The WHO declared COVID-19 a pandemic on March 11th, 2020. This serious outbreak and the precipitously increasing numbers of deaths worldwide necessitated the urgent need to develop an effective severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine. The development of COVID-19 vaccines has moved quickly. In this study, we assessed the efficacy, safety, and immunogenicity of an inactivated (SARS-CoV-2) vaccine. We conducted a randomized, double-blind, placebo-controlled trial to evaluate the efficacy, immunogenicity, and safety of an inactivated SARS-CoV-2 vaccine and its lot-to-lot consistency. A total of 1620 healthy adults aged 18–59 years were randomly assigned to receive 2 injections of the trial vaccine or placebo on a day 0 and 14 schedule. This article was based on an interim report completed within 3 months following the last dose of study vaccine. The interim analysis includes safety and immunogenicity data for 540 participants in the immunogenicity subset and an efficacy analysis of the 1620 subjects. For the safety evaluation, solicited and unsolicited adverse events were collected after the first and second vaccination within 14 and 28 days, respectively. Blood samples were collected for an antibody assay before and 14 days following the second dose. Most of the adverse reactions were in the solicited category and were mild in severity. Pain at the injection site was the most frequently reported symptom. Antibody IgG titer determined by enzyme-linked immunosorbent assay was 97.48% for the seroconversion rate. Using a neutralization assay, the seroconversion rate was 87.15%. The efficacy in preventing symptomatic confirmed cases of COVID-19 occurring at least 14 days after the second dose of vaccine using an incidence rate was 65.30%. From the 3-month interim analysis, the vaccine exhibited a 65.30% efficacy at preventing COVID-19 illness with favorable safety and immunogenicity profiles.

Potentially pathogenic bacteria Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, and Staphylococcus aureus are commonly carried in the nasopharynx of young children. Host and environmental factors have been linked with pathogen carriage, and in many studies rural children have higher carriage rates than their urban counterparts. There are few published data on what factors contribute to increased pathogen density. The objectives of this study were to identify risk factors for nasopharyngeal carriage and density of S. pneumoniae, H. influenzae, M. catarrhalis, and S. aureus in young children in Indonesia. Risk factor analysis was done using data on bacterial carriage and participant characteristics from a cross-sectional study that enrolled 302 children aged 12–24 months living in urban or semi-rural areas of Indonesia. Associations between host factors and odds of pathogen carriage were explored using logistic regression. Characteristics identified to be independent predictors of carriage by univariable analysis, as well as those that differed between urban and semi-rural participants, were included in multivariable models. Risk factors for increased pathogen density were identified using linear regression analysis. No differences in carriage prevalence between urban and semi-rural children were observed. Multiple children under the age of 5 years in the household (< 5y) and upper respiratory tract infection (URTI) symptoms were associated with S. pneumoniae carriage, with adjusted odds ratios (aOR) of 2.17 (95% CI 1.13, 4.12) and 2.28 (95% CI 1.15, 4.50), respectively. There was some evidence that URTI symptoms (aOR 1.94 [95% CI 1.00, 3.75]) were associated with carriage of M. catarrhalis. Children with URTI symptoms (p = 0.002), and low parental income (p = 0.011) had higher S. pneumoniae density, whereas older age was associated with lower S. pneumoniae density (p = 0.009). URTI symptoms were also associated with higher M. catarrahlis density (p = 0.035). Low maternal education (p = 0.039) and multiple children < 5y (p = 0.021) were positively associated with H. influenzae density, and semi-rural residence was associated with higher S. aureus density (p < 0.001). This study provides a detailed assessment of risk factors associated with carriage of clinically-relevant bacteria in Indonesian children, and new data on host factors associated with pathogen density.

The first two years of life, including the period from conception to 2 years of age, are very important for a child’s growth and development. This study sought to describe the developmental status and the environmental factors that influence it in children aged 6 months to 2 years in urban and rural areas. The research sites were purposively selected: specific health centres in the city of Bandung and West Bandung district were chosen and the study was conducted from November to December 2022. A cross-sectional study was conducted with healthy children aged 6 months to 2 years and their parents, who agreed to participate in the study. Researchers performed developmental tests using the Developmental Pre-screening Questionnaire with classifications for normal developmental test results and developmental delays. During the study, 346 children met the inclusion criteria, resulting in a sample of 164 (47.4%) boys and 182 (52.6%) girls. There were no significant differences among children with developmental delays in urban and rural areas. The factors that influence the possibility of developmental delays in the two research areas were the child’s age, exposure to screen time, stimulation, nutritional status, and the use of the mother–child handbook.

Air pollution is an unseen threat to children’s health because it may increase the risk of respiratory infection, atopy, and asthma, and also alter gut microbiota compositions. The impact of air pollution on children’s health has not been firmly established. A literature review followed by a series of discussions among experts were performed to develop a theoretical framework on how air pollution could affect various bodily organs and functions in children. We invited experts from different backgrounds, such as paediatricians, nutritionists, environmental health experts, and occupational health experts, to provide their views on this matter. This report summarizes the discussion of multidisciplinary experts on the impact of air pollution on children’s health. The report begins with a review of air pollution’s impact on allergy and immunology, neurodevelopment, and cardiometabolic risks, and ends with the conceptualization of a theoretical framework. While the allergic and immunological pathway is one of the most significant pathways for air pollution affecting children’s health in which microbiotas also play a role, several pathways have been proposed regarding the ability to affect neurodevelopment and cardiometabolic risk. Further research is required to confirm the link between air pollution and the gut microbiota pathway.

The new combination of DTwP-HB-Hib vaccines has been developed in Indonesia following World Health Organization (WHO) recommendation and integrated into national immunization program. The aims of the study were to measure 1) antibody persistence 12–18 months after a primary series, 2) immune response and safety after a booster dose of DTwP-HB-Hib. This was a multi-center, open-labeled, prospective, interventional study. Subjects who had received complete primary dose of DTwP-HB-Hib vaccine from the previous phase III trial were recruited in this trial. Subjects were given one dose of DTwP-HB-Hib (Pentabio®) booster at age 18–24 months old. Diphtheria, tetanus, pertussis, hepatitis B, Hemophilus influenza type B antibodies were measured before and after booster to determine antibody persistence and immune response. Vaccine adverse events were assessed immediately and monitored until 28 days after the booster recorded with parent’s diary cards. There were 396 subjects who completed the study. Increased proportion of seroprotected subjects from pre-booster to post-booster were noted in all vaccine antigens: 74.5 to 99.7% for diphtheria; 100 to 100% for tetanus; 40.4 to 95.5% for pertussis; 90.2 to 99.5% for hepatitis B; and 97.7 to 100% for Hib. Common systemic adverse events (AEs) were irritability (23.7–25%) and fever (39.9–45.2%). Local AEs such as redness, swelling, and induration were significantly less common in the thigh group (7.7, 11.3, and 7.1%) than in the deltoid group (28.9, 30.7, and 25%) (P < 0.001). Most AEs were mild and resolved spontaneously within three-day follow-up period. Booster of DTwP-HB-Hib vaccine at age 18–24 months is required to achieve and maintain optimal protective antibody. The vaccine is safe and immunogenic to be used for booster vaccination. NCT02095314 (retrospectively registered, March 24, 2014).