RESUMEN
AusVaxSafety (Australias active safety surveillance system) used SMS/email delivered surveys to actively solicit the short-term (within first 3 days after vaccination) adverse event profile of mRNA COVID-19 vaccines in children (aged 5-15 years) by age, dose, brand and pre-existing comorbidity. 392,268 survey responses for children aged 5-15 who received a COVID-19 vaccine between July 2021-May 2022 (211,994 following BNT162b2 10mcg in children aged 5-11 years, 173,329 following BNT162b2 30mcg and 6,945 following mRNA-1273 100mcg in adolescents aged 12-15 years) were analysed. Adverse event rates were higher following dose 2 and 3 compared to dose 1 after all vaccines and highest following dose 2 of mRNA-1273 in 12-15 years. Fever was low in the youngest children (5 years old, any dose; 1,090/26,181 (4%)). Medical review rates remained low (0.3% overall) and impact on daily activities was also low (7% overall). No self-reported cases of myocarditis or pericarditis were identified. Ongoing active safety surveillance of lower dose mRNA vaccines in children under 5 years old is required to better understand safety as the vaccines roll out into this population age-group.
RESUMEN
Rapidly identifying and isolating people with acute SARS-CoV-2 infection has been a core strategy to contain COVID-19 in Australia, but a proportion of infections go undetected. We estimated SARS-CoV-2 specific antibody prevalence (seroprevalence) among blood donors in metropolitan Melbourne following a COVID-19 outbreak in the city between June and September 2020. The aim was to determine the extent of infection spread and whether seroprevalence varied demographically in proportion to reported cases of infection. The design involved stratified sampling of residual specimens from blood donors (aged 20-69 years) in three postcode groups defined by low (<3 cases/1,000 population), medium (3-7 cases/1,000 population) and high (>7 cases/1,000 population) COVID-19 incidence based on case notification data. All specimens were tested using the Wantai SARS-CoV-2 total antibody assay. Seroprevalence was estimated with adjustment for test sensitivity and specificity for the Melbourne metropolitan blood donor and residential populations, using multilevel regression and poststratification. Overall, 4,799 specimens were collected between 23 November and 17 December 2020. Seroprevalence for blood donors was 0.87% (90% credible interval: 0.25-1.49%). The highest estimates, of 1.13% (0.25-2.15%) and 1.11% (0.28-1.95%), respectively, were observed among donors living in the lowest socioeconomic areas (Quintiles 1 and 2) and lowest at 0.69% (0.14-1.39%) among donors living in the highest socioeconomic areas (Quintile 5). When extrapolated to the Melbourne residential population, overall seroprevalence was 0.90% (0.26-1.51%), with estimates by demography groups similar to those for the blood donors. The results suggest a lack of extensive community transmission and good COVID-19 case ascertainment based on routine testing during Victorias second epidemic wave. Residual blood donor samples provide a practical epidemiological tool for estimating seroprevalence and information on population patterns of infection, against which the effectiveness of ongoing responses to the pandemic can be assessed.
RESUMEN
Objective(s)To describe the severity and clinical spectrum of SARS-CoV-2 infection in Australian children during the 2021 Delta outbreak. Design, Setting & ParticipantsA prospective cohort study of children <16 years with a positive SARS-CoV-2 nucleic acid test cared for by the Sydney Childrens Hospital Network (SCHN) virtual and inpatient medical teams between 1 June - 31 October 2021. Main outcome measuresDemographic and clinical data from all admitted patients and a random sample of outpatients managed under the SCHN virtual care team were analysed to identify risk factors for admission to hospital. ResultsThere were 17,474 SARS-CoV-2 infections in children <16 years in NSW during the study period, of whom 11,985 (68.6%) received care coordinated by SCHN. Twenty one percent of children infected with SARS-CoV-2 were asymptomatic. For every 100 SARS-CoV-2 infections in children <16 years, 1.26 (95% CI 1.06 to 1.46) required hospital admission for medical care; while 2.46 (95% CI 2.18 to 2.73) required admission for social reasons only. Risk factors for hospitalisation for medical care included age <6 months, a history of prematurity, age 12 to <16 years, and a history of medical comorbidities (aOR 7.23 [95% CI 2.92 to 19.4]). Of 17,474 infections, 15 children (median age 12.8years) required ICU admission; and 294 children required hospital admission due to social or welfare reasons. ConclusionThe majority of children with SARS-CoV-2 infection (Delta variant) had asymptomatic or mild disease. Hospitalisation was uncommon and occurred most frequently in young infants and adolescents with comorbidities. More children were hospitalised for social reasons than for medical care.