Healthcare workers’ COVID-19 vaccination coverage is important for staff and patient safety, workforce capacity and patient uptake. We aimed to identify COVID-19 vaccine intentions, factors associated with uptake and information needs for healthcare workers in Victoria, Australia. We administered a cross-sectional online survey to healthcare workers in hospitals, primary care and aged or disability care settings (12 February–26 March 2021). The World Health Organization Behavioural and Social Drivers of COVID-19 vaccination framework informed survey design and framing of results. Binary regression results adjusted for demographics provide risk differences between those intending and not intending to accept a COVID-19 vaccine. In total, 3074 healthcare workers completed the survey. Primary care healthcare workers reported the highest intention to accept a COVID-19 vaccine (84%, 755/898), followed by hospital-based (77%, 1396/1811) and aged care workers (67%, 243/365). A higher proportion of aged care workers were concerned about passing COVID-19 to their patients compared to those working in primary care or hospitals. Only 25% felt they had sufficient information across five vaccine topics, but those with sufficient information had higher vaccine intentions. Approximately half thought vaccines should be mandated. Despite current high vaccine rates, our results remain relevant for booster programs and future vaccination rollouts.

Background: Measles infections cause significant morbidity and mortality in low- and middle-income countries (LMICs), especially in infants under 9 months of age. Measles seroprevalence data in infants too young to be vaccinated can identify immunity gaps to inform immunization strategies. Our systematic review and meta-analysis describes measles seroprevalence in infants <9 months in LMICs. Methods: We systematically searched journal articles and conference abstracts from 1 January 2018 to 25 December 2024 across 10 databases and registers (PROSPERO, CRD42023429586). We included observational studies presenting measles antibody seroprevalence data from infants <9 months in LMICs. Studies underwent dual reviewer screening and risk of bias was assessed using an adapted Joanna Briggs Institute tool. Seropositivity estimates were pooled using a random-effects inverse variance model. We performed subgroup analyses by country income level, measles vaccine coverage, and measles incidence. Results: Among 1421 studies identified, 34 were included. Most studies were from middle-income countries (n = 30/34) using hospital/health-center data (n = 22/34). Risk of bias was generally low or moderate (n = 33/34). The meta-analysis included 20 studies (n = 8230 infants) with high interstudy heterogeneity. Pooled seropositivity was highest at birth (81%; 95% confidence interval [CI], 75%–88%), decreasing to 30% (95% CI, 24%–35%) by 4 months, and lowest at 7 months (18%; 95% CI, 0%–41%). Subgroup analyses showed minimal differences between categories. Conclusions: Seventy percent of infants are seronegative by 4 months old and unprotected from measles before their first vaccine dose at 9–12 months. Early administration of measles-containing vaccines could provide sustained protection throughout infancy.

Rotavirus vaccines are less effective in high mortality regions. A rotavirus vaccine administered at birth may overcome challenges to vaccine uptake posed by a complex gut microbiome. We investigated the association between the microbiome and vaccine responses following RV3-BB vaccine (G3P[6]) administered in a neonatal schedule (dose 1: 0-5 days), or infant schedule (dose 1: 6-8 weeks) in Indonesia (Phase 2b efficacy study) (n = 478 samples/193 infants) (ACTRN12612001282875) and in Malawi (Immunigenicity study) (n = 355 samples/186 infants) (NCT03483116). Vaccine responses assessed using anti-rotavirus IgA seroconversion (IgA), stool shedding of vaccine virus and vaccine take (IgA seroconversion and/or shedding). Here we report, high alpha diversity, beta diversity differences and high abundance of Bacteroides is associated with positive vaccine take and shedding following RV3-BB administered in the neonatal schedule, but not with IgA seroconversion, or in the infant schedule. Higher alpha diversity was associated with shedding after three doses of RV3-BB in the neonatal schedule compared to non-shedders, or the placebo group. High abundance of Streptococcus and Staphylococcus is associated with no shedding in the neonatal schedule group. RV3-BB vaccine administered in a neonatal schedule modulates the early microbiome environment and presents a window of opportunity to optimise protection from rotavirus disease.

Objective: Current prevention and/or treatment options for respiratory syncytial virus (RSV) infections are limited as no vaccine is available. Prophylaxis with palivizumab is very expensive and requires multiple intramuscular injections over the RSV season. Here we present proof-of-concept data using nebulized palivizumab delivery as a promising new approach for the prevention or treatment of severe RSV infections, documenting both aerosol characteristics and pulmonary deposition patterns in the lungs of lambs. Design: Prospective animal study. Setting: Biosecurity Control Level 2-designated large animal research facility at the Murdoch Children’s Research Institute, Melbourne, Australia. Subjects: Four weaned Border-Leicester/Suffolk lambs at 5 months of age. Interventions: Four lambs were administered aerosolized palivizumab conjugated to Tc-99m, under gaseous anesthesia, using either the commercially available AeroNeb Go^® or the investigational HYDRA device, placed in-line with the inspiratory limb of a breathing circuit. Lambs were scanned in a single-photon emission computed tomography (SPECT/CT) scanner in the supine position during the administration procedure. Measurements and Main Results: Both the HYDRA and AeroNeb Go^® produced palivizumab aerosols in the 1–5 µm range with similar median (geometric standard deviation and range) aerosol droplet diameters for the HYDRA device (1.84 ± 1.40 μm, range = 0.54–5.41μm) and the AeroNeb Go^® (3.07 ± 1.56 μm, range = 0.86–10 μm). Aerosolized palivizumab was delivered to the lungs at 88.79–94.13% of the total aerosolized amount for all lambs, with a small proportion localized to either the trachea or stomach. No difference between devices were found. Pulmonary deposition ranged from 6.57 to 9.25% of the total dose of palivizumab loaded in the devices, mostly in the central right lung. Conclusions: Aerosolized palivizumab deposition patterns were similar in all lambs, suggesting a promising approach in the control of severe RSV lung infections.

The use of pneumococcal conjugate vaccine (PCV) schedules with fewer doses are being considered to reduce costs and improve access, particularly in low- and middle-income countries. While several studies have assessed their immunogenicity, there are limited data on their potential for long-term immune protection, as assessed by pneumococcal serotype-specific memory B cell (B_mem) responses. This current study reports secondary outcome data that aims to compare B_mem responses following reduced-dose (0 + 1 and 1 + 1) schedules of PCV10 and PCV13 in Vietnamese infants from our randomised-controlled trial (trial registration number NCT03098628). Following vaccination at 12 months of age, B_mem levels for most serotypes peaked seven days post-vaccination and were higher in magnitude for the 1 + 1 than 0 + 1 schedules and for PCV13 than PCV10. Furthermore, B_mem did not wane as rapidly as IgG levels by 24 months of age. Further studies are needed to assess the use of B_mem as markers of long-term protection against pneumococcal carriage and disease, which is crucial to generate data for immunisation program decision-making.

High titres of rotavirus-specific maternal antibodies may contribute to lower rotavirus vaccine efficacy in low- and middle-income countries (LMICs). RV3-BB vaccine (G3P[6]) is based on a neonatal rotavirus strain that replicates well in the newborn gut in the presence of breast milk. This study investigated the association between maternal serum antibodies and vaccine response in infants administered the RV3-BB vaccine. Serum was collected antenatally from mothers of 561 infants enrolled in the RV3-BB Phase II study conducted in Blantyre, Malawi, and analysed for rotavirus-specific serum IgA and IgG antibodies using enzyme-linked immunosorbent assay. Infant vaccine take was defined as cumulative IgA seroconversion (≥3 fold increase) and/or stool vaccine shedding. Maternal IgA or IgG antibody titres did not have a negative impact on vaccine-like stool shedding at any timepoint. Maternal IgG (but not IgA) titres were associated with reduced take post dose 1 (p < 0.005) and 3 (p < 0.05) in the neonatal vaccine schedule group but not at study completion (week 18). In LMICs where high maternal antibodies are associated with low rotavirus vaccine efficacy, RV3-BB in a neonatal or infant vaccine schedule has the potential to provide protection against severe rotavirus disease.