospitalizations than Whites after adjusting for demographic and socioeconomic factors.16 One study revealed that with non-Black children, poor children were 45% more likely than children who were not poor to have asthma.

Rapid cytokine release assay in whole blood determines longitudinal T-cell responses against ancestral, Delta, and Omicron SARS CoV-2 variants

Background: A simple, accurate and rapid whole blood-based T-cell test was previously developed to determine SARS-CoV- 2- specific T-cell immunity. Herein, the test was utilized to measure the magnitude of T-cell responses up to 6 months post-vaccination, assess the effects of vaccine boosters, and to elucidate any effect that Delta and Omicron variants may have on T-cell immunity. Method(s): Immunocompetent individuals (n = 44) were recruited to donate a blood sample between one-and six-months post-vaccination. Whole blood was stimulated overnight with peptides spanning immunodominant regions specific for ancestral SARS-CoV- 2. Blood plasma samples were analysed for IL-2 production via Luminex xMAP cytokine array, as this was previously demonstrated to be the most accurate biomarker for the test. Following booster vaccinations, 58 individuals donated a blood sample between one-and four-months post-booster and T-cell responses after overnight stimulations were assessed. Additionally, 30 samples were stimulated with peptides from the immunodominant regions of the Delta and Omicron SARS-CoV- 2 variants and IL-2 levels were compared. Result(s): A comparison of T-cell responses from samples donated up to one-month and six-months post-vaccination revealed no significant differences in the magnitude of IL-2 production (p = 0.9252), with near equivalent means. Booster vaccinations increased the magnitude of the T-cell response in 69% of individuals analysed, with the mean production of IL-2 rising from 77pg/ml six-months pre-booster to 141pg/ml 3-weeks post-booster. Analysis of the longevity of post-booster T-cell response demonstrated no significant differences in the magnitude of IL-2 (p = 0.8141) production, with near equivalent means at one-month and 4-months post-booster (119pg/ml and 111pg/ml, respectively). Finally, no significant differences in the magnitude of IL-2 were observed between samples stimulated with either ancestral, Delta or Omicron peptides, with the means of each group being highly comparable. Conclusion(s): Results from this rapid whole blood-based T-cell test indicate that T-cell immunity to multiple variants of SARS-CoV- 2 within immunocompetent cohorts does not wane significantly over time. However, booster vaccinations may be important for individuals who have lower levels of immunity following their first complete vaccination doses. This test could be a valuable tool in the assessment of SARS-CoV- 2 immunity in multiple cohorts of clinical vulnerable individuals.

COVID-19 international experience in paediatric patients with congenital heart disease.

OBJECTIVE: As COVID-19 continues to affect the global population, it is crucial to study the impact of the disease in vulnerable populations. This study of a diverse, international cohort aims to provide timely, experiential data on the course of disease in paediatric patients with congenital heart disease (CHD). METHODS: Data were collected by capitalising on two pre-existing CHD registries, the International Quality Improvement Collaborative for Congenital Heart Disease: Improving Care in Low- and Middle-Income Countries and the Congenital Cardiac Catheterization Project on Outcomes. 35 participating sites reported data for all patients under 18 years of age with diagnosed CHD and known COVID-19 illness during 2020 identified at their institution. Patients were classified as low, moderate or high risk for moderate or severe COVID-19 illness based on patient anatomy, physiology and genetic syndrome using current published guidelines. Association of risk factors with hospitalisation and intensive care unit (ICU) level care were assessed. RESULTS: The study included 339 COVID-19 cases in paediatric patients with CHD from 35 sites worldwide. Of these cases, 84 patients (25%) required hospitalisation, and 40 (12%) required ICU care. Age <1 year, recent cardiac intervention, anatomical complexity, clinical cardiac status and overall risk were all significantly associated with need for hospitalisation and ICU admission. A multivariable model for ICU admission including clinical cardiac status and recent cardiac intervention produced a c-statistic of 0.86. CONCLUSIONS: These observational data suggest risk factors for hospitalisation related to COVID-19 in paediatric CHD include age, lower functional cardiac status and recent cardiac interventions. There is a need for further data to identify factors relevant to the care of patients with CHD who contract COVID-19 illness.

How will mass-vaccination change COVID-19 lockdown requirements in Australia?

Background To prevent future outbreaks of COVID-19, Australia is pursuing a mass-vaccination approach in which a targeted group of the population comprising healthcare workers, aged-care residents and other individuals at increased risk of exposure will receive a highly effective priority vaccine. The rest of the population will instead have access to a less effective vaccine. Methods We apply a large-scale agent-based model of COVID-19 in Australia to investigate the possible implications of this hybrid approach to mass-vaccination. The model is calibrated to recent epidemiological and demographic data available in Australia, and accounts for several components of vaccine efficacy. Findings Within a feasible range of vaccine efficacy values, our model supports the assertion that complete herd immunity due to vaccination is not likely in the Australian context. For realistic scenarios in which herd immunity is not achieved, we simulate the effects of mass-vaccination on epidemic growth rate, and investigate the requirements of lockdown measures applied to curb subsequent outbreaks. In our simulations, Australia's vaccination strategy can feasibly reduce required lockdown intensity and initial epidemic growth rate by 43% and 52%, respectively. The severity of epidemics, as measured by the peak number of daily new cases, decreases by up to two orders of magnitude under plausible mass-vaccination and lockdown strategies. Interpretation The study presents a strong argument for a large-scale vaccination campaign in Australia, which would substantially reduce both the intensity of future outbreaks and the stringency of non-pharmaceutical interventions required for their suppression. Funding Australian Research Council; National Health and Medical Research Council.

Circumventing anti-vector immunity towards adenoviral vectored vaccines

Replication deficient (RD) adenoviruses (Ad) are the most widely administered viral vectors, with licensed SARS-CoV-2 vaccines using vectors derived from human Ad type 5 (Ad5) and 26 (Ad26), and chimpanzee Ad ''ChAdOx1''. Ad vectored vaccines generate robust cellular and humoral immunity, against both the transgene-encoded protein and the Ad vector itself. It's unclear how many times a single Ad vector can be readministered before this anti-vector immunity impairs generation of the desired transgene-specific adaptive responses. Antivector immunity also arises from naturally acquired Ad infections. In the absence of anti-Ad5 immunity, Ad5 is a goldstandard vector with robust vaccine immunogenicity, however widespread Ad5 seroprevalence hampers its use as a vector for the global population. We developed novel pseudotyped Ads as RD vectored vaccines encoding SARS-CoV-2 spike protein. These vectors exhibit fiber knob swaps from low seroprevalence Ads grafted onto an Ad5 backbone. We characterised innate immune responses following administration of these vectors in mice, and spikespecific adaptive responses three weeks later. Furthermore, we quantified the effects of anti-vector humoral immunity against these vectors in an in vitro transduction assay using human plasma. The pseudotyped vectors exhibit many desirable vaccine characteristics as the equivalent Ad5 vector, including CD4+ and CD8+ T cell responses against multiple spike epitopes. Importantly, fiber knob pseudotyping can substantially circumvent the direct, humoral, anti-vector immunity induced through Ad exposure in humans. These data indicate the fiber knob plays an important role in anti-vector immunity, and can be manipulated for evasion of such responses without hampering vaccine immunogenicity.

BOOST KIDNEY: A Randomized Controlled Trial of Third Dose BNT162b2 vs. mRNA-1273 COVID-19 Vaccination in CKD and Dialysis Patients

Background: Due to waning humoral immunity, a third COVID-19 vaccine dose is recommended but there is a lack of evidence regarding whether there is benefit to homologous versus heterologous mRNA vaccination. Method(s): This was a multi-centre parallel group randomized controlled trial in Toronto, Ontario from September 30, 2021 to May 13, 2022 which enrolled participants with stage 3B-5 chronic kidney disease with prior homologous mRNA two dose vaccination. Overall 273 participants were randomized 1:1 to either 30mug BNT162b2 (n=137) or 100 mug mRNA-1273 (n=136) third dose stratified by initial vaccine type. Neutralizing antibodies against the B.1.1.529 (Omicron) variant of concern as well as binding SARS-CoV-2 IgG antibodies to the spike protein, receptor binding domain, and nucleocapsid protein were measured. Result(s): Participants had a median age of 67 years, 94% were on dialysis, 3% had prior COVID-19, and 59% had received BNT162b2 for initial two dose vaccination. Prior to the third vaccine dose, detectable Omicron neutralizing antibodies were present in 2% with BNT162b2 and 54% with mRNA-1273 two dose vaccination. At 1 month post third dose, among those with baseline BNT162b2, Omicron-specific neutralizing antibodies were detectable in 84% with third dose BNT162b2 in comparison to 83% with third dose mRNA-1273 (p=0.70). In those with baseline mRNA-1273, 100% receiving third dose mRNA-1273 had Omicron-specific neutralizing antibodies in comparison to 96% with third dose BNT162b2 (p=0.75). During the study period, 9.3% of participants (n=25) contracted COVID-19 and two died from COVID-19 with no difference in infection based on vaccine type (p=0.26). Conclusion(s): In this randomized controlled trial of third dose COVID-19 vaccination, both homologous and heterologous vaccination elicited robust SARS-CoV-2 neutralizing antibody response. (Figure Presented).

Humoral Responses in the Omicron Era Following a Three-Dose SARS-CoV-2 Vaccine Series in Kidney Transplant Recipients

Background: Kidney transplant recipients (KTR) have a diminished response to SARS-CoV-2 vaccination in comparison to immunocompetent individuals. Deeper understanding of the antibody response in KTRs following third-dose vaccination would enable identification of those who remain unprotected against Omicron and require additional treatment strategies. Method(s): We profiled antibody responses in KTRs pre-and at one and three months post-third-dose SARS-CoV2 mRNA-based vaccine. Anti-spike and anti-RBD IgG levels were determined by ELISA. Neutralization against wild-type, Beta, Delta and Omicron (BA.1) variants was determined using a SARS-CoV-2 spike pseudotyped lentivirus assay. Result(s): 44 KTRs were analysed at 1 and 3 months (n=26) post-third-dose. At one month, the proportion of participants with a robust antibody response had increased significantly from baseline, but Omicron-specific neutralizing antibodies were detected in just 45% of KTRs. Median anti-spike and anti-RBD antibody levels declined at 3 months, but the proportion of KTRs with a robust antibody response was unchanged. 38.5% KTRs maintained Omicron-specific neutralization at 3 months. No clinical variables were significantly associated with detectable Omicron neutralizing antibodies, but anti-RBD titres appeared to identify those with Omicron-specific neutralizing capacity. Conclusion(s): Over 50% of KTRs lack an Omicron-specific neutralization response 1 month following a third mRNA-vaccine dose. Among responders, binding and neutralizing antibody responses were well preserved at 3 months. Anti-RBD antibody titres may be a useful identifier of patients with detectable Omicron neutralizing antibody response.

Is COVID-19 Infection Associated With the Progression of Kidney Disease? Findings From a Population Based Observational Study From British Columbia, Canada

Background: Recent research suggests that COVID-19 infection is associated with acute kidney injury (AKI). Together the inflammation caused by the virus in the kidneys and the episodes of AKIs are risk factors for progression of kidney diseases. We investigated the risk of progression to kidney failure among chronic kidney disease (CKD) patients from BC, Canada who were infected with COVID-19. Method(s): In this retrospective cohort study, we analyzed a cohort of 22,188 nondialysis CKD patients aged >=18 years, with no prior history of ESKD and COVID-19 infection before the cohort entry date between January 27, 2020 & December 15, 2021. The cohort was derived from Patient Records and Outcome Management Information System (PROMIS), a population based integrated registry database for CKD patients under the nephrologist care in BC. Incident COVID-19 cases were iteratively matched without replacement to non-COVID-19 controls (1:3 ratio) based on age, sex, region of residency, diabetes status, eGFR and urine ACR, CKD vintage and COVID-19 vaccination status as of COVID-19 diagnosis date. The primary outcome was a composite of initiation of maintenance dialysis defined by dialysis performed for >=4 weeks, a sustained decline in eGFR defined by >=40% decline from baseline that sustained over >=4 weeks or incident kidney transplantation. Estimated HR and 95% CI using Fine and Gray subdistribution hazard model to account for death as a competing risk. Result(s): The analytic data included 1,708 patients, 475 (28%) COVID-19 cases and 1,233 (72%) non-COVID-19 controls. Median age was 71 years, 53% was male. Median follow-up was 8.3 months, 70 (4.10%) patients progressed to kidney failure. Among the non-dialysis CKD patients, the risk of developing kidney failure in COVID-19 infected cases was 24% higher compared to matched, non-COVID-19 infected controls. The HR (95% CI) was 1.24 (0.75, 2.06) (p-value: 0.39). Conclusion(s): COVID-19 infection in non-dialysis CKD patients appeared to be associated with higher risk of progression to kidney failure. Although not statistically significant, the substantial increase in risk estimate warrants close monitoring of kidney function among CKD patients after COVID-19 infection.

Changes in Practice/Outcomes of Pediatric/Congenital Catheterization in Response to the First Wave of COVID.

Background: The Coronavirus disease 2019 (COVID-19) pandemic has posed tremendous stress on the health care system. Its effects on pediatric/congenital catheterization program practice and performance have not been described. Objectives: To evaluate how case volumes, risk-profile, and outcomes of pediatric/congenital catheterization procedures changed in response to the first wave of COVID-19 and after that wave. Methods: A multicenter retrospective observational study was performed using Congenital Cardiac Catheterization Project on Outcomes Registry (C3PO) data to study changes in volume, case mix, and outcomes (high-severity adverse events [HSAEs]) during the first wave of COVID (March 1, 2020, to May 31, 2020) in comparison to the period prior to (January 1, 2019, to February 28, 2020) and after (June 1, 2020, to December 31, 2020) the first wave. Multivariable analyses adjusting for case type, hemodynamic vulnerability, and age group were performed. Hospital responses to the first wave were captured with an electronic study instrument. Results: During the study period, 12,557 cases were performed at 14 C3PO hospitals (with 8% performed during the first wave of COVID and 32% in the postperiod). Center case volumes decreased from a median 32.1 cases/mo (interquartile range: 20.7-49.0) before COVID to 22 cases/mo (interquartile range: 13-31) during the first wave (P = 0.001). The proportion of cases with risk factors for HSAE increased during the first wave, specifically proportions of infants and neonates (P < 0.001) and subjects with renal insufficiency (P = 0.02), recent cardiac surgery (P < 0.001), and a higher hemodynamic vulnerability score (P = 0.02). The observed HSAE risk did not change significantly (P = 0.13). In multivariable analyses, odds of HSAE during the first wave of COVID (odds ratio: 0.75) appeared to be lower than that before COVID, but the difference was not significant (P = 0.09). Conclusion: Despite increased case-mix complexity, C3PO programs maintained, if not improved, their performance in terms of HSAE. Exploratory analyses of practice changes may inform future harm-reduction efforts.

A framework for considering the utility of models when facing tough decisions in public health: a guideline for policy-makers.

The COVID-19 pandemic has brought the combined disciplines of public health, infectious disease and policy modelling squarely into the spotlight. Never before have decisions regarding public health measures and their impacts been such a topic of international deliberation, from the level of individuals and communities through to global leaders. Nor have models-developed at rapid pace and often in the absence of complete information-ever been so central to the decision-making process. However, after nearly 3 years of experience with modelling, policy-makers need to be more confident about which models will be most helpful to support them when taking public health decisions, and modellers need to better understand the factors that will lead to successful model adoption and utilization. We present a three-stage framework for achieving these ends.

Student Perceptions and Use of Social Media as Residency Program Information.

BACKGROUND AND OBJECTIVES: Virtual residency interviews during the 2020 COVID-19 pandemic posed unique challenges to students and residency programs in the United States. We evaluated fourth-year medical students' perceptions of the virtual format and social media use to help select residency programs. We also assessed applicant utilization and perceived usefulness of our social media content. METHODS: We administered an anonymous, web-based survey study of interviewees at an urban, academic medical center residency program. We analyzed data using descriptive statistics. RESULTS: Seventy-five of 138 applicants completed the survey (response rate 54%). Most applicants reported worry about obtaining enough information about residency programs to apply (64%) and to rank programs (87%). Though more traditional information sources remain most prevalent, social media is now widely used to research residency programs (62%). CONCLUSIONS: Most applicants to this family medicine residency program used social media to gather information, but they expressed worry that it was enough. Virtual interviews are likely to remain postpandemic, creating challenges for residency programs and especially for their hopeful applicants. Programs seeking to provide well-rounded information for applicants should maintain a social media presence as part of their recruitment practices.

Simulating Transmission Scenarios of the Delta Variant of SARS-CoV-2 in Australia.

An outbreak of the Delta (B.1.617.2) variant of SARS-CoV-2 that began around mid-June 2021 in Sydney, Australia, quickly developed into a nation-wide epidemic. The ongoing epidemic is of major concern as the Delta variant is more infectious than previous variants that circulated in Australia in 2020. Using a re-calibrated agent-based model, we explored a feasible range of non-pharmaceutical interventions, including case isolation, home quarantine, school closures, and stay-at-home restrictions (i.e., "social distancing.") Our modelling indicated that the levels of reduced interactions in workplaces and across communities attained in Sydney and other parts of the nation were inadequate for controlling the outbreak. A counter-factual analysis suggested that if 70% of the population followed tight stay-at-home restrictions, then at least 45 days would have been needed for new daily cases to fall from their peak to below ten per day. Our model predicted that, under a progressive vaccination rollout, if 40-50% of the Australian population follow stay-at-home restrictions, the incidence will peak by mid-October 2021: the peak in incidence across the nation was indeed observed in mid-October. We also quantified an expected burden on the healthcare system and potential fatalities across Australia.

Who Will Watch the Watchmen? The Ethico-political Arrangements of Algorithmic Proctoring for Academic Integrity

Critics of artificial intelligence have suggested that the principles of fairness, accountability and transparency (FATE) have been used for ‘ethics washing’, in order to appease industrial interests. In this article, we develop this relational and context-dependent analysis, arguing that ethics should not be understood as values or design decisions, but as socio-technical achievements, enacted in the practices of students, teachers and corporations. We propose that the ethics of using AI in education are political, involving the distribution of power, privilege and resources. To illustrate this, we trace the controversies that followed from an incident in which a student was misclassified as a cheat by an online proctoring platform during the Covid-19 lockdown, analysing this incident to reveal the socio-technical arrangements of academic integrity. We then show how Joan Tronto’s work on the ethics of care can help think about the politics of these socio-technical arrangements — that is, about historically constituted power relations and the delegation of responsibilities within these institutions. The paper concludes by setting the immediate need for restorative justice against the slower temporality of systemic failure, and inviting speculation that could create new relationships between universities, students, businesses, algorithms and the idea of academic integrity. © 2021, The Author(s).

104 The new virtual reality of CF care: Lessons learned in setting up a remote sampling service

Background: Regular microbiological sampling via cough swab or sputum collection is vital in CF care to detect early infection and implement timely optimal treatment [1]. Our service identifies on average 34 new Pseudomonas aeruginosa growths per year. Prior to the COVID-19 pandemic samples were performed routinely in pediatric CF outpatient clinic every 2-3 months by health care professionals and more frequently during pulmonary exacerbation;9 samples per patient per year on average. In March 2020 the UK went into its first lockdown, and 90% of our CF clinic appointments became virtual (video). A remote sampling service was rapidly implemented by the pediatric physiotherapy team. Methods: Sample packs with paid postage and compliant with Royal Mail regulations (UN3373) were sent out with written instructions. Parents wereaskedtotaketheirchild's sample, and avideo ofhowto complete and package the sample were provided. A physiotherapist was available virtually to guide the parent in sampling where necessary. Results: From July to December 2020, 640 sample packs were sent out to 340 children with CF in advance of their virtual clinic or following an urgent request. Only 588 (81.7%) specimens were returned, despite chasing late samples during the virtual clinic or sending reminders via text, required in approximately 25% of cases. Returned samples were received between 2 and 26 days of being taken. Conclusion: The postage delays experienced were concerning, not onlyas it increased the risk of the CF team missing the result, but also as Public Health England UK standards for microbiology investigations state that sputum should be processed promptly to reduce overgrowth with contaminants. Therefore, allresults received via post should be interpreted with caution, particularly if delayed [2]. The remote sample service was time-consuming, introduced a newcost to the service, and became harder to maintain as face-to-face services increased. However, as an urgent service improvement initiative it was successful as it picked up 35 new P. aeruginosa cases in 2020, which was in keeping with previous years' P. aeruginosa growths. This model has led to a more sustainable hospitalwide remote sampling service being established, now run by non-clinical teams. Remote sampling can now be requested electronically, saving time. Individualized QR codes are sent with the packs to be scanned by patients whenpostingthe specimen backThis informs the clinical teamso samples are not missed and can be actioned in a timely fashion.

Whole blood-based cytokine release assay identifies IL-2 as a biomarker for rapid determination of vaccine-induced SARS-CoV-2-specific T cell immune responses

Background: A simple, accurate and rapid whole blood-based T cell test was previously developed to determine SARS-CoV-2-specific T cell immunity. The test was established by comparing cytokine production from naturally infected convalescent donors with covid-19 negative donors. The data revealed IL-2 production to be the most indicative of prior SARS-CoV-2 infection. However, accurately identifying vaccine-induced SARS-CoV-2-specific T cell immunity via this method was still to be confirmed. Herein, we sort to address if this was possible. Method: A cohort of unvaccinated healthy individuals was recruited to donate a single blood sample for an overnight in vitro stimulation with peptides spanning immunodominant regions specific for SARS-CoV-2. Blood plasma samples were harvested and analysed for a broad panel of cytokines using ELISA for IFN-g and Luminex xMAP cytokine arrays for IL-2 and other TH1/TH2 cytokines. The same cohort were then asked to donate a second blood sample following SARS-CoV-2 vaccinations, and the same stimulations and analyses were performed. In addition, plasma anti-SARS-CoV-2 IgG levels were assessed in both pre-and post-vaccination samples by direct ELISA against the whole spike protein. Results: A multiplex cytokine array revealed IL-2 to be the most reliable biomarker in indicating a vaccine-induced SARS-CoV-2-specific T cell response, with 100% of post-vaccinated donors mounting a significant IL-2 response above a pre-determined cut off level for positivity of 19.91pg/ml. All donors demonstrated a considerable increase in magnitude of IL-2 responses from pre-vaccination to post-vaccination, with results ranging from ∼125% change to >36,000% change. In addition, IFN-g and plasma IgG ELISAs revealed both to be reliable biomarkers, with post-vaccination levels of each being significantly raised above pre-vaccination levels. However, the magnitude of these responses was not as greatly increased as those observed with IL-2, nor did they achieve an increase in 100% of donors assessed. Conclusion: This standardisable, rapid, and accurate T cell test approach can be utilised to make accurate and comparable assessments of vaccine-induced T cell immunity across multiple population cohorts. This could provide valuable insight into the extremely important question of how long vaccine-induced immunity may last, and aid decision making around if and when vaccine boosters should be administered.

Humoral response to the BNT162B2 vaccine in hemodialysis patients

Background: Hemodialysis (HD) patients have high mortality from COVID-19 and immunity following vaccination remains uncertain. This study evaluated SARS-CoV-2 antibody response in HD patients following BNT162b2 COVID-19 vaccination compared to health care workers (HCW) and convalescent serum. Methods: This single centre observational cohort study enrolled 142 HD patients and 35 HCW receiving the BNT162b2 vaccine. SARS-CoV-2 IgG antibodies to the spike protein (anti-spike), receptor binding domain (anti-RBD), and nucleocapsid protein (anti-NP) were measured in 66 HD patients receiving one vaccine dose, 76 HD patients receiving two vaccine doses, and 35 HCW receiving two vaccine doses. Results: In HD patients receiving a single BNT162b2 dose, seroconversion occurred in 53/66 (80%) for anti-spike and 35/66 (55%) for anti-RBD by 28 days post dose, but only 15/66 (23%) and 4/66 (6%), respectively attained a robust response defined as reaching the median level of anti-spike and anti-RBD in convalescent serum. In patients receiving two doses of BNT162b2 vaccine, seroconversion occurred in 69/72 (96%) for anti-spike and 63/72 (88%) for anti-RBD by 2 weeks following the second dose while 52/72 (72%) and 43/72 (60%) reached median convalescent serum levels of anti-spike and anti-RBD. In HCW, 35/35 (100%) exceeded median levels of anti-spike and anti-RBD in convalescent serum 2-4 weeks post second dose. Conclusions: This study found poor immunogenicity 28 days following a single dose of BNT162b2 vaccine in HD patients, supporting adherence to recommended vaccination schedules, and avoiding delay of the second dose in this population.

[National Health control in ports and airports of the Balearic Islands. SARS-CoV-2 Containment (March-June 2020).]

During the state of alert declared in the national territory in March 2020 due to the health crisis caused by SARS-CoV-2, the free movement of the population was restricted in order to prevent the spread of the virus. In the Balearic Islands, access by air and sea was limited and, in addition, health controls were established at the entry points of the islands aimed to detect people with COVID-19. The health check is understood as a Public Health surveillance procedure through which all persons authorised to travel at that time were tested. This procedure, together with the security measures to prevent the spread of the virus, had never before been implemented in the Balearic Islands and required the collaboration of various organizations in order to organise and execute it. This paper shares the experience and analysis of the health control measures implemented in these circumstances. To do so, it describes the procedure carried out, the devices that were developed, the main results and the assessment of the project as a whole. Finally, the positive aspects and possible improvements are considered. The most of people screened upon arrival in Balearics Islands did not register or show clinical symptoms of COVID-19.

How will mass-vaccination change COVID-19 lockdown requirements in Australia? (preprint)

Background: To prevent future outbreaks of COVID-19, Australia is pursuing a mass-vaccination approach in which a targeted group of the population comprising healthcare workers, aged-care residents and other individuals at increased risk of exposure will receive a highly effective priority vaccine. The rest of the population will instead have access to a less effective vaccine. Methods: We apply a large-scale agent-based model of COVID-19 in Australia to investigate the possible implications of this hybrid approach to mass-vaccination. The model is calibrated to recent epidemiological and demographic data available in Australia, and accounts for several components of vaccine efficacy. Findings: Within a feasible range of vaccine efficacy values, our model supports the assertion that complete herd immunity due to vaccination is not likely in the Australian context. For realistic scenarios in which herd immunity is not achieved, we simulate the effects of mass-vaccination on epidemic growth rate, and investigate the requirements of lockdown measures applied to curb subsequent outbreaks. In our simulations, Australia's vaccination strategy can feasibly reduce required lockdown intensity and initial epidemic growth rate by 43% and 52%, respectively. The severity of epidemics, as measured by the peak number of daily new cases, decreases by up to two orders of magnitude under plausible mass-vaccination and lockdown strategies. Interpretation: The study presents a strong argument for a large-scale vaccination campaign in Australia, which would substantially reduce both the intensity of future outbreaks and the stringency of non-pharmaceutical interventions required for their suppression.

Modelling transmission and control of the COVID-19 pandemic in Australia.

There is a continuing debate on relative benefits of various mitigation and suppression strategies aimed to control the spread of COVID-19. Here we report the results of agent-based modelling using a fine-grained computational simulation of the ongoing COVID-19 pandemic in Australia. This model is calibrated to match key characteristics of COVID-19 transmission. An important calibration outcome is the age-dependent fraction of symptomatic cases, with this fraction for children found to be one-fifth of such fraction for adults. We apply the model to compare several intervention strategies, including restrictions on international air travel, case isolation, home quarantine, social distancing with varying levels of compliance, and school closures. School closures are not found to bring decisive benefits unless coupled with high level of social distancing compliance. We report several trade-offs, and an important transition across the levels of social distancing compliance, in the range between 70% and 80% levels, with compliance at the 90% level found to control the disease within 13-14 weeks, when coupled with effective case isolation and international travel restrictions.