Objective: To identify the mosquito species collected in the field of 8 cities/counties of Hainan province, China and to analyze the characteristics of genetic differentiation of the predominant mosquito species. The types, contents and composition characteristics of the midgut microbiota of various mosquito species were explored to provide evidence for the control and prevention of mosquito-borne diseases in Hainan province. Methods: Adult mosquitoes were collected in the field using light traps, human lure or cattle lure methods. Morphology and DNA-barcoding technology (COI gene) were applied to identify the mosquito species. The V3-V4 hypervariable region of microbes 16S rRNA was used for high-throughput sequencing of the midgut microbiota, and SPSS 21.0 and R v3.1.1 software were employed to perform statistical analysis of the sequencing results and the Beta diversity analysis. Results: Aedes (Ae.) albopictus, Armigeres (Ar.) subalbatus and Culex (Cx.) pipiens pallpens were the three predominant species of the mosquito samples. Ae. albopictus was closely related to MK736660 (India) and JQ235749 (Yunnan), while MT541282 (DF, Dongfang) was a relatively independent population. The composition and structure of bacterial communities significantly varied among most of the samples (P<0.05). At the genus levels, 16 genera overlapped in the midgut in Ae. albopictus, 20 in Ar. subalbatus and 26 in Ar. subalbatus. Besides, Ae. albopictus, Ar. subalbatus and Cx. pipiens pallpens shared 15 out of the 16 overlapping genera. Conclusions: Ae. albopictus, Ar. subalbatus and Cx. pipiens pallpens were close within the same species in Hainan. The main exchange of mosquito species occurs within Hainan province, but also occurs across provincial or even national boundaries. The gut microbiota of mosquito species collected from the same sites were similar. Most of the core bacteria found in the midgut of Ae. albopictus were also present in Ar. subalbatus and Cx. pipiens pallpens, indicating that the breeding environment of Ae. albopictus may cover the breeding environment of Ar. subalbatus and Cx. pipiens pallpens.

Objective: To investigate the associations between dietary intakes, eating habits, socioeconomic determinants and malnutrition in children under 5 years old in south China. Method: A case-control study with 182 malnourished (case) and 254 normal (control) children was conducted in four towns using anthropometric measurements and questionnaires. Results: The dietary intakes of calory, protein, vitamin and minerals of malnourished children were lower than their normal counterparts. Overall, 37.9% children ‘monthly or never’ ate egg and egg products, 61.5% ‘monthly or never’ ate beans and soy products, but 76.7% had candies or cakes ‘daily or weekly’. Four identified determinants of malnutrition were: 1) low education level of mother (OR 1.65; 95% CI 1.02-2.67); 2) more children in one family (OR 1.86; 95% CI 1.14-3.03); 3) absence of independent eating habit (OR 1.75; 95% CI 1.13-2.72); and 4) long dining time (≥20 min) (OR 1.91; 95% CI 1.12-3.24). Conclusions: Inadequate dietary intake, lower socioeconomic status and inappropriate eating habits were the major determinants of childhood malnutrition in south China. Nutritional intervention focusing on education and behavior change are warranted to help reduce the rate of malnourishment among the children of rural families in the future.

Objective: To access complete immunization coverage among children aged 18-23 months living in the rural area of Mon State, Myanmar, and study the affecting factors. Methods: A cross-sectional study was conducted in the rural area of Mon State in 2017. Totally 353 caregivers who had children aged 18 to 23 months were selected using multistage random sampling. Face-to-face interview was applied in data collection. Complete immunization status was defined according to the current practice of routine immunization in Myanmar. Chi-square test and multivariate logistic regression analysis were utilized in data analysis. Results: Most of the caregivers were mothers (86.1%). Among 353 children, 293 [83% (95% CI 79.1-86.9)] had been immunized completely. The majority of caregivers had good levels of knowledge (77.1%) and attitude (71.4%) towards routine immunization. Some children (17.6%) had minor adverse events after immunization such as fever, pain and redness at the site of vaccination. Caregivers’ knowledge and attitude towards immunization, and the occurrence of adverse events after immunization in previous immunization session were significantly related to the status of complete immunization coverage (P<0.001). Conclusions: Complete immunization coverage among children living in the rural area of Mon State stands at 83% and should be improved. Health education campaigns with appropriate strategies should be reinforced or strengthened to enhance immunization coverage.

To prevent and control COVID-19, COVID-19 vaccines are being developed, tested, and approved at an unprecedented rate. As of September 24, 2021, 22 types of COVID-19 vaccines have been approved for conditional marketing or emergency use by at least one country worldwide. Vaccine efficacy/effectiveness is a crucial concern for vaccination. This article provides an overview of efficacy of phase III clinical trials, vaccination, effectiveness of real-world studies as well as challenges of COVID-19 vaccine.

According to the statistics of the World Health Organization, malaria is still one of the main diseases affecting human health, especially in Africa, and inflicts a heavy disease burden and a huge economic burden in endemic countries. At present, the widespread emergence of antimalarial drug resistance and unresolved drug availability issues have led researchers to turn their attention to the development of antimalarial vaccines. This review aims at highlighting the recent development of malaria vaccines and discussing the challenges.