Letter to the Editor: A comparison of post-COVID vaccine myocarditis classification using the Brighton Collaboration criteria versus (United States) Centers for Disease Control criteria: an update

Abstract

(No abstract provided).

Audiovestibular adverse events following COVID-19 vaccinations

INTRODUCTION

Evidence regarding audiovestibular adverse events post COVID-19 vaccination to date has been inconclusive regarding a potential association. This study aimed to determine if there was an increase in audiovestibular events following COVID-19 vaccination in South-eastern Australia during January 2021-March 2023.

METHODS

A multi-data source approach was applied. First, a retrospective observational analysis of spontaneous reports of audiovestibular events to a statewide vaccine safety surveillance service, SAEFVIC. Second, a self-controlled case series analysis using general practice data collected via the POpulation Level Analysis and Reporting (POLAR) tool.

RESULTS AND CONCLUSIONS

This study is the first to demonstrate an increase in general practice presentations of vertigo following mRNA vaccines (RI = 1.40, P <.001), and tinnitus following both the Vaxzevria® adenovirus vector and mRNA vaccines (RI = 2.25, P <.001 and 1.53, P <.001 respectively). There was no increase in hearing loss following any COVID-19 vaccinations. Our study, however, was unable to account for the potential of concurrent COVID-19 infections, which literature has indicated to be associated with audiovestibular events. Healthcare providers and vaccinees should be alert to potential audiovestibular complaints after COVID-19 vaccination. Our analysis highlights the importance of using large real-world datasets to gather reliable evidence for public health decision making.

Emergency department presentations for chest complaints after mRNA COVID-19 vaccinations in children and adolescents

OBJECTIVE

To investigate characteristics and management of children presenting with chest complaints to a tertiary paediatric ED post-mRNA COVID-19 vaccine.

METHODS

This was a retrospective medical record review with data linkage to the Australian Immunisation Register. The study setting was the Royal Children's Hospital, Melbourne, Australia. Children <18 years who had a troponin blood test performed in hospital within 14 days of receiving mRNA COVID-19 vaccination were included. Elevated troponin and myocarditis or pericarditis as per Brighton criteria was the primary outcome. Vaccination status, length of stay, investigations and clinical management were secondary outcomes.

RESULTS

Six hundred and ten patients had a troponin test in 13 months. After exclusion of trauma-related tests (n = 31), known cardiac patients (n = 75) and others (n = 145), 359 troponins were obtained due to chest complaints and related symptoms, with 283 troponins assessed to be mRNA vaccination-related. There was a temporal peak in presentations with a 30-fold monthly increase in troponin post-commencement of mRNA COVID-19 vaccines. In those with chest complaints following mRNA vaccination, mean age was 14 years and 50.4% were female. Fourteen out of 283 (5%) vaccine-related troponins were abnormal with 14 patients assessed to have vaccine-associated myocarditis. No patients had pericarditis.

CONCLUSIONS

There was a large number of possible mRNA COVID-19 vaccine-related chest complaints presenting to the ED. Few patients had abnormal troponins or myocarditis.

Long term follow up and outcomes of Covid-19 vaccine associated myocarditis in Victoria, Australia: A clinical surveillance study

BACKGROUND

Myocarditis and myopericarditis are well described adverse events of special interest (AESI) following COVID-19 vaccinations. Although reports are reassuring regarding initial clinical outcomes, information about longer term outcomes remains limited. We aimed to further this knowledge and report outcomes to 6 months post diagnosis from a single population cohort.

METHODS

Reports of myocarditis following COVID-19 vaccination were followed up by SAEFVIC (Surveillance of Adverse Events Following Vaccination in the Community), the state-wide vaccine safety service for Victoria, Australia. Confirmed myocarditis cases (Brighton Collaboration Criteria levels 1-3) were followed up via surveys at 1, 3 and 6 months post symptom onset. Responses received between 22 February 2021 and 30 September 2022 were analysed.

RESULTS

87.5 % (N = 182) of eligible participants completed at least 1 survey report. 377 reports were analysed. 76.9 % of completed reports were from male patients. The median age of patients was 21 years [IQR: 16 to 32]. 54.8 % (n = 74) of survey reports at 6 months, reported ongoing symptoms. At all follow-up time points, females were significantly more likely to have ongoing symptoms. At 6 months, 51.9 % of male respondents reported symptom resolution compared to 22.6 % of female patients (p = 0.002). Females were also more likely to continue medication and have ongoing exercise restrictions. However, males were significantly more likely to have higher initial peak troponin results and abnormal initial cardiac imaging investigations.

CONCLUSIONS

There appears to be a significant proportion of patients who experience ongoing symptoms to 6 months post onset amongst patients that experience these AESI. Male patients were more likely to report earlier and more complete symptom recovery, despite significantly higher average initial peak troponin. This difference in phenotypic presentation in females compared to males warrants further investigation and there is a need for longer term follow up data.

Analyzing an immunization resource website: User browsing trends

PURPOSE

Access to internet-based resources may help to improve population health awareness and literacy surrounding immunization related topics. The primary aim of this study was to evaluate and analyze trends for a single immunization resource website, the Melbourne Vaccine Education Centre (MVEC).

PRINCIPAL RESULTS

Over a four-year period from 2019 to 2022, the website had over 2 million visitors from 236 countries. Users were predominantly female, in the 25 to 44 year age bracket and accessed resources using a mobile device. There was significant interest in specific vaccine related topics, particularly during the COVID-19 pandemic, that corresponded with key vaccine related recommendations and updates from a national level. Usage patterns saw spikes in interest around topics including COVID-19 vaccine administration techniques and adverse events following immunization.

MAJOR CONCLUSIONS

Use of online platforms including websites such as MVEC may reflect trends and behaviors towards immunization related information. Analysis of usage patterns have provided user insights into key domains of interest including areas such as vaccine administration, policies and programs, vaccine safety and barriers to vaccine uptake.

Increase in invasive group A streptococcal disease among Australian children coinciding with northern hemisphere surges

Background

Increases in invasive group A streptococcal disease (iGAS) have recently been reported in multiple countries in the northern hemisphere, occurring during, and outside of, typical spring peaks. We report the epidemiology of iGAS among children in Australia from 1 July 2018 to 31 December 2022.

Methods

The Paediatric Active Enhanced Disease Surveillance (PAEDS) Network prospectively collected iGAS patient notifications for children and young people aged less than 18 years admitted to five major Australian paediatric hospitals in Victoria, Queensland, Western Australia and the Northern Territory. Patients were eligible for inclusion if they had GAS isolated from a normally sterile body site, or met clinical criteria for streptococcal toxic shock syndrome or necrotising fasciitis with GAS isolated from a non-sterile site. We report patients' clinical and demographic characteristics, and estimate minimum incidence rates.

Findings

We identified 280 paediatric iGAS patients, median age 4.5 years (interquartile range 1.4-6.4). We observed a pre-pandemic peak annualised incidence of 3.7 per 100,000 (95% CI 3.1-4.4) in the 3rd quarter of 2018, followed by a decline to less than 1.0 per 100,000 per quarter from 2020 to mid-2021. The annualised incidence increased sharply from mid-2022, peaking at 5.2 per 100,000 (95% CI 4.4-6.0) in the 3rd quarter and persisting into the 4th quarter (4.9 per 100,000, 95% CI 4.2-5.7). There were 3 attributable deaths and 84 (32%) patients had severe disease (overall case fatality rate 1%, 95% CI 0.2-3.3). Respiratory virus co-infection, positive in 57 of 119 patients tested, was associated with severe disease (RR 1.9, 95% CI 1.2-3.0). The most common emm-type was emm-1 (60 of 163 isolates that underwent emm-typing, 37%), followed by emm-12 (18%).

Interpretation

Australia experienced an increase in the incidence of iGAS among children and young people in 2022 compared to pandemic years 2020-2021. This is similar to northern hemisphere observations, despite differences in seasons and circulating respiratory viruses. Outbreaks of iGAS continue to occur widely. This emphasises the unmet need for a vaccine to prevent significant morbidity associated with iGAS disease.

Funding

Murdoch Children's Research Institute funded open access publishing of this manuscript.

The clinicopathological features of thrombosis with thrombocytopenia syndrome following ChAdOx1-S (AZD1222) vaccination and case outcomes in Australia: a population-based study

Background

Thrombosis with thrombocytopenia syndrome (TTS) associated with viral vector COVID-19 vaccines, including ChAdOx1-S (AstraZeneca AZD1222) vaccine, can result in significant morbidity and mortality. We report the clinicopathological features of TTS following ChAdOx1-S vaccination and summarise the case outcomes in Australia.

Methods

In this cohort study, patients diagnosed with TTS in Australia between 23 March and 31 December 2021 were identified according to predefined criteria. Cases were included if they met the Therapeutic Goods Administration (TGA) probable and confirmed case definitions and were reclassified using Centres for Disease Control and Prevention (CDC) definition for analysis. Data were collected on patient baseline characteristics, clinicopathological features, risk factors, treatment and outcomes.

Findings

A total of 170 TTS cases were identified, with most occurring after the first dose (87%) of ChAdOx1-S. The median time to symptom onset after vaccination and symptom onset to admission was 11 and 2 days respectively. The median age of cases was 66 years (interquartile range 55-74). All except two patients received therapeutic anticoagulation and 66% received intravenous immunoglobulin. Overall, 85.3% of cases were discharged home after a median hospitalisation of 6 days, 9.4% required ongoing rehabilitation and 5.3% died. Eight deaths were related to TTS, with another dying from an unrelated condition while receiving treatment for TTS. Deaths occurred more commonly in those classified as Tier 1 according to the CDC definition and were associated with more severe thrombocytopenia and disease-related haemorrhage.

Interpretation

TTS, while rare, can be severe and have catastrophic outcomes in some individuals. In Australia, the mortality rate was low compared to that reported in other high-income countries. Almost all received therapeutic anticoagulation with no bleeding complications and were successfully discharged. This emphasises the importance of community education and an established pathway for early recognition, diagnosis and treatment of TTS.

Funding

Australian Commonwealth Department of Health and Aged Care. H.A Tran, N. Wood, J. Buttery, N.W. Crawford, S.D. Chunilal, V.M. Chen are supported by Medical Research Future Funds (MRFF) grant ID 2015305.

Safety of BCG vaccination and revaccination in healthcare workers

BCG vaccination and revaccination are increasingly being considered for the protection of adolescents and adults against tuberculosis and, more broadly, for the off-target protective immunological effects against other infectious and noninfectious diseases. Within an international randomized controlled trial of BCG vaccination in healthcare workers (the BRACE trial), we evaluated the incidence of local and serious adverse events, as well as the impact of previous BCG vaccination on local injection site reactions (BCG revaccination). Prospectively collected data from 99% (5351/5393) of participants in Australia, Brazil, Spain, The Netherlands and the UK was available for analysis. Most BCG recipients experienced the expected self-limiting local injection site reactions (pain, tenderness, erythema, swelling). BCG injection site itch was an additional common initial local symptom reported in 49% of BCG recipients. Compared to BCG vaccination in BCG-naïve individuals, BCG revaccination was associated with increased frequency of mild injection site reactions, as well as earlier onset and shorter duration of erythema and swelling, which were generally self-limiting. Injection site abscess and regional lymphadenopathy were the most common adverse events and had a benign course. Self-resolution occurred within a month in 80% of abscess cases and 100% of lymphadenopathy cases. At a time when BCG is being increasingly considered for its off-target effects, our findings indicate that BCG vaccination and revaccination have an acceptable safety profile in adults.

Considerations for vaccinating children against COVID-19

COVID-19 vaccines have been introduced in children and adolescents in many countries. However, high levels of community transmission and infection-derived immunity make the decision to introduce COVID-19 vaccination of children in countries yet to do so particularly challenging. For example, other vaccine preventable diseases, including measles and polio, generally have far higher childhood morbidity and mortality in low-income and middle-income countries (LMICs) than COVID-19, and coverage with these vaccines has declined during the pandemic. Many countries are yet to introduce pneumococcal conjugate and rotavirus vaccines for children, which prevent common causes of childhood death, or human papillomavirus vaccine for adolescents. The Pfizer and Moderna COVID-19 vaccines that have been widely tested in children and adolescents have a positive risk-benefit profile. However, the benefit is less compared with other life-saving vaccines in this age group, particularly in LMICs and settings with widespread infection-derived immunity. The resources required for rollout may also pose a considerable challenge in LMICs. In this paper, we describe COVID-19 in children, with a focus on LMICs, and summarise the published literature on safety, efficacy and effectiveness of COVID-19 vaccination in children and adolescents. We highlight the complexity of decision-making regarding COVID-19 vaccination of children now that most of this low-risk population benefit from infection-derived immunity. We emphasise that at-risk groups should be prioritised for COVID-19 vaccination; and that if COVID-19 vaccines are introduced for children, the opportunity should be taken to improve coverage of routine childhood vaccines and preventative healthcare. Additionally, we highlight the paucity of epidemiological data in LMICs, and that for future epidemics, measures need to be taken to ensure equitable access to safe and efficacious vaccines before exposure to infection.

Corrigendum to "Lower risk of multi-system Inflammatory Syndrome in Children (MIS-C) with the Omicron variant" [The Lancet Regional Health - Western Pacific 27 (2022) 100604]

[This corrects the article DOI: 10.1016/j.lanwpc.2022.100604.].

Erratum: Factors influencing scar formation following Bacille Calmette-Guérin (BCG) vaccination

[This corrects the article DOI: 10.1016/j.heliyon.2023.e15241.].

A novel anterior nasal swab to detect respiratory viruses: a prospective study of diagnostic accuracy

Detection of respiratory viruses requires testing of the upper respiratory tract to obtain specimens for analysis. However, nasal and throat swabs can cause discomfort and procedural anxiety in children. Respiratory sampling methods which are accurate and less invasive are needed. We aim to determine the positive and negative percentage agreement of a novel anterior nasal swab (ANS) compared with the combined throat and anterior nasal swab (CTN), the reference standard, for detection of respiratory viruses. Children 5 - 18 years of age presenting to a tertiary paediatric hospital with respiratory symptoms were tested with both swabs in randomised order. Respiratory samples were tested on a multiplex RT-PCR panel. Viral detections, RT-PCR cycle-threshold values and child/parent/clinician experience of the swab were recorded. There were 157 viral detections from 249 participant CTN swabs. In comparison with the CTN, the overall positive and negative percentage agreement of ANS for detection of respiratory viruses was 96.2% (95% CI, 91.8-98.3%) and 99.8% (95% CI, 99.6-99.9%), respectively. The ANS was "extremely comfortable", or only a "little uncomfortable" for 90% of children compared with 48% for CTN. 202 children (84%) rated the ANS as the preferred swab, and 208 (87%) indicated they would prefer ANS for future testing. The ANS required additional laboratory handling processes compared to the CTN. The ANS has high positive percentage agreement and is comparable to the current standard of care. The high acceptability from the less invasive ANS provides a more comfortable method for respiratory virus testing in children.Trial registrationClinicalTrials.gov ID NCT05043623.

COVID-19 related ICU admissions in paediatric and young adult patients in Australia: a national case series 2020-2022

Background

COVID-19 pandemic research efforts have focused on disease phenotypes in adults. A distinct spectrum of illness has been documented in paediatric populations. We aimed to review paediatric intensive care unit (ICU) admissions in Australia, across differing variant predominant phases of the pandemic.

Methods

Data reported to the Short PeRiod IncideNce sTudy of Severe Acute Respiratory Infection (SPRINT-SARI) Australia, across 49 ICUs from February 2020 to June 2022 were extracted. We defined 'child' as patients aged <12 years, 'adolescent' as patients aged 12-17 years, and 'young adult' as patients aged 18-25 years.

Findings

We identified 226 paediatric ICU admissions with COVID-19, representing 3.9% of ICU admissions across the study period. Comorbidity was present in 34.6% of children, 51.4% of adolescents, and 48.7% of young adults. The need for respiratory support was highest in young adults. While 28.3% of patients <18 years required invasive ventilation, in-hospital mortality in paediatric patients was 3.6%. During the Omicron period, there was an increase in the annualised incidence of age-specific COVID-19 ICU admissions per 100,000 population, albeit a decrease in the incidence per 1000 SARS-CoV-2 notifications.

Interpretation

This study demonstrated an appreciable burden of COVID-19 in paediatric patients. Adolescent patients presented phenotypically similar to young adults, however, illness severity was lower in younger cohorts. The Omicron phase of the pandemic demonstrated an increased age-specific population incidence of COVID-19 ICU admissions, albeit a reduced incidence when based on SARS-CoV-2 notifications.

Funding

SPRINT-SARI Australia is supported by the Department of Health, Commonwealth of Australia [Standing Deed SON60002733].

Factors influencing scar formation following Bacille Calmette-Guérin (BCG) vaccination

The prevalence of scar formation following Bacille Calmette-Guérin (BCG) vaccination varies globally. The beneficial off-target effects of BCG are proposed to be stronger amongst children who develop a BCG scar. Within an international randomised trial ('BCG vaccination to reduce the impact of coronavirus disease 2019 (COVID-19) in healthcare workers'; BRACE Trial), this nested prospective cohort study assessed the prevalence of and factors influencing scar formation, as well as participant perception of BCG scarring 12 months following vaccination . Amongst 3071 BCG-recipients, 2341 (76%) developed a BCG scar. Scar prevalence was lowest in Spain and highest in UK. Absence of post-injection wheal (OR 0.4, 95%CI 0.2-0.9), BCG revaccination (OR 1.7, 95%CI 1.3-2.0), female sex (OR 2.0, 95%CI 1.7-2.4), older age (OR 0.4, 95%CI 0.4-0.5) and study country (Brazil OR 1.6, 95%CI 1.3-2.0) influenced BCG scar prevalence. Of the 2341 participants with a BCG scar, 1806 (77%) did not mind having the scar. Participants more likely to not mind were those in Brazil, males and those with a prior BCG vaccination history. The majority (96%) did not regret having the vaccine. Both vaccination-related (amenable to optimisation) and individual-related factors affected BCG scar prevalence 12 months following BCG vaccination of adults, with implications for maximising the effectiveness of BCG vaccination.

Paediatric admissions with SARS-CoV-2 during the Delta and Omicron waves: an Australian single-centre retrospective study

BACKGROUND

The clinical course of Australian children admitted to hospital with COVID-19 infection is not well understood, particularly over the Omicron period.

METHODS

This study describes paediatric admissions to a single tertiary paediatric institution through the Delta and Omicron variant waves. All children admitted from 1 June 2021 to 30 September 2022 with a diagnosis of COVID-19 infection were included for analysis.

RESULTS

117 patients were admitted during the Delta wave compared with 737 during the Omicron wave. The median length of stay was 3.3 days (IQR 1.7-6.75.1) during Delta, compared with 2.1 days (IQR 1.1-4.53.4) during Omicron (p<0.01). 83 patients (9.7%) required intensive care unit (ICU) admission, a greater proportion during Delta (20, 17.1%) than Omicron (63, 8.6%, p<0.01). Patients admitted to the ICU were less likely to have received a dose of COVID-19 vaccination prior to admission than patients admitted to the ward (8, 24.2% vs 154, 45.8%, p=0.028).

CONCLUSION

The Omicron wave resulted in an absolute increase in the number of children compared with Delta, but cases had lower severity, demonstrated by shorter length of stay and a smaller proportion of patients requiring intensive care. This is consistent with US and UK data describing a similar pattern.

Stick with the nose…Saliva rapid antigen testing is not a viable method for testing children under 5 years old

AIM

Respiratory testing with rapid antigen tests (RATs) in children under 5 years of age may be uncomfortable and presents specific challenges to testing due to compliance and procedural distress. The aim of this study was to investigate sensitivity and feasibility of self-collected nasal and saliva RAT tests compared with a combined nose and throat (CTN) swab PCR in children under 5.

METHODS

Children aged between 1 month and 5 years, with confirmed COVID-19 or who were a household contact within 7 days were included. A saliva RAT, nasal RAT and CTN swab were collected by the parent. SARS-CoV-2 cycle threshold (Ct) values for CTN tested by PCR were compared with saliva and nasal RAT results. Parent preference for method of sample was recorded.

RESULTS

Forty-one children were recruited with median age of 1.5 (interquartile range 0.7-4.0) years. Only 22/41 (54%) of parents were able to successfully collect a saliva RAT from their child. Sensitivity of the nasal RAT and saliva RAT was 0.889 (95% confidence interval (CI) 0.739-0.969) and 0.158 (95% CI 0.034-0.396), respectively. Upper limit of nasal RAT detection by CTN Ct value was higher than saliva (36.05 vs. 27.29). While saliva RAT was rated most comfortable, nasal RAT was rated the preferred specimen by parents for future testing, due to saliva collection difficulties and time taken.

CONCLUSIONS

Rapid antigen testing with nasal RAT is a more feasible and sensitive method for SARS-CoV-2 detection in young children compared with saliva RAT.

Complications of Influenza A or B Virus Infection in Individuals With SCN1A-Positive Dravet Syndrome

BACKGROUND AND OBJECTIVES

To determine the frequency and spectrum of complications of influenza infection in individuals with SCN1A-positive Dravet syndrome (SCN1A-DS).

METHODS

Individuals with SCN1A-DS were identified in neurologists' care at 2 hospitals in Melbourne, Australia, with additional searches of EEG databases, the Victorian PAEDS FluCan influenza database, and the University of Melbourne Epilepsy Genetics Research Program database. Medical records were searched and families questioned to identify individuals who had an influenza infection; reported infections were confirmed by pathology report. For these individuals, we obtained baseline clinical characteristics and clinical details of the influenza infection.

RESULTS

Twenty-one of 82 individuals (26%) had 24 documented influenza infections (17 influenza A and 7 influenza B) at age 0.5-25 years (median 4 years). All presented to hospital, 18/24 (75%) for status epilepticus or seizure exacerbations. Recovery was prompt in 18/24 (75%) infections, delayed but complete in 1/24 (4%) and incomplete in 5/24 (21%). One child died from influenza pneumonia, and long-term neurologic sequelae were seen with 4 infections. These individuals were poorly responsive after termination of status epilepticus. Brain imaging in 2 showed cerebral edema and 1 also having imaging features of laminar necrosis. All have ongoing neurologic deficits compared with their baseline, 1 having profound global impairment.

DISCUSSION

Our data show that patients with SCN1A-DS are highly susceptible to neurologic complications during and severe sequelae after influenza infection, including moderate to severe persistent neurologic impairments and death. Safe administration of the seasonal influenza vaccine should be prioritized for this population.

Shoulder injury following COVID-19 vaccine administration: a case series and proposed diagnostic algorithm

BACKGROUND

Shoulder Injury Related to Vaccine Administration (SIRVA) is a preventable adverse event following incorrect vaccine administration, which can result in significant long-term morbidity. There has been a notable surge in reported cases of SIRVA as a rapid national population-based COVID-19 immunization program has been rolled out across Australia.

METHODS

Surveillance of Adverse Events Following Vaccination in the Community (SAEFVIC) in Victoria identified 221 suspected cases of SIRVA following the commencement of the COVID-19 vaccination program, reported between February 2021 and February 2022. This review describes the clinical features and outcomes of SIRVA in this population. Additionally, a suggested diagnostic algorithm is proposed, in order to facilitate early recognition and management of SIRVA.

RESULTS

151 cases were confirmed as SIRVA, with 49.0% having received vaccines at state vaccination centers. 75.5% were suspected incorrect administration site, with most patients experiencing shoulder pain and restricted movement within 24 hours of vaccination, lasting on average 3 months.

CONCLUSION

Improved awareness and education regarding SIRVA is imperative in a pandemic vaccine roll-out. The development of a structured framework for evaluating and managing suspected SIRVA will aid in timely diagnosis and treatment, essential to mitigate potential long-term complications.

Aiming too high: Shoulder injury related to vaccine administration (SIRVA): A case series

PURPOSE

Shoulder injury directly related to vaccination (SIRVA) occurs when a vaccine is administered too high in the shoulder. The primary aim of this study was to accurately detail the occurrence, symptoms, diagnosis, management and long-term outcomes of SIRVA cases in Victoria, Australia.

PRINCIPAL RESULTS

The study identified 102 SIRVA cases from 2007 to 2020 from the Surveillance of Adverse Events Following Vaccination in the Community (SAEFVIC) database. The majority [73/85; (86 %)] of cases resolved completely with a median time to resolution of 8 weeks and no statistically significant difference in recovery by immunisation provider type or baseline imaging.

MAJOR CONCLUSIONS

This large case series includes long-term clinical progress in SIRVA, allowing accurate evaluation and analysis. Further evaluation is required to establish if other risk factors contribute to SIRVA, which may help with targeted, tailored education for providers on correct vaccine administration technique, including in large and rapid vaccine rollouts.

Guillain-Barré syndrome temporally associated with COVID-19 vaccines in Victoria, Australia

Guillain-Barré syndrome (GBS) is an adverse event of special interest (AESI) for surveillance systems monitoring adverse events following immunisation (AEFI) with COVID-19 vaccines. Emerging data support a temporal association between GBS and adenovirus-vector COVID-19 vaccines. We present a case series of GBS reports submitted between February and November 2021 to our enhanced spontaneous surveillance system (SAEFVIC) in Victoria, Australia, following vaccination with either the adenovirus-vector vaccine Vaxzevria ChadOx1-S (AstraZeneca) or an mRNA vaccine (Comirnaty BNT162b2 [Pfizer-BioNTech] or Spikevax mRNA-1273 [Moderna]). For each report, Brighton Collaboration case definitions were used to describe diagnostic certainty. Severity was graded using the GBS Disability Score. The observed incidence of GBS following immunisation against COVID-19 was compared to expected background ICD10-AM G61.0 coded hospitalisations. There were 41 total cases of GBS reported to SAEFVIC following Vaxzevria (n = 38), Comirnaty (n = 3), or Spikevax (n = 0) vaccines. The observed GBS incidence rate exceeded the expected background rate for Vaxzevria only, with 1.85 reports per 100,000 doses following dose 1, higher than the expected rate of 0.39 hospital admissions per 100,000 adults within 42 days of vaccination. Of 38 GBS reports following Vaxzevria, the median age at vaccination was 66 years and median onset of symptoms was 14 days following immunisation. There was one death. Four cases initially categorised as GBS were later reclassified as acute-onset chronic inflammatory demyelinating polyneuropathy. Fatigue was the predominant persisting symptom reported at follow up. Additional global studies are required to characterise risk factors, clinical variability, and to provide precision and generalizability regarding AEFI risks such as GBS associated with different vaccine platforms, which will help inform communication of the potential benefits and risks of COVID19 vaccination.

Age-related differences in SARS-CoV-2 binding factors: An explanation for reduced susceptibility to severe COVID-19 among children?

CONTEXT

In contrast with other respiratory viruses, children infected with SARS-CoV-2 are largely spared from severe COVID-19.

OBJECTIVES

To critically assess age-related differences in three host proteins involved in SARS-CoV-2 cellular entry: angiotensin-converting enzyme 2 (ACE2), transmembrane serine protease 2 (TMPRSS2) and furin.

METHODS

We systematically searched Medline, Embase, and PubMed databases for relevant publications. Studies were eligible if they evaluated ACE2, TMPRSS2 or furin expression, methylation, or protein level in children.

RESULTS

Sixteen papers were included. Age-dependent differences in membrane-bound and soluble ACE2 were shown in several studies, with ACE2 expression increasing with age. TMPRSS2 and furin are key proteases involved in SARS-CoV-2 spike protein cleavage. TMPRSS2 expression is increased by circulating androgens and is thus low in pre-pubertal children. Furin has not currently been well researched.

LIMITATIONS

High levels of study heterogeneity.

CONCLUSIONS

Low expression of key host proteins may partially explain the reduced incidence of severe COVID-19 among children, although further research is needed.

Victorian Specialist Immunisation Services (VicSIS) - bolstering adult clinics for COVID-19 vaccines

The Victorian Specialist Immunization Services (VicSIS) was established in Victoria, Australia, in February 2021, aiming to enhance vaccine safety services for Coronavirus disease (COVID-19) vaccines. VicSIS supports practitioners and patients with complex vaccine safety questions, including those who experience adverse events following immunization (AEFI) after COVID-19 vaccines. VicSIS provides individual vaccination recommendations, allergy testing, vaccine challenges, and vaccination under supervision. VicSIS initially comprised of eight adult COVID-19 specialist vaccination clinics, subsequently, expanding to better support pediatric patients as the Australian vaccine roll-out extended to adolescents and children. Since their establishment to September 2021, the inaugural VicSIS clinics received a total of 26,401 referrals and reviewed 6,079 patients. Consults were initially predominantly for pre-vaccination reviews, later predominantly becoming post-vaccination AEFI reviews as the program progressed. Regardless of the type of consult, the most common consult outcome was a recommendation for routine vaccination (73% and 55% of consult outcomes respectively). VicSIS is an integral component of the COVID-19 vaccination program and supports confidence in COVID-19 vaccine safety by providing consistent advice across the state. VicSIS aims to strengthen the health system through the pandemic, bolstering specialist immunization services beyond COVID-19 vaccines, including training the next generation of vaccinology experts.

Vaccine safety in Australia during the COVID-19 pandemic: Lessons learned on the frontline

Surveillance of Adverse Events Following Vaccination in the Community (SAEFVIC), Victoria's vaccine safety service for reporting adverse events following immunisation (AEFI), has provided integrated spontaneous surveillance and clinical services for individuals affected by AEFI since 2007. We describe SAEFVIC's response to the COVID-19 vaccine program, and reflect on lessons learned for vaccine safety. The massive scale of the Australian COVID-19 vaccine program required rapid adaptations across all aspects of SAEFVIC's vaccine safety services. Collection of AEFI reports was streamlined and expanded, incorporating both spontaneous and active surveillance data. Dramatically increased report volumes were managed with additional staffing, and innovations to automate, filter, and triage reports for priority follow up. There were two major adverse events of special interest (AESI): thrombosis with thrombocytopaenia syndrome and myocarditis, with multiple other AESI also investigated. Rapid escalation mechanisms to respond to AESI were established, along with AESI-specific databases for enhanced monitoring. Vaccine education and training resources were developed and public-facing vaccine safety reports updated weekly. Frequent communication with local and national government and regulatory bodies, and consultation with specialist groups was essential. The COVID-19 vaccine program has highlighted the importance of vaccine safety in supporting public confidence in vaccines and informing evidence-based immunisation policy. Supporting the COVID-19 vaccine program has required flexibility in adapting to policy changes and evolving vaccine safety signals, careful triage and prioritisation, informatics innovation, and enhanced engagement with the public regarding vaccine safety. Long-term investment to continue strengthening vaccine safety systems, building on lessons learned, will be essential for the ongoing success of Australian vaccination programs.

Influenza vaccine administration in a paediatric intensive care unit

AIM

We describe the clinical profile of children and outcomes of influenza immunisation for patients in a paediatric intensive care unit (PICU).

METHODS

Over two influenza seasons: 19/04/2018 to 07/08/2018 and 02/05/2019 to 10/10/2019, an immunisation nurse and PICU nurse coordinator met weekly and identified patients to receive the influenza vaccine. An inpatient list of PICU patients was screened for eligible patients: greater than 6 months of age, did not have imminent procedures (e.g. surgery) or were not critically unwell, as determined by the treating team, to receive the influenza vaccine. Patients were excluded if they had undergone surgery in the previous 24 hours or were being treated palliatively.

RESULTS

Sixty patients in PICU were identified, with 43% (26/60) receiving the vaccine while in PICU and 17% (10/60) once discharged from PICU to the general ward environment. The majority of patients immunised were in PICU due to cardiac surgery/cardiology or general medical conditions, such as cerebral palsy or RSV bronchiolitis. There were no reported adverse events following immunisation.

CONCLUSIONS

We have demonstrated the suitability and acceptability of children in the PICU receiving the seasonal influenza vaccine and tailored interventions to follow-up once discharged from PICU to optimise protection.

COVID ‐19 in New South Wales children during 2021: severity and clinical spectrum

Objectives: To describe the severity and clinical spectrum of coronavirus disease 2019 (COVID‐19) in children during the 2021 New South Wales outbreak of the Delta variant of the severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2).

Design, setting: Prospective cohort study in three metropolitan Sydney local health districts, 1 June – 31 October 2021.

Participants: Children under 16 years of age with positive SARS‐CoV‐2 nucleic acid test results admitted to hospital or managed by the Sydney Children’s Hospital Network (SCHN) virtual care team.

Main outcome measures: Age‐specific SARS‐CoV‐2 infection frequency, overall and separately for SCHN virtual and hospital patients; rates of medical and social reason admissions, intensive care admissions, and paediatric inflammatory multisystem syndrome temporally associated with SARS‐CoV‐2 per 100 SARS‐CoV‐2 infections; demographic and clinical factors that influenced likelihood of hospital admission.

Results: A total of 17 474 SARS‐CoV‐2 infections in children under 16 were recorded in NSW, of whom 11 985 (68.6%) received SCHN‐coordinated care, including 459 admitted to SCHN hospitals: 165 for medical reasons (1.38 [95% CI, 1.17–1.59] per 100 infections), including 15 admitted to intensive care, and 294 (under 18 years of age) for social reasons (2.45 [95% CI, 2.18–2.73] per 100 infections). In an analysis that included all children admitted to hospital and a random sample of those managed by the virtual team, having another medical condition (adjusted odds ratio [aOR], 7.42; 95% CI, 3.08–19.3) was associated with increased likelihood of medical admission; in univariate analyses, non‐asthmatic chronic respiratory disease was associated with greater (OR, 9.21; 95% CI, 1.61–174) and asthma/viral induced wheeze with lower likelihood of admission (OR, 0.38; 95% CI, 0.18–0.78). The likelihood of admission for medical reasons declined from infancy to 5–11 years, but rose again for those aged 12–15 years. Sex and Indigenous status did not influence the likelihood of admission.

Conclusion: Most SARS‐CoV‐2 infections (Delta variant) in children were asymptomatic or associated with mild disease. Hospitalisation was relatively infrequent, and most common for infants, adolescents, and children with other medical conditions. More children were hospitalised for social than for medical reasons.

The known: Information regarding disease severity and reasons for hospital admissions of children with COVID‐19 in Australia is very limited.

The new: In 2021, more NSW children with SARS‐CoV‐2 infections were hospitalised for social or welfare reasons (294, 64%; 2.45 per 100 infections) than for medical treatment (165, 36%; 1.38 per 100 infections). Children under six months of age, aged 12–15 years, or with another medical condition were more likely to be hospitalised than other children.

The implications: As acute COVID‐19 is typically mild in children, measures that protect them from SARS‐CoV‐2 but harm their overall wellbeing may be disproportionate. Community support for children with special care needs could reduce the number of hospitalisations.

SARS-CoV-2-specific T cell memory with common TCRαβ motifs is established in unvaccinated children who seroconvert after infection

As the establishment of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-specific T cell memory in children remains largely unexplored, we recruited convalescent COVID-19 children and adults to define their circulating memory SARS-CoV-2-specific CD4+ and CD8+ T cells prior to vaccination. We analyzed epitope-specific T cells directly ex vivo using seven HLA class I and class II tetramers presenting SARS-CoV-2 epitopes, together with Spike-specific B cells. Unvaccinated children who seroconverted had comparable Spike-specific but lower ORF1a- and N-specific memory T cell responses compared with adults. This agreed with our TCR sequencing data showing reduced clonal expansion in children. A strong stem cell memory phenotype and common T cell receptor motifs were detected within tetramer-specific T cells in seroconverted children. Conversely, children who did not seroconvert had tetramer-specific T cells of predominantly naive phenotypes and diverse TCRαβ repertoires. Our study demonstrates the generation of SARS-CoV-2-specific T cell memory with common TCRαβ motifs in unvaccinated seroconverted children after their first virus encounter.

Virology and immune dynamics reveal high household transmission of ancestral SARS-CoV-2 strain

BACKGROUND

Household studies are crucial for understanding the transmission of SARS-CoV-2 infection, which may be underestimated from PCR testing of respiratory samples alone. We aim to combine the assessment of household mitigation measures; nasopharyngeal, saliva, and stool PCR testing; along with mucosal and systemic SARS-CoV-2-specific antibodies, to comprehensively characterize SARS-CoV-2 infection and transmission in households.

METHODS

Between March and September 2020, we obtained samples from 92 participants in 26 households in Melbourne, Australia, in a 4-week period following the onset of infection with ancestral SARS-CoV-2 variants.

RESULTS

The secondary attack rate was 36% (24/66) when using nasopharyngeal swab (NPS) PCR positivity alone. However, when respiratory and nonrespiratory samples were combined with antibody responses in blood and saliva, the secondary attack rate was 76% (50/66). SARS-CoV-2 viral load of the index case and household isolation measures were key factors that determine secondary transmission. In 27% (7/26) of households, all family members tested positive by NPS for SARS-CoV-2 and were characterized by lower respiratory Ct values than low transmission families (Median 22.62 vs. 32.91; IQR 17.06-28.67 vs. 30.37-34.24). High transmission families were associated with enhanced plasma antibody responses to multiple SARS-CoV-2 antigens and the presence of neutralizing antibodies. Three distinguishing saliva SARS-CoV-2 antibody features were identified according to age (IgA1 to Spike 1, IgA1 to nucleocapsid protein (NP)), suggesting that adults and children generate distinct mucosal antibody responses during the acute phase of infection.

CONCLUSION

Utilizing respiratory and nonrespiratory PCR testing, along with the measurement of SARS-CoV-2-specific local and systemic antibodies, provides a more accurate assessment of infection within households and highlights some of the immunological differences in response between children and adults.

Advancing the Science of Vaccine Safety During the Coronavirus Disease 2019 (COVID-19) Pandemic and Beyond: Launching an International Network of Special Immunization Services

Within 2 years after the start of the coronavirus disease 2019 (COVID-19) pandemic, novel severe acute respiratory syndrome coronavirus 2 vaccines were developed, rigorously evaluated in large phase 3 trials, and administered to more than 5 billion individuals globally. However, adverse events of special interest (AESIs) have been described post-implementation, including myocarditis after receipt of messenger RNA (mRNA) vaccines and thrombosis with thrombocytopenia syndrome after receipt of adenoviral vector vaccines. AESIs are rare (<1 to 10/100 000 vaccinees) and less frequent than COVID-19 complications, though they have associated morbidity and mortality. The diversity of COVID-19 vaccine platforms (eg, mRNA, viral vector, protein) and rates of AESIs both between and within platforms (eg, higher rate of myocarditis after mRNA-1273 vs BNT162b2 vaccines) present an important opportunity to advance vaccine safety science. The International Network of Special Immunization Services has been formed with experts in vaccine safety, systems biology, and other relevant disciplines to study cases of AESIs and matched controls to uncover the pathogenesis of rare AESIs and inform vaccine development.

The safety of co-administration of Bacille Calmette-Guérin (BCG) and influenza vaccines

Background

With the emergence of novel vaccines and new applications for older vaccines, co-administration is increasingly likely. The immunomodulatory effects of BCG could theoretically alter the reactogenicity of co-administered vaccines. Using active surveillance in a randomised controlled trial, we aimed to determine whether co-administration of BCG vaccination changes the safety profile of influenza vaccination.

Methods

Participants who received influenza vaccine alone (Influenza group) were compared with those who also received BCG-Denmark vaccine in the contralateral arm (Influenza+BCG group). Data on the influenza vaccination site were collected using serial questionnaires and active follow-up for 3 months post vaccination.

Results

Of 1351 participants in the Influenza+BCG group and 1418 participants in the Influenza group, 2615 (94%) provided influenza vaccine safety data. There was no significant difference in the proportion of participants with any local adverse reaction between the Influenza+BCG group and the Influenza group (918/1293 [71.0%] versus (906/1322 [68.5%], p = 0.17). The proportion of participants reporting any pain, erythema and tenderness at the influenza vaccination site were similar in both groups. Swelling was less frequent (81/1293 [6.3%] versus 119/1322 (9.0%), p = 0.01) and the maximal diameter of erythema was smaller (mean 1.8 cm [SD 2.0] versus 3.0 cm [SD 2.5], p<0.001) in the Influenza+BCG group. Sixteen participants reported serious adverse events: 9 participants in the Influenza+BCG group and 7 in the Influenza group.

Conclusions

Adverse events following influenza vaccination are not increased when BCG is co-administered.

Myocarditis and myopericarditis cases following COVID-19 mRNA vaccines administered to 12-17-year olds in Victoria, Australia

IMPORTANCE

COVID-19 mRNA vaccine-associated myocarditis has previously been described; however specific features in the adolescent population are currently not well understood.

OBJECTIVE

To describe myocarditis adverse events following immunisation reported following any COVID-19 mRNA vaccines in the adolescent population in Victoria, Australia.

DESIGN

Statewide, population-based study.

SETTING

Surveillance of Adverse Events Following Vaccination in the Community (SAEFVIC) is the vaccine-safety service for Victoria, Australia.

PARTICIPANTS

All SAEFVIC reports of myocarditis and myopericarditis in 12-17-year-old COVID-19 mRNA vaccinees submitted between 22 February 2021 and 22 February 2022, as well as accompanying diagnostic investigation results where available, were assessed using Brighton Collaboration criteria for diagnostic certainty.

EXPOSURES

Any mRNA COVID-19 vaccine.

MAIN OUTCOMES/MMEASURE

Confirmed myocarditis as per Brighton Collaboration criteria (levels 1-3).

RESULTS

Clinical review demonstrated definitive (Brighton level 1) or probable (level 2) diagnoses in 75 cases. Confirmed myocarditis reporting rates were 8.3 per 100 000 doses in this age group. Cases were predominantly male (n=62, 82.7%) and post dose 2 (n=61, 81.3%). Rates peaked in the 16-17-year-old age group and were higher in males than females (17.7 vs 3.9 per 100 000, p=<0.001).The most common presenting symptoms were chest pain, dyspnoea and palpitations. A large majority of cases who had a cardiac MRI had abnormalities (n=33, 91.7%). Females were more likely to have ongoing clinical symptoms at 1-month follow-up (p=0.02).

CONCLUSION

Accurate evaluation and confirmation of episodes of COVID-19 mRNA vaccine-associated myocarditis enabled understanding of clinical phenotypes in the adolescent age group. Any potential vaccination and safety surveillance policies needs to consider age and gender differences.

The Impact of Australian Childhood Vaccination Mandates on Immunization Specialists and Their Interactions With Families

BACKGROUND

Recent global outbreaks of vaccine-preventable diseases, both before and since the coronavirus disease 2019 pandemic, have led to the introduction or strengthening of vaccine mandate policies to target vaccine refusal. Globally, there is wide variation in how governments and jurisdictions implement and enforce mandatory vaccination as well as the financial and educational consequences to those who fail to comply. We explored the impact of mandate vaccination policies on Australian Immunization Specialists who work in Specialist Immunization Clinics (SIC) for approving vaccine exemptions outside of the mandated criteria. In particular, their interactions with patients and families.

METHODS

A national, prospective, mixed methods, survey-based study conducted with members of the Australian Adverse Event Following Immunisation Clinical Assessment Network between February 2020 and June 2020.

RESULTS

Sixteen Immunization physicians and nurse practitioner specialists working in a SIC completed the survey. All sixteen respondents had been requested by parents to provide a Medical Exemptions at least once. 88% of respondents felt pressure to provide an exemption that was not medically justified according to legislation. Seventy-five percent of SIC consultants felt that the "No Jab" policies created a moderate or extreme amount of stress to both themselves and parents. All respondents reported experiencing hostility from parents with three respondents having received threats of violence.

CONCLUSIONS

Mandatory vaccination policies are associated with increased vaccination coverage but can result in widened financial and social inequity, and may harm families' relationships with health care providers. Countries considering the implementation of vaccination mandates should use the least restrictive health policies to ensure a balance between the public health and individual benefit whilst minimizing burdens on health care professionals, children and their parents.

Factors associated with severe respiratory syncytial virus disease in hospitalised children: a retrospective analysis

BACKGROUND

Early recognition of children at risk of severe respiratory syncytial virus (RSV) lower respiratory tract infection is important as it informs management decisions. We aimed to evaluate factors associated with severe disease among young children hospitalised with RSV infection.

METHODS

We conducted a retrospective cohort study of all children <2 years of age hospitalised for RSV lower respiratory tract infection at a single tertiary paediatric hospital over three RSV seasons (January 2017-December 2019). We classified children as having 'moderate' or 'severe' disease based on the level of respiratory intervention and used univariable and multivariable regression models to determine factors associated with severe disease.

RESULTS

Of 970 hospitalised children, 386 (40%) were classified as having 'severe' and 584 (60%) as having 'moderate' RSV disease. On multivariable analyses, age <2 months (OR: 2.3, 95% CI 1.6 to 3.3, p<0.0001), prematurity (OR: 1.6, 95% CI 1.1 to 2.4, p=0.02) and RSV-parainfluenza virus type 3 (PIV3) codetection (OR: 2.6, 95% CI 1.05 to 6.5, p=0.04) were independently associated with severe disease.

CONCLUSION

Younger age, prematurity and PIV3 codetection were associated with severe RSV disease in children <2 years of age hospitalised with RSV infection. The association between PIV3 and severe RSV disease is a novel finding and warrants further investigation.

Pertussis Disease and Antenatal Vaccine Effectiveness in Australian Children

BACKGROUND

Population-level studies of severe pertussis extending beyond infancy are sparse, and none in the context of antenatal vaccination. We compared hospitalized pertussis cases from birth to 15 years of age before and after introduction of antenatal immunization.

METHODS

Active surveillance of laboratory-confirmed pertussis hospitalizations in a national network of pediatric hospitals in Australia January 2012 to June 2019. Impact of maternal vaccination was assessed by vaccine effectiveness (VE) in cases and test-negative controls with <2 months of age and by before-after comparison of age distribution of cases. Among cases eligible for one or more vaccine doses, we examined proportions age-appropriately immunized and with comorbidities by age group.

RESULTS

Among 419 eligible cases, the proportion <2 months of age significantly decreased from 33.1% in 2012 to 2014 compared with 19.6% in 2016 to 2019 when mothers of only 4 of 17 (23.5%) cases <2 months of age had received antenatal vaccination. VE was estimated to be 84.3% (95% CI, 26.1-96.7). Across all years (2012-2019), of 55 cases 4-11 months of age, 21 (38%) had ≥2 vaccine doses, whereas among 155 cases ≥12 months of age, 122 (85.2%) had ≥3 vaccine doses. Prevalence of comorbidities (primarily cardiorespiratory) increased from 5 (2.1%) <6 months of age to 36 (24.2%) ≥12 months of age (P < 0.001), with 6/16 (38%) cases ≥12 months of age who required intensive care having comorbidities.

CONCLUSIONS

Below the age of 12 months, prevention of severe pertussis will be maximized by high maternal antenatal vaccine uptake and timeliness of infant vaccine doses. Despite full immunization, we found children ≥12 months of age accounted for 27% of hospitalizations <15 years, with 24% having comorbities, suggesting new vaccine strategies, such as additional doses or more immunogenic vaccines, require evaluation.

Comparison of Seroconversion in Children and Adults With Mild COVID-19

IMPORTANCE

The immune response in children with SARS-CoV-2 infection is not well understood.

OBJECTIVE

To compare seroconversion in nonhospitalized children and adults with mild SARS-CoV-2 infection and identify factors that are associated with seroconversion.

DESIGN, SETTING, AND PARTICIPANTS

This household cohort study of SARS-CoV-2 infection collected weekly nasopharyngeal and throat swabs and blood samples during the acute (median, 7 days for children and 12 days for adults [IQR, 4-13] days) and convalescent (median, 41 [IQR, 31-49] days) periods after polymerase chain reaction (PCR) diagnosis for analysis. Participants were recruited at The Royal Children's Hospital, Melbourne, Australia, from May 10 to October 28, 2020. Participants included patients who had a SARS-CoV-2-positive nasopharyngeal or oropharyngeal swab specimen using PCR analysis.

MAIN OUTCOMES AND MEASURES

SARS-CoV-2 immunoglobulin G (IgG) and cellular (T cell and B cell) responses in children and adults. Seroconversion was defined by seropositivity in all 3 (an in-house enzyme-linked immunosorbent assay [ELISA] and 2 commercial assays: a SARS-CoV-2 S1/S2 IgG assay and a SARS-CoV-2 antibody ELISA) serological assays.

RESULTS

Among 108 participants with SARS-CoV-2-positive PCR findings, 57 were children (35 boys [61.4%]; median age, 4 [IQR, 2-10] years) and 51 were adults (28 women [54.9%]; median age, 37 [IQR, 34-45] years). Using the 3 established serological assays, a lower proportion of children had seroconversion to IgG compared with adults (20 of 54 [37.0%] vs 32 of 42 [76.2%]; P < .001). This result was not associated with viral load, which was similar in children and adults (mean [SD] cycle threshold [Ct] value, 28.58 [6.83] vs 24.14 [8.47]; P = .09). In addition, age and sex were not associated with seroconversion within children (median age, 4 [IQR, 2-14] years for both seropositive and seronegative groups; seroconversion by sex, 10 of 21 girls [47.6%] vs 10 of 33 boys [30.3%]) or adults (median ages, 37 years for seropositive and 40 years for seronegative adults [IQR, 34-39 years]; seroconversion by sex, 18 of 24 women [75.0%] vs 14 of 18 men [77.8%]) (P > .05 for all comparisons between seronegative and seropositive groups). Symptomatic adults had 3-fold higher SARS-CoV-2 IgG levels than asymptomatic adults (median, 227.5 [IQR, 133.7-521.6] vs 75.3 [IQR, 36.9-113.6] IU/mL), whereas no differences were observed in children regardless of symptoms. Moreover, differences in cellular immune responses were observed in adults compared with children with seroconversion.

CONCLUSIONS AND RELEVANCE

The findings of this cohort study suggest that among patients with mild COVID-19, children may be less likely to have seroconversion than adults despite similar viral loads. This finding has implications for future protection after SARS-CoV-2 infection in children and for interpretation of serosurveys that involve children. Further research to understand why seroconversion and development of symptoms are potentially less likely in children after SARS-CoV-2 infection and to compare vaccine responses may be of clinical and scientific importance.

The 2018 annual cost burden for children under five years of age hospitalised with respiratory syncytial virus in Australia

Abstract

Respiratory syncytial virus (RSV) is one of the principal causes of acute bronchiolitis and respiratory tract infections in young children. Routine RSV surveillance in Australian children is limited; vaccines are in late stage development; prophylactic monoclonal antibody (mAb) treatment is available but expensive; and there has been uncertainty around the cost burden. The objective of this study was to determine the annual cost burden for children under five years of age hospitalised with RSV in a single health service in 2018, with national extrapolation based on published Australian prevalence data. The methods utilised individual patient-level cost data prospectively collected for hospitalised children under five years of age in a tertiary Melbourne paediatric hospital. Results were extrapolated to all Australian children under five years of age to determine the national annual health cost burden, from a healthcare sector perspective over a 12 month time horizon. The results included 363 children with a mean age of 9.2 months (standard deviation, SD: 8.5 months). The mean cost per child was $17,120 (SD: $37,562), with a combined health service cost of $6,214,439. The reported Australian hospitalisation rate for RSV in the target age group ranged from 2.2 to 4.5 per 1,000 children under five years of age, resulting in a 2018 extrapolated cost range of $59,218,844-$121,129,453 for the estimated 3,459-7,075 children affected (combined index and all-cause six-month readmissions). This study concluded that RSV represents a significant cost burden to Australia's health care system. These data are important for future health economic assessments of preventative therapies, such as new RSV mAb treatments and maternal/childhood RSV vaccines, and provides valuable insights to inform health care planning and health policy.

Immunisation status of children and adolescents with a new diagnosis of inflammatory bowel disease

BACKGROUND

Patients with Inflammatory Bowel Disease (IBD) are at increased risk of serious infections, including vaccine preventable diseases. Current evidence suggests uptake of additional recommended special risk vaccinations is low. Identification of IBD patients prior to commencing immunosuppressive therapy allows for optimisation of vaccination, including timely administration of live-attenuated and additional recommended vaccines, such as influenza and pneumococcal vaccines.

METHODS

Paediatric patients (0-18 years) seen at the tertiary Royal Children's Hospital, Melbourne, Australia, with a recent diagnosis of IBD were referred by the Gastroenterology Unit to our Specialist Immunisation Clinic (SIC) for assessment and provision of routine and special risk vaccines. Data was collected via a standardised REDCap questionnaire completed in or post attendance at the SIC and included serology results where available.

RESULTS

Sixty-nine paediatric patients were recruited to the study between 2014 and 2017. Median age at IBD diagnosis was 11.25 years (IQR 4.64 years), with median time between diagnosis and SIC review of 0.88 years (IQR 2.84 years). At initial review 84.1% (58/69) of patients were up to date with vaccines on the Australian National Immunisation Program (NIP) schedule. Of those who were tested, serological evidence of immunity was demonstrated in 38.3% (23/60) of patients for Hepatitis B, 66.7% (36/54) for measles, 51.9% (28/54) for rubella and 41.9% (26/62) for Varicella Zoster Virus. Prior to SIC review 47.8% (33/69) had additional vaccinations and 92.8% (64/69) had vaccinations administered in the 12 months following SIC assessment. The Pneumococcal conjugate vaccine (76.8%, 53/69) was the most commonly administered vaccine after SIC review, followed by influenza vaccine (69.6%, 48/69). Within 12 months of SIC review 43.5% (30/69) of patients had completed the schedule and were up-to-date as recommended by the SIC.

CONCLUSIONS

Children with IBD and other special risk groups can benefit from early referral to a SIC team to ensure optimal administration of routine and additionally recommended vaccines, especially live and additional special risk vaccines. The value of optimising immunisations could also be applied to other special risk groups, including adult IBD cohorts, particularly those commencing newer biologic immunosuppressive medications.

COVID-19 in children. II: Pathogenesis, disease spectrum and management

The global disruption of the COVID-19 pandemic has impacted the life of every child either directly or indirectly. This review explores the pathophysiology, immune response, clinical presentation and treatment of COVID-19 in children, summarising the most up-to-date data including recent developments regarding variants of concern. The acute infection with SARS-CoV-2 is generally mild in children, whilst the post-infectious manifestations, including paediatric inflammatory multisystem syndrome temporally associated with SARS-CoV-2 (PIMS-TS) and 'long COVID' in children, are more complex. Given that most research on COVID-19 has focused on adult cohorts and that clinical manifestations, treatment availability and impacts differ markedly in children, research that specifically examines COVID-19 in children needs to be prioritised.

COVID-19 in children: I. Epidemiology, prevention and indirect impacts

Children globally have been profoundly impacted by the coronavirus disease 2019 (COVID-19) pandemic. This review explores the direct and indirect public health impacts of COVID-19 on children. We discuss in detail the transmission dynamics, vaccination strategies and, importantly, the 'shadow pandemic', encompassing underappreciated indirect impacts of the pandemic on children. The indirect effects of COVID-19 will have a long-term impact beyond the immediate pandemic period. These include the mental health and wellbeing risks, disruption to family income and attendant stressors including increased family violence, delayed medical attention and the critical issue of prolonged loss of face-to-face learning in a normal school environment. Amplification of existing inequities and creation of new disadvantage are likely additional sequelae, with children from vulnerable families disproportionately affected. We emphasise the responsibility of paediatricians to advocate on behalf of this vulnerable group to ensure the longer-term effects of COVID-19 public health responses on the health and wellbeing of children are fully considered.

Influenza hospitalizations in Australian children 2010-2019: The impact of medical comorbidities on outcomes, vaccine coverage, and effectiveness

BACKGROUND

Children with comorbidities are at greater risk of severe influenza outcomes compared with healthy children. In Australia, influenza vaccination was funded for those with comorbidities from 2010 and all children aged <5 years from 2018. Influenza vaccine coverage remains inadequate in children with and without comorbidities.

METHODS

Children ≤16 years admitted with acute respiratory illness and tested for influenza at sentinel hospitals were evaluated (2010-2019). Multivariable regression was used to identify predictors of severe outcomes. Vaccine effectiveness was estimated using the modified incidence density test-negative design.

RESULTS

Overall, 6057 influenza-confirmed hospitalized cases and 3974 test-negative controls were included. Influenza A was the predominant type (68.7%). Comorbidities were present in 40.8% of cases. Children with comorbidities were at increased odds of ICU admission, respiratory support, longer hospitalizations, and mortality. Specific comorbidities including neurological and cardiac conditions increasingly predisposed children to severe outcomes. Influenza vaccine coverage in influenza negative children with and without comorbidities was low (33.5% and 17.9%, respectively). Coverage improved following introduction of universal influenza vaccine programs for children <5 years. Similar vaccine effectiveness was demonstrated in children with (55% [95% confidence interval (CI): 45; 63%]) and without comorbidities (57% [(95%CI: 44; 67%]).

CONCLUSIONS

Comorbidities were present in 40.8% of influenza-confirmed admissions and were associated with more severe outcomes. Children with comorbidities were more likely experience severe influenza with ICU admission, mechanical ventilation, and in-hospital morality. Despite demonstrated vaccine effectiveness in those with and without comorbidities, vaccine coverage was suboptimal. Interventions to increase vaccination are expected to reduce severe influenza outcomes.

Prospective characterisation of SARS-CoV-2 infections among children presenting to tertiary paediatric hospitals across Australia in 2020: a national cohort study

OBJECTIVE

To present Australia-wide data on paediatric COVID-19 and multisystem inflammatory syndromes to inform health service provision and vaccination prioritisation.

DESIGN

Prospective, multicentre cohort study.

SETTING

Eight tertiary paediatric hospitals across six Australian states and territories in an established research surveillance network-Paediatric Active Enhanced Disease (PAEDS).

PARTICIPANTS

All children aged <19 years with SARS-CoV-2 infection including COVID-19, Paediatric Inflammatory Multisystem Syndrome Temporally Associated with SARS-CoV-2 (PIMS-TS) and Kawasaki-like disease TS infection (KD-TS) treated at a PAEDS site from 24 March 2020 to 31 December 2020.

INTERVENTION

Laboratory-confirmed SARS-CoV-2 infection.

MAIN OUTCOME

Incidence of severe disease among children with COVID-19, PIMS-TS and KD-TS. We also compared KD epidemiology before and during the COVID-19 pandemic.

RESULTS

Among 386 children with SARS-CoV-2 infection, 381 (98.7%) had COVID-19 (median 6.3 years (IQR 2.1-12.8),53.3% male) and 5 (1.3%) had multisystem inflammatory syndromes (PIMS-TS, n=4; KD-TS, n=1) (median 7.9 years (IQR 7.8-9.8)). Most children with COVID-19 (n=278; 73%) were Australian-born from jurisdictions with highest community transmission. Comorbidities were present in 72 (18.9%); cardiac and respiratory comorbidities were most common (n=32/72;44%). 37 (9.7%) children with COVID-19 were hospitalised, and two (0.5%) required intensive care. Postinfective inflammatory syndromes (PIMS-TS/KD-TS) were uncommon (n=5; 1.3%), all were hospitalised and three (3/5; 60%) required intensive care management. All children recovered and there were no deaths. KD incidence remained stable during the pandemic compared with prepandemic.

CONCLUSIONS

Most children with COVID-19 had mild disease. Severe disease was less frequent than reported in high prevalence settings. Preventative strategies, such as vaccination, including children and adolescents, could reduce both the acute and postinfective manifestations of the disease.

Children and Adults in a Household Cohort Study Have Robust Longitudinal Immune Responses Following SARS-CoV-2 Infection or Exposure

Children have reduced severity of COVID-19 compared to adults and typically have mild or asymptomatic disease. The immunological mechanisms underlying these age-related differences in clinical outcomes remain unexplained. Here, we quantify 23 immune cell populations in 141 samples from children and adults with mild COVID-19 and their PCR-negative close household contacts at acute and convalescent time points. Children with COVID-19 displayed marked reductions in myeloid cells during infection, most prominent in children under the age of five. Recovery from infection in both children and adults was characterised by the generation of CD8 T_CM and CD4 T_CM up to 9 weeks post infection. SARS-CoV-2-exposed close contacts also had immunological changes over time despite no evidence of confirmed SARS-CoV-2 infection on PCR testing. This included an increase in low-density neutrophils during convalescence in both exposed children and adults, as well as increases in CD8 T_CM and CD4 T_CM in exposed adults. In comparison to children with other common respiratory viral infections, those with COVID-19 had a greater change in innate and T cell-mediated immune responses over time. These findings provide new mechanistic insights into the immune response during and after recovery from COVID-19 in both children and adults.

ATAGI 2021 annual statement on immunisation Last updated: 19 September 2021

The Australian Technical Advisory Group on Immunisation (ATAGI) 2021 Annual Statement on Immunisation is the first publication in this series. It highlights the key successes, trends and challenges in the use of vaccines and control of vaccine preventable diseases (VPDs) in Australia in 2020. It also signals ATAGI’s priority actions for addressing key issues for 2021 and beyond.