Wastewater-based epidemiology surveillance as an early warning system for SARS-CoV-2 in Indonesia.

BACKGROUND: Wastewater-based epidemiology (WBE) surveillance has been proposed as an early warning system (EWS) for community SARS-CoV-2 transmission. However, there is limited data from low-and middle-income countries (LMICs). This study aimed to assess the ability of WBE surveillance to detect SARS-CoV-2 in formal and informal environments in Indonesia using different methods of sample collection, to compare WBE data with patterns of clinical cases of COVID-19 within the relevant communities, and to assess the WBE potential to be used as an EWS for SARS-CoV-2 outbreaks within a community. MATERIALS AND METHODS: We conducted WBE surveillance in three districts in Yogyakarta province, Indonesia, over eleven months (27 July 2021 to 7 January 2022 [Delta wave]; 18 January to 3 June 2022 [Omicron wave]). Water samples using grab, and/or passive sampling methods and soil samples were collected either weekly or fortnightly. RNA was extracted from membrane filters from processed water samples and directly from soil. Reverse-transcription quantitative real-time polymerase chain reaction (RT-qPCR) was performed to detect the SARS-CoV-2 N and ORF1ab genes. RESULTS: A total of 1,582 samples were collected. Detection rates of SARS-CoV-2 in wastewater reflected the incidence of community cases, with rates of 85% at the peak to 2% at the end of the Delta wave and from 94% to 11% during the Omicron wave. A 2-week lag time was observed between the detection of SARS-CoV-2 in wastewater and increasing cases in the corresponding community. CONCLUSION: WBE surveillance for SARS-CoV-2 in Indonesia was effective in monitoring patterns of cases of COVID-19 and served as an early warning system, predicting the increasing incidence of COVID-19 cases in the community.

Timeliness of routine childhood vaccinations in Indonesian infants in the first year of life.

BACKGROUND: Vaccines have proven to be one of the most effective strategies to control infectious diseases and contributed to childhood survival. While high vaccine coverages provide individual's and herd immunity, age-appropriate vaccination or vaccine timeliness is important for maximum vaccine's protection, but often not evaluated. We aimed to describe the timeliness of childhood vaccination for Indonesian infants and identify risk factors associated with delayed vaccination. METHODS: This study was a sub-study of the Indonesian Pneumonia and Vitamin D status (IPAD) study, a community-based cohort study to investigate pneumonia incidence in two districts in Yogyakarta province, Indonesia. Socio-demographic data were obtained from structured interviews and vaccine status was obtained from maternal and child health records. Timely vaccination was defined if the vaccine was received between four days or less before and within 28 days after the recommended age of vaccination. RESULTS: 359 (85%) out of 422 IPAD participants and their immunisation records were included. Between December 2015 and December 2017, vaccination coverage was high and ranged from 96.1% (Measles) to 100% (DTP-HepB-Hib 1). However, two thirds (67%, 242/359) of all participants had received either early or late vaccines, with dose 2 IPV (40%, 143/356), dose 3 IPV (56%, 196/349) and dose 3 DTP-HepB-Hib (29%, 103/354) most delayed, and only 1% received early doses. The main risk factors for untimely vaccination were if the infant was born in a private practice versus in a public health facility (AOR 1.90; 95% CI: 1.18-3.07) and rural residence (AOR 1.84; 95% CI: 1.15-2.94). CONCLUSIONS: Despite high vaccine coverage for Indonesian infants (>95%), two thirds (67%) of infants had untimely vaccinations, with dose 3 IPV (56%) the most delayed. Future strategies should focus on coordination between government, health care providers, and carers to ensure timely access and vaccination of infants to ensure adherence to vaccination schedules.

The prevalence and determinants of vitamin D deficiency in Indonesian infants at birth and six months of age.

BACKGROUND: Vitamin D deficiency in infants has been associated with an increased risk of a number of diseases but there are limited data on the prevalence and determinants of vitamin D deficiency from tropical settings with high infant morbidity and mortality. OBJECTIVE: To determine the prevalence and determinants of vitamin D deficiency in infants at birth and at six months of age in Yogyakarta province, Indonesia. DESIGN: Serum vitamin D of eligible infants was measured in cord blood at birth and at six months of age. Factors associated with vitamin D deficiency (serum 25-hydroxyvitamin D <50 nmol/L) were collected prospectively monthly from birth and concentrations measured by liquid chromatography-tandem mass spectrometry. Independent risk factors were identified by multiple logistic regression. RESULTS: Between December 2015 to December 2017, 350 maternal-newborn participants were recruited and followed up. Vitamin D deficiency was detected in 90% (308/344) of cord blood samples and 13% (33/255) of venous blood samples at six months. Longer time outdoors (≥2 hours per day) and maternal multivitamin intake containing vitamin D during pregnancy were protective against vitamin D deficiency at birth (AOR: 0.10, 95% CI: 0.01-0.90 and AOR: 0.21, 95% CI: 0.06-0.68, respectively). Risk factors for vitamin D deficiency at six months included lower cumulative skin-sun exposure score (AOR: 1.12, 95% CI: 1.04-1.20), severe vitamin D deficiency at birth (AOR: 7.73, 95% CI: 1.20-49.60) and exclusive breastfeeding (AOR: 2.64, 95% CI: 1.07-6.49) until six months. Among exclusively breast fed (EBF) infants, a higher skin-sun exposure score was associated with reduced vitamin D deficiency risk. CONCLUSION: In equatorial regions, the role of 'safe' morning sun exposure in infants and mothers in populations with medium to dark brown skin pigmentation and effective interventions to prevent vitamin D deficiency in newborns and EBF infants, need further consideration and evaluation.