Breastfeeding challenges and opportunities during COVID-19 in Hong Kong.

Barriers to sustain breastfeeding could be time and place specific. Here, we summarise new and old challenges to breastfeeding during COVID-19 pandemic in Hong Kong, some of which were obtained from qualitative in-depth interviews with health-care professionals. We document how unnecessary massive mother-baby separations in hospitals and doubts in COVID-19 vaccine safety seriously harm breastfeeding. We also discuss how the trends and increase in acceptance of receiving post-natal care from family doctors, online-antenatal class, work-from-home policy and telemedicine implicate new strategies to protect, promote and support breastfeeding during and after the pandemic. The challenges from the COVID-19 pandemic on breastfeeding have revealed new opportunities to support breastfeeding in Hong Kong and similar settings where exclusive breastfeeding for 6 months is still not the norm.

Higher Viral Load of Emerging Norovirus GII.P16-GII.2 than Pandemic GII.4 and Epidemic GII.17, Hong Kong, China.

We compared viral load of emerging recombinant norovirus GII.P16-GII.2 with those for pandemic GII.Pe-GII.4 and epidemic GII.P17-GII.17 genotypes among inpatients in Hong Kong. Viral load of GII.P16-GII.2 was higher than those for other genotypes in different age groups. GII.P16-GII.2 is as replication competent as the pandemic genotype, explaining its high transmissibility and widespread circulation.

Bimodal Seasonality and Alternating Predominance of Norovirus GII.4 and Non-GII.4, Hong Kong, China, 2014-20171.

We report emerging subtropical bimodal seasonality and alternating predominance of norovirus GII.4 and non-GII.4 genotypes in Hong Kong. GII.4 predominated in summer and autumn months and affected young children, whereas emergent non-GII.4 genotypes predominated in winter months and affected all age groups. This highly dynamic epidemiology should inform vaccination strategies.

The association of breastfeeding with insulin resistance at 17 years: Prospective observations from Hong Kong's "Children of 1997" birth cohort.

Breastfeeding has many benefits for mother and infant. Whether breastfeeding also protects against type 2 diabetes is unclear. To clarify the role of breastfeeding in type 2 diabetes, we assessed the association of breastfeeding with insulin resistance in late adolescence in a birth cohort from a non-Western setting where breastfeeding was not associated with higher socio-economic position. We used multivariable linear regression, with multiple imputation and inverse probability weighting, to examine the adjusted associations of contemporaneously reported feeding in the first 3 months of life (exclusively breastfed, mixed feeding, or always formula-fed) with fasting glucose, fasting insulin, and homeostasis model assessment of insulin resistance (HOMA-IR) at 17 years in a subset (n = 710, 8.6% of entire cohort) of the Hong Kong Chinese birth cohort "Children of 1997." We found a graded association of breastfeeding exclusivity in the first 3 months of life with lower fasting insulin and HOMA-IR (p-for-trend < .05), but not fasting glucose, at 17 years. Exclusively breastfed adolescents (7%) had nonsignificantly lowest fasting insulin and HOMA-IR, adjusted for sex, birth weight, parity, length of gestation, pregnancy characteristics, parents' education, and mother's place of birth. Exclusively breastfeeding for 3 months may be causally associated with lower insulin resistance in late adolescence. Further follow-up studies into adulthood are required to clarify the long-term protection of breastfeeding from type 2 diabetes.

Increased Detection of Emergent Recombinant Norovirus GII.P16-GII.2 Strains in Young Adults, Hong Kong, China, 2016-2017.

A new recombinant norovirus GII.P16-GII.2 outnumbered pandemic GII.4 as the predominant GII genotype in the winter of 2016-2017 in Hong Kong, China. Half of hospitalized case-patients were older children and adults, including 13 young adults. This emergent norovirus targets a wider age population compared with circulating pandemic GII.4 strains.

Associations of pubertal stage and body mass index with cardiometabolic risk in Hong Kong Chinese children: A cross-sectional study.

BACKGROUND: Puberty is associated with a clustering of cardiometabolic risk factors (CMRFs) during adolescence that are manifested in later life. Although anthropometric variables such as body mass index (BMI) can predict cardiometabolic risk in children and adolescents, it is not clear whether there is an interaction between pubertal stage and BMI associated with cardiometabolic risk in this age group. This paper examines the association of pubertal stage and BMI with CMRFs in Hong Kong Chinese children. METHODS: A cross-sectional school-based study was conducted among 1985 (95.1%) students aged 6 to 18 years. Fasting lipid profile and plasma glucose, blood pressure, body weight, body height and waist circumference were measured. A self-reported pubertal stage questionnaire was used to assess pubertal stage of participants. Two cardiometabolic risk scores, alpha and beta, were constructed to quantify cardiometabolic risk. Cardiometabolic risk score alpha refers to the sum of z-scores of sex-specific, age-adjusted waist circumference, height-adjusted systolic and diastolic blood pressure, fasting plasma glucose, triglyceride and low-density lipoprotein cholesterol, and minus z-score of sex-specific age-adjusted high-density lipoprotein cholesterol. Cardiometabolic risk score beta includes all components of risk score alpha except waist circumference. RESULTS: The interaction of BMI z-score (ZBMI) and pubertal stage demonstrated a further increase in variance explained in both the cardiometabolic risk scores alpha and beta (0.5% and 0.8% respectively) in boys and (0.7% and 0.5% respectively) in girls. CONCLUSIONS: Pubertal stage has an interaction effect on the association of cardiometabolic risk by BMI in boys and may have a similar but lesser effect in girls.

Online ethnography of breastfeeding discussions in social networking sites for Hong Kong mothers.

With the growth of social networking, parents are increasingly sharing their experiences and opinions or seeking help with childcare through online platforms. This study explored breastfeeding-related topics that Hong Kong mothers raise on social networking sites and how other mothers respond; and how these sites could be a facilitator or barrier to breastfeeding. An online ethnographic approach was used to collect breastfeeding-related discussions (posts and responses) among mothers from three sources: two closed moderated Facebook groups with more than 1000 members, and one open unmoderated forum (Baby Kingdom) (26 December 2021-26 May 2022). Posts not related to breastfeeding (e.g., about formula feeding only) were excluded. Data were collected by a nonparticipatory approach to avoid disrupting the dynamics of the groups. In total, 131 original posts and their 802 responses were collected, of which the common topics discussed were breastfeeding technique, breastfeeding-related health issues, breastfeeding mothers returning to work, and COVID-19 vaccination/infection during breastfeeding. The responses to the queries on breastfeeding technique and health issues in the closed groups were mostly about sharing breastfeeding knowledge and health information to provide timely emotional support and practical solutions. Although similar responses were observed in the open forum, sharing experiences in using formula milk were frequently observed in the responses to posts related to breastfeeding. Social networking sites could be facilitators and barriers to breastfeeding. The potential for infant formula promotion in open forums requires further monitoring and evaluation. Moderation and support from trained professionals or peers could be important.

Influenza B lineage circulation and hospitalization rates in a subtropical city, Hong Kong, 2000-2010.

BACKGROUND: A need for quadrivalent vaccines to cover both lineages of influenza B has been raised. Information on the circulation status of influenza B lineages and the associated hospitalization rates is important to assist evidence-based decision making. This retrospective study revealed the situation in a subtropical city over a 10-year period. METHODS: Sequences of 268 influenza B isolates were analyzed to identify the circulating pool of virus lineages for each year. Hospital records and population census data were used to estimate annual age-specific hospitalization rates. RESULTS: Cocirculation with 2 influenza B lineages was found in 9 of the 10 years. Only in 6 of the 10 years had the vaccine strain successfully matched with the lineage that was found in >50% of the circulating pool. Six years were predominated by one lineage (occupying >80% of the circulating pool), and these years had higher (average, 1.4-fold) hospitalization rates. Matching between vaccine and circulating lineage was achieved only in 2 of the 6 "predominated years." The Yamagata lineage accounted for most (5/6) of the predominated years. Overall, 24% of influenza admissions were due to influenza B, and influenza B contributed to a higher proportion (41.9%) among children and young teenagers (5-14 years old). CONCLUSIONS: Cocirculation with 2 influenza B lineages is common in the subtropical region. To predict the next predominant lineage proves to be difficult. Influenza B accounts for a substantial fraction of influenza-associated hospitalizations, especially among children and young teenagers. Quadrivalent vaccines may improve the effectiveness of influenza vaccination programs.

Rotavirus activity and meteorological variations in an Asian subtropical city, Hong Kong, 1995-2009.

Rotavirus is a leading cause of severe infectious diarrhea in infants and young children aged <5 years. Rotavirus infections have minimal to strong seasonality depending on geographical locations. In this study, a comprehensive retrospective analysis was performed to evaluate the association between rotavirus admission and multiple key meteorological variables, including air temperature, relative humidity, atmospheric pressure, and solar radiation over a 15-year period from 1995 to 2009 in Hong Kong. Rotavirus infections were found to show a distinct cyclical pattern with an annual peak in cold season. The weekly number of cases showed the strongest correlation with average air temperature of the previous 7 days (rho=-0.69; P<0.0001), followed by atmospheric pressure (rho=+0.67; P<0.0001); whereas only weak correlation with relative humidity (rho=-0.252; P<0.0001) and solar radiation (rho=-0.312; P<0.0001) was observed. Curve fitting regression analysis suggested that the correlation was nonlinear in nature in which the effect was more profound towards lower air temperature and higher atmospheric pressure conditions. In binary logistic regression analysis, a final model that included air temperature (≤ 20°C) and atmospheric pressure (≥ 1,013 hPa) predicted correctly 85.3% and 82.6% of weeks with rotavirus activity above and below the baseline level, respectively. In multivariate Poisson model, air temperature and solar radiation were independent factors associated with the weekly number of rotavirus cases, adjusted for seasonal variation. In summary, the current study provides evidence suggesting that local seasonal activity of rotavirus correlated strongly with air temperature, followed by atmospheric pressure but only minimally with relative humidity in pre-vaccine era.

Self-reported body weight and height: an assessment tool for identifying children with overweight/obesity status and cardiometabolic risk factors clustering.

Body mass index (BMI) is commonly used for assessing body fat. Self-reported body weight and height derived BMI (SRDBMI) is a simple, low cost and non-invasive assessment tool and it may be a useful self-reported assessment tool to monitor the prevalence of overweight/obesity in community settings and for epidemiological research. We assessed the agreement of BW and BH between assessor measured and child self-reported values and evaluated the diagnostic ability of SRDBMI to identify children with overweight/obesity status and cardiometabolic risk factors (CMRFs) clustering. A cross-sectional study was conducted in school settings using a cluster sampling method. A total of 1,614 children aged 6-18 years were included in the analysis. Children were given a questionnaire to complete at home prior to the anthropometric measurements and blood taking at the schools. There was almost perfect agreement on BW, BH and BMI between self-reported and measured values [intraclass correlation coefficients ranged from 0.93 (95% CI: 0.93-0.94) to 0.99 (95% CI: 0.98-0.99)]. About half of the children reported their BW and BH absolute values within 1 kg and 2 cm of measured values, respectively. The SRDBMI demonstrated good diagnostic ability for identifying children with overweight/obesity status (sensitivity, specificity, positive and negative predictive values ranged from 0.83 to 0.98) and CMRFs clustering (AUC-ROCs values of BMI between measured and self-reported values were close ranging from 0.85 to 0.89). Self-reported BW and BH demonstrated almost perfect agreement with measured values and could substantially identify children with overweight/obesity status and CMRFs clustering.

Fitness of INTERGROWTH-21st birth weight standards for Chinese-ethnicity babies.

OBJECTIVE: To determine the fitness of the INTERGROWTH-21st birth weight standards (INTERGROWTH21) for ethnic Chinese babies compared with a local reference (FOK2003). DESIGN: Population-based analysis of territory-wide birth data. SETTING: All public hospitals in Hong Kong. PARTICIPANTS: Live births between 24 and 42 complete weeks' gestation during 2006-2017. MAIN OUTCOME MEASURES: Babies' birth weight Z-scores were calculated using published methods. The two references were compared in three aspects: (1) the proportions of large-for-gestational-age (LGA) or small-for-gestational-age (SGA) infants, (2) the gestation-specific and sex-specific mean birth weight Z-scores and (3) the predictive power for SGA-related complications. RESULTS: 488 896 infants were included. Using INTERGROWTH21, among neonates born <33 weeks' gestation, the mean birth weight Z-scores per week were closer to zero (-0.2 to 0.05), while most of them were further from zero (0.06 to 0.34) after excluding infants with a high risk of abnormal intrauterine growth. Compared with FOK2003, INTERGROWTH21 classified smaller proportions of infants as SGA (8.3% vs 9.6%) and LGA (6.6% vs 7.9%), especially SGA among preterm infants (13.1% vs 17.0%). The area under the receiver operating characteristic curve for predicting SGA-related complications was greater with FOK2003 (0.674, 95% CI 0.670 to 0.677) than INTERGROWTH21 (0.658, 95% CI 0.655 to 0.661) (p<0.001). CONCLUSIONS: INTERGROWTH21 performed less well than FOK2003, a local reference for ethnic Chinese babies, especially in infants born <33 weeks' gestation. Although the differences are clinically small, both these references performed poorly for extremely preterm infants, and thus a more robust chart based on a larger sample of appropriately selected infants is needed.

ASVAC2022 : 8th Asian Vaccine Conference.

Aiming to further the Immunization Partners in Asia Pacific (IPAP)'s vision of a world where no one suffers from a vaccine preventable disease, the 8th Asian Vaccine Conference (ASVAC 2022) was held in Colombo, Sri Lanka and virtually from 15 to 18, September 2022 (www.asianvaccine.com). This conference followed those held in Siem Reap, Cambodia (2009), Manila, Philippines (2010), Jakarta, Indonesia (2011), Cebu, Philippines (2013), Hanoi, Vietnam (2015), Singapore (2017) and Naypyidaw and Yangon, Myanmar (2019). The ASVAC2022 themed "Immunization: in Era of Pandemics," commenced with the EPI Managers' Workshop, followed by pre-conference workshops and Vaccinology Masterclass, followed by the main conference featuring 5 plenary lectures, 6 partner-led symposia, free paper and poster presentations, and industry-supported lunch and evening sessions. There were over 1830 registered participants, with 112 attending in person and 998 virtually from 63 countries. The conference was organized by IPAP and hosted by the Vaccine and Infectious Disease Forum of Sri Lanka, Sri Lanka College of Pediatricians, Sri Lanka College of Microbiologists and College of General Practitioners of Sri Lanka, with the support of the Ministry of Health, Sri Lanka. The 9th ASVAC is scheduled to be held in Davao City, Philippines in late 2023.

World variation in head circumference for children from birth to 5 years and a comparison with the WHO standards.

OBJECTIVE: A recent review reported that the WHO 2006 growth standards reflect a smaller head circumference at 24 months than seen in 18 countries. Whether this happens in early infancy and to what extent populations differ is not clear. This scooping review aimed to estimate the rates of children in different populations identified as macrocephalic or microcephalic by WHO standards. METHODS: We reviewed population-representative head circumference-for-age references. For each reference, we calculated the percentages of head circumferences that would be classified as microcephalic (<3rd WHO centile) or macrocephalic (>97th WHO centile) at selected ages. RESULTS: Twelve references from 11 countries/regions (Belgium, China, Ethiopia, Germany, Hong Kong, India, Japan, Norway, Saudi Arabia, UK and USA) were included. Median head circumference was larger than that for the Multicentre Growth Reference Study populations in both sexes in all these populations except for Japanese and Chinese children aged 1 month and Indians. Overall, at 12/24 months, 8%-9% children would be classified as macrocephalic and 2% would be classified as microcephalic, compared with the expected 3%. However at 1 month, there were geographic differences in the rate of macrocephaly (6%-10% in Europe vs 1%-2% in Japan and China) and microcephaly (1%-3% vs 6%-14%, respectively). CONCLUSIONS: Except for Indians and some Asian neonates, adopting the WHO head circumference standards would overdiagnose macrocephaly and underdiagnose microcephaly. Local population-specific cut-offs or references are more appropriate for many populations. There is a need to educate healthcare professionals about the limitations of the WHO head circumference standards.

Inaccurate identification of rotavirus genotype G9 as genotype G3 strains due to primer mismatch.

Reverse transcription (RT)-PCR is now the standard method for typing group A rotaviruses (RVA) to monitor the circulating genotypes in a population. Selection of primers that can accurately type the circulating genotypes is crucial in the context of vaccine introduction and correctly interpreting the impact of vaccination on strain distribution. To our knowledge this study is the first report from Asia of misidentification of genotype G9 as G3 due to a primer-template mismatch. We tested two published G-genotype specific primers sets, designed by Gouvea and colleagues (Set A) and Iturriza-Gomara and colleagues (Set B) on RVA from Hong Kong and Sri Lanka. Among 52 rotaviruses typed as G3 by set A primers, 36 (69.2%) were identified as G9 by nucleotide sequencing and set B primers. Moreover, of 300 rotaviruses tested, 28.3% were untypable by set A primers whereas only 12.3% were untypable by set B primers. Our findings reinforce the need to periodically monitor the primers used for RVA genotyping.

Assessing perceptions of establishing a vaccine pooled procurement mechanism for the Western Pacific Region.

This study explored the demand and interest among countries in the World Health Organization Western Pacific Region (WPR) to establish and participate in a regional vaccine pooled procurement mechanism. National counterparts affiliated with Ministries of Health that are involved in the national procurement of vaccines within the WPR were identified and invited to complete surveys. Out of 80 counterparts invited, 17 (21%) responded, representing 13 of the 27 WPR countries. Five countries expressed interest in participating in a regional pooled procurement mechanism, 3 expressed lack of interest and 5 did not respond to the question. Preferred characteristics of the procurement mechanism, included flexible participation (i.e. non-compulsory), payment in local currency before receipt of goods and a fixed price for vaccines (i.e. not tiered pricing). Vaccine pricing disparities were noted among upper middle-income and high-income countries for five of the 13 routine vaccines surveyed. Eight countries listed budget planning, quality of vaccines, timely delivery, cost-saving and payment after receipt as potential benefits of pooled procurement.

Teleconsultation adoption since COVID-19: Comparison of barriers and facilitators in primary care settings in Hong Kong and the Netherlands.

The COVID-19 pandemic has boosted the adoption of digital health technologies such as teleconsultation. This research aimed to assess and compare barriers and facilitators for teleconsultation uptake for primary care practitioners in Hong Kong and the Netherlands and evaluate the role of their different healthcare funding models in this adoption process within the context of the COVID-19 pandemic. A qualitative research following a social constructivist paradigm was performed. The study employed a conceptual framework from Lau and colleagues that identifies four levels of factors influencing change in primary care: (1) external contextual factors; (2) organization-related factors; (3) professional factors; and (4) characteristics of the intervention. The four levels were studied through semi-structured, open-ended interviews with primary care physicians. External factors were additionally assessed by means of a literature review. Hong Kong and the Netherlands showed different penetration rates of teleconsultation. Most stakeholders in both settings shared similar barriers and facilitators in the organizational, professional, and intervention levels. However, external contextual factors (i.e., current teleconsultation legislation, available incentives, and level of public awareness) played an important and differing role in teleconsultation uptake and had a direct effect on the organization, the professionals involved, and the type of technology used. Political and organizational actions are required to develop a comprehensive legal framework for the sustainable development of teleconsultation in both settings.

Risk factors of non-typhoidal Salmonella gastroenteritis in hospitalised young children: a case-control study.

Objective: To explore risk factors associated with non-typhoidal Salmonella gastroenteritis in young children in Hong Kong. Design: A case-control study. Setting: Paediatrics wards at three public hospitals in Hong Kong. Participants: Cases were children aged above 30 days to below 5 years hospitalised for gastroenteritis at three public hospitals in Hong Kong with culture confirmed non-typhoidal Salmonella infection. Controls were age-matched (±2 months) children admitted for a reason other than gastroenteritis. Main outcomes measures: A face-to-face interview by using standardised questionnaire on exposures 3 days prior to illness. Adjusted OR (aORs) and 95% CIs were calculated using multivariable logistic regression. Results: A total of 102 cases and 204 age-matched controls were included in the analysis. Multivariable logistic regression revealed that having food purchased from places other than a supermarket, that is, from wet market/restaurant/farm (aOR, 2.64; 95% CI, 1.03 to 6.77; p=0.044) was a significant risk factor for non-typhoidal Salmonella infection. Having a household member with gastroenteritis symptoms (aOR, 2.03; 95% CI, 0.94 to 4.39; p=0.072) was of borderline significance and playing at a children's indoor playroom was a protective factor (aOR, 0.28; 95% CI, 0.09 to 0.85; p=0.024). Conclusions: Consumption of food purchased from places other than a supermarket was the identified determinant factor for non-typhoidal Salmonella gastroenteritis in Hong Kong. Parents/caregivers should be alerted to this risk when choosing foods for their young children. The protective effect of playing in an indoor playroom could be confounded by socioeconomic factors and further investigation is required to better understand its potential implication. There was some support for person-to-person transmission and good family hygiene needs to be emphasised.

Feasibility of age- and gestation-based routine universal influenza vaccines schedules for children aged 6 months - 2 years and pregnant women.

BACKGROUND: Hong Kong's seasonal influenza schedule follows the World Health Organization's northern hemisphere vaccine composition recommendations but with year-round influenza activity there is the potential to implement routine age- and gestation-based schedules utilising both northern and southern hemisphere vaccines for children aged 6 months to 2 years and for pregnant women. This study assessed the potential feasibility of such schedules. METHODS: A literature review was conducted and in-depth interviews with vaccine experts, policy makers and nurses were undertaken. RESULTS: The following schedules were proposed and assessed for perceived feasibility: 1) a four-dose schedule in the first two years of life requiring an additional unscheduled clinic visit at 7 months; 2) a three-dose schedule excluding the 4-week booster after the first dose; 3) a two-dose schedule for pregnant women involving a dose at the booking visit and a dose with pertussis vaccine at 7 months gestation; and 4) a one-dose schedule at 7 months gestation. CONCLUSIONS: Age- and gestation-based routine influenza vaccination schedules are theoretically feasible for both young children and pregnant women. The three-dose paediatric and one-dose obstetric schedules were assessed in interviews with vaccine experts, policy makers and nurses to be most acceptable. Further clinical studies are required to determine whether such schedules are non-inferior to current seasonal-based schedules in terms of vaccine effectiveness and vaccine uptake.