Efficacy of COVID-19 Vaccines in Patients with Hematological Malignancy Compared to Healthy Controls: A Systematic Review and Meta-analysis.

Background: The possibility of developing a severe coronavirus infectious (COVID-19) disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has increased, particularly in patients with hematological malignancies. These patients are more likely to produce less antibody protection due to the immunocompromised nature of the disease and the anticancer treatments. Therefore, the present systematic review intended to evaluate the seroconversion rate of COVID-19 vaccines in patients with hematological malignancies compared with healthy controls. Methods: A comprehensive systematic search was conducted in Medline via PubMed, EMBASE, and the World Health Organization COVID-19 Research Database, as well as other searches (i.e., reference list from article search and manual searches), from December 2020 to May 2022. The outcome of interest included estimating the seroconversion rates following COVID-19 vaccination in patients with hematological malignancies and comparing them with those in healthy controls. After two-step screening, the data were extracted and the summary measures were calculated using a random-effects model. Results: A total of 39 articles regarding patients with hematological malignancies were included in the present review. After the first vaccine dose, these patients had considerably lower antibody response rates (37.0%) compared with healthy controls (74.5%). Following the second vaccine dose, the seroconversion rate in patients reached 66.8%, whereas it peaked at 97.9% in the healthy controls following complete immunization. Notably, the BNT162b2 and ChAdOx1 vaccine combination achieved the highest seropositivity rate of approximately 70%. Multiple myeloma, chronic lymphocytic leukemia, and lymphoma were the cancers of interest in most of the studies. Conclusions: The results of the present study highlighted the comparatively low seropositivity rates in patients with hematological malignancies, with substantial variations in rates across disease groups. The findings emphasize the possibility of additional booster doses for these individuals to enhance their immunity against SARS-CoV-2.

Deforestation inhibits malaria transmission in Lao PDR: a spatial epidemiology using Earth observation satellites.

BACKGROUND: The present study aimed to analyze the impact of deforestation on the malaria distribution in the Lao People's Democratic Republic (Lao PDR), with consideration of climate change. METHODS: Malaria distribution data from 2002 to 2015 were obtained from the Ministry of Health of Lao PDR and each indicator was calculated. Earth observation satellite data (forested area, land surface temperature, and precipitation) were obtained from the Japan Aerospace Exploration Agency (JAXA). Structured equation modeling (SEM) was conducted to clarify the relationship between the malaria incidence and Earth observation satellite data. RESULTS: As a result, SEM identified two factors that were independently associated with the malaria incidence: area and proportion of forest. Specifically, malaria was found to be more prevalent in the southern region, with the malaria incidence increasing as the percentage of forested land increased (both p < 0.01). With global warming steadily progressing, forested areas are expected to play an important role in the incidence of malaria in Lao PDR. This is believed because malaria in Lao PDR is mainly forest malaria transmitted by Anopheles dirus. CONCLUSION: To accelerate the elimination of malaria in Lao PDR, it is important to identify, prevent, and intervene in places with increased forest coverage (e.g., plantations) and in low-temperature areas adjacent to malaria-endemic areas, where the vegetation is similar to that in malaria-endemic areas.

Risk Factors Associated with Stunting among Children Under Five in Timor-Leste.

Background: Undernutrition, including stunting, is the cause of almost 45% of all deaths among children under the age of five. It not only affects child growth but also has a long-term negative influence on cognitive and physical abilities. Timor-Leste has the highest prevalence of child stunting in Southeast Asia. Therefore, this study aimed to identify the prevalence of stunting and factors associated with it. Methods: This was a cross-sectional study conducted using the Demographic and Health Survey of 2016 for Timor-Leste. The prevalence of stunting among children under five years of age was examined, and bivariable and multivariable logistic regression analysis was conducted to identify the factors associated with stunting. Results: Among 4,581 children under five years of age, growth in nearly 40% was stunted. The majority of the mothers with stunted children were of age 20-30 years with about 33% having their first baby at ≤19 years of age. Compared to women of <145 cm of height, those of ≥145 cm height had lower likelihood of having a stunted child (OR: 0.62, 95% CI: [0.48-0.80], p < 0.001). It was also interesting to note that the risk of stunting was lower among female children than male children [OR: 0.75, 95% CI: (0.64-0.88), p < 0.001] in our adjusted model. Similarly, other factors such as wealth index, postnatal care visits, currently breastfeeding, age of the child, and size of the child at birth were also associated with stunting. Conclusion: The present findings indicate that child stunting in Timor-Leste is mainly associated with maternal and child sociodemographic status. Hence, it is crucial to identify the quality of services provided by health facilities, the involvement of health workers and volunteers, and the intention of mothers to use the health services in Timor-Leste.

Low Prevalence of Schistosoma mekongi Infection and High Prevalence of Other Helminth Infections among Domestic Animals in Southern Lao People's Democratic Republic.

The prevalence of Schistosoma mekongi in humans in the Lao People's Democratic Republic (Lao PDR) has been relatively well monitored and has decreased due to effective interventions such as preventative chemotherapy with mass drug administration of praziquantel and community awareness programs. However, the prevalence among potential domestic reservoir animals remains broadly unclear, except for a few villages in the endemic area. Therefore, we conducted S. mekongi surveys for the domestic animals that had contact with Mekong River water. We conducted a cross-sectional study of the domestic animals in the seven sentinel villages in the Khong and Mounlapamok Districts of Champasak Province in southern Lao PDR in 2018 by random sampling with a statistically reliable sample size. Stool samples of the five predominant domestic animal species, cattle (n = 160), pig (n = 154), buffalo (n = 149), dog (n = 143), and goat (n = 85), were collected and examined using parasitological FECT method and the LAMP technique. The microscopic analysis did not detect any eggs of S. mekongi in the stool samples of any animal species. However, S. mekongi DNA was detected by the LAMP test in dog stool samples (0.7%; 1/143). On the other hand, the prevalence of other helminths was quite high and heterogeneous among animal species and sentinel sites by the microscopic analysis. These findings suggested that an intervention for S. mekongi infection should focus solely on human populations. However, periodic surveillance for S. mekongi infection among dogs should be conducted to monitor a possible resurgence of S. mekongi infection in the domestic animal population.

Impact of precipitation on the prevalence of schistosomiasis mekongi in Lao PDR: Structural equation modelling using Earth observation satellite data.

Increasing attention is being given to the effect of climate change on schistosomiasis, but the impact is currently unknown. As the intermediate snail host (Neotricula aperta) of Schistosoma mekongi inhabits the Mekong River, it is thought that environmental factors affecting the area of water will have an impact on the occurrence of schistosomiasis mekongi. The aim of the present study was to assess the impact of precipitation on the prevalence of human schistosomiasis mekongi using epidemiological data and Earth observation satellite data in Khong district, Champasak province, Lao PDR. Structural equation modelling (SEM) using epidemiological data and Earth observation satellite data was conducted to determine the factors associated with the number of schistosomiasis mekongi patients. As a result, SEM identified 3 significant factors independently associated with schistosomiasis mekongi: (1) a negative association with mass drug administration (MDA); (2) negative association with total precipitation per year; and (3) positive association with precipitation during the dry season. Precisely, regardless of MDA, the increase in total yearly precipitation was suggested to decrease the number of schistosomiasis patients, whereas an increase in precipitation in the dry season increased the number of schistosomiasis patients. This is probably because when total precipitation increases, the water level of the Mekong River rises, thus decreasing the density of infected larvae, cercaria, in the water, and the frequency of humans entering the river would also decrease. In contrast, when precipitation in the dry season is higher, the water level of the Mekong River also rises, which expands the snail habitant, and thus water contact between humans and the snails would also increase. The present study results suggest that increasing precipitation would impact the prevalence of schistosomiasis both positively and negatively, and precipitation should also be considered in the policy to eliminate schistosomiasis mekongi in Lao PDR.

Detection of Schistosoma mekongi DNA in Human Stool and Intermediate Host Snail Neotricula aperta via Loop-Mediated Isothermal Amplification Assay in Lao PDR.

Schistosomiasis mekongi infection represents a public health concern in Laos and Cambodia. While both countries have made significant progress in disease control over the past few decades, eradication has not yet been achieved. Recently, several studies reported the application of loop-mediated isothermal amplification (LAMP) for detecting Schistosoma DNA in low-transmission settings. The objective of this study was to develop a LAMP assay for Schistosoma mekongi using a simple DNA extraction method. In particular, we evaluated the utility of the LAMP assay for detecting S. mekongi DNA in human stool and snail samples in endemic areas in Laos. We then used the LAMP assay results to develop a risk map for monitoring schistosomiasis mekongi and preventing epidemics. A total of 272 stool samples were collected from villagers on Khon Island in the southern part of Laos in 2016. DNA for LAMP assays was extracted via the hot-alkaline method. Following the Kato-Katz method, we determined that 0.4% (1/272) of the stool samples were positive for S. mekongi eggs, as opposed to 2.9% (8/272) for S. mekongi DNA based on the LAMP assays. Snail samples (n = 11,762) were annually collected along the riverside of Khon Island from 2016 to 2018. DNA was extracted from pooled snails as per the hot-alkaline method. The LAMP assay indicated that the prevalence of S. mekongi in snails was 0.26% in 2016, 0.08% in 2017, and less than 0.03% in 2018. Based on the LAMP assay results, a risk map for schistosomiasis with kernel density estimation was created, and the distribution of positive individuals and snails was consistent. In a subsequent survey of residents, schistosomiasis prevalence among villagers with latrines at home was lower than that among villagers without latrines. This is the first study to develop and evaluate a LAMP assay for S. mekongi detection in stools and snails. Our findings indicate that the LAMP assay is an effective method for monitoring pathogen prevalence and creating risk maps for schistosomiasis.

Factors determining job satisfaction of malaria community microscopists in Palawan, the Philippines: a cross-sectional mixed-methods study.

BACKGROUND: This study was conducted to investigate the overall job satisfaction and its associated factors among microscopists as community health workers who specialize in malaria microscopic diagnosis and treatment in Palawan, the Philippines. The study offered new insights to further lessen the burden of malaria and improve treatment by enhancing their commitment and satisfaction. METHODS: A quantitative study was conducted with 217 microscopists who were asked about their sociodemographic characteristics, ability as microscopists (service quality, knowledge of malaria and ability to diagnose malaria by microscopy [malaria microscopy]) and job satisfaction. Structural equation modelling (SEM) was conducted to analyse these factors. A qualitative study was also conducted and four focus group discussions (FGDs) were carried out. RESULTS: SEM identified that the job satisfaction of microscopists was enhanced by ability in malaria microscopy, the annual parasite index and belonging to ethnic minorities. In the FGDs, high job satisfaction was seen in their devotion to the community and increasing knowledge about malaria. CONCLUSIONS: Providing opportunities to improve malaria microscopy ability would increase the overall job satisfaction of microscopists and eventually improve the quality of care.

Bottom-up approach to strengthen community-based malaria control strategy from community health workers' perceptions of their past, present, and future: a qualitative study in Palawan, Philippines.

BACKGROUND: Microscopists have active roles in bringing malaria diagnosis and treatment closer to households in Palawan, the highest malaria-endemic province in the Philippines. To accelerate the elimination of malaria in Palawan, we performed a study based on the bottom-up approach to provide profound data to strengthen this community-based malaria control from the microscopists' point of view. METHODS: We performed a qualitative cross-sectional study in Palawan. Four focus group discussions with 50 microscopists were conducted in Palawan from November 2010 to February 2011. During the discussions, the following open-ended questions were addressed: motivation for applying to be microscopists in the "Past" category; job satisfaction, role, problems, and saddest and happiest experiences working as microscopists in the "Present" category; and willingness towards task shifting in the "Future" category. Data were transcribed and analyzed by framework analysis using the NVivo software program. RESULTS: The present study innovatively proposed the following strategies: reinforcement strategy (adequate supplies and settings), highly prioritized additional strategies (improving social status of microscopists, issuing a travel budget, and including indigenous populations), regional additional strategies (additional malaria control in the southern region and task shifting in the northern region), and less prioritized additional strategies (employment policy and health checkup). CONCLUSION: A bottom-up approach using microscopists' perceptions would be a valuable method to propose practical and effective additional strategies for strengthening community-based malaria control.

Evaluating active roles of community health workers in accelerating universal access to health services for malaria in Palawan, the Philippines.

BACKGROUND: Palawan is the most malaria-endemic province in the Philippines. In an effort to confront malaria in areas with limited healthcare facilities, microscopists (community health workers) have been trained to diagnose malaria since 1999. METHODS: We reviewed the epidemiological data and related literature which analyzed the achievements of the microscopists and their tasks in order to propose a strategy to strengthen community-based malaria control. RESULTS: The epidemiological data showed that there had been a drastic decrease in malaria morbidity and mortality throughout the province following the launch of the strategy. Microscopists clearly enhanced the feasibility of early diagnosis and treatment throughout the province. However, it remained necessary to implement anti-malarial measures focusing on children under 5 years of age who live in the southern region of the province. The analysis of our published papers also enabled us to propose a new strategy to enhance activities by microscopists to raise malaria awareness in their respective communities. CONCLUSIONS: These low-cost activities are expected to strengthen the preventive measures implemented by the residents and to drive more people to seek appropriate treatment. Consequently, this new strategy could accelerate the efforts to eliminate malaria in the province of Palawan that will be adopted in the WHO's Global Technical Strategy for Malaria 2016-2030, in order to achieve the Sustainable Development Goals by 2030.

Patient Knowledge on Malaria Symptoms Is a Key to Promoting Universal Access of Patients to Effective Malaria Treatment in Palawan, the Philippines.

INTRODUCTION: Palawan, where health care facilities are still limited, is one of the most malaria endemic provinces in the Philippines. Since 1999, microscopists (community health workers) have been trained in malaria diagnosis and feasibility of early diagnosis and treatments have been enhanced throughout the province. To accelerate the universal access of malaria patients to diagnostic testing in Palawan, positive health seeking behavior should be encouraged when malaria infection is suspected. METHODS: In this cross-sectional study, structured interviews were carried out with residents (N = 218) of 20 remote malaria-endemic villages throughout Palawan with a history of suspected malaria from January to February in 2012. Structural equation modeling (SEM) was conducted to determine factors associated with appropriate treatment, which included: (1) socio-demographic characteristics; (2) proximity to a health facility; (3) health seeking behavior; (4) knowledge on malaria; (5) participation in community awareness-raising activities. RESULTS: Three factors independently associated with appropriate treatment were identified by SEM (CMIN = 10.5, df = 11, CFI = 1.000, RMSEA = .000): "living near microscopist" (p < 0.001), "not living near private pharmacy" (p < 0.01), and "having severe symptoms" (p < 0.01). "Severe symptoms" were positively correlated with more "knowledge on malaria symptoms" (p < 0.001). This knowledge was significantly increased by attending "community awareness-raising activities by microscopists" (p < 0.001). CONCLUSIONS: In the resource-limited settings, microscopists played a significant role in providing appropriate treatment to all participants with severe malaria symptoms. However, it was considered that knowledge on malaria symptoms made participants more aware of their symptoms, and further progressed self-triage. Strengthening this recognition sensitivity and making residents aware of nearby microscopists may be the keys to accelerating universal access to effective malaria treatment in Palawan.

Determining the impact of community awareness-raising activities on the prevention of malaria transmission in Palawan, the Philippines.

Palawan has the highest malaria endemicity in the Philippines, and malaria remains a major health burden in the region. In 1999, 344 microscopists were trained in Palawan. This allowed for early diagnosis and prompt treatment throughout the island. To take a significant step toward the elimination of malaria on the island, microscopists implemented community awareness-raising activities aimed at preventing transmission of malaria. The objective of the present study was to determine the impact of these activities on the self-implemented preventive measures against malaria by the ex-patients of the microscopists. Structured interviews were carried out from January to February in 2012, in 20 remote malaria-endemic villages throughout Palawan. In total, 141 ex-patients who had previously been diagnosed malaria-positive by the microscopists, volunteered to participate in the present study. Structural equation modeling was conducted to determine factors associated with self-implemented preventive measures against malaria, which included: (1) place of residence; (2) socio-demographic characteristics; (3) knowledge on malaria; (4) participation in community awareness-raising activities for malaria prevention; and (5) satisfaction with microscopists. Structural equation modeling identified six significant factors independently associated with self-implemented preventive measures against malaria; ethnicity, knowledge on malaria transmission, knowledge on vector species, knowledge on vector's most active time, participation in awareness-raising activities for malaria prevention by microscopists, and satisfaction with microscopists. Tagalog ethnicity (the predominant ethnic group) was positively related to better self-implemented preventive measures. In conclusion, aside from providing early diagnosis and treatment, microscopists played a significant role in self-implemented preventive measures against malaria. The strengthening of awareness-raising activities by microscopists was suggested to be an effective strategy for reducing malaria re-infection in Palawan. These activities should be strengthened to improve preventive measures implemented by ex-patients traveling to mountain areas and to enhance the knowledge on malaria transmission particularly among indigenous residents.

Microsatellite DNA analysis revealed a drastic genetic change of Plasmodium vivax population in the Republic of Korea during 2002 and 2003.

BACKGROUND: Vivax malaria was successfully eliminated in the Republic of Korea (South Korea) in the late 1970s, but it was found to have re-emerged from 1993. In order to control malaria and evaluate the effectiveness of malaria controls, it is important to develop a spatiotemporal understanding of the genetic structure of the parasite population. Here, we estimated the population structure and temporal dynamics of the transmission of Plasmodium vivax in South Korea by analyzing microsatellite DNA markers of the parasite. METHODOLOGY/PRINCIPAL FINDINGS: We analyzed 14 microsatellite DNA loci of the P. vivax genome from 163 South Korean isolates collected from 1994 to 2008. Allelic data were used to analyze linkage disequilibrium (LD), genetic differentiation and population structure, in order to make a detailed estimate of temporal change in the parasite population. The LD analysis showed a gradual decrease in LD levels, while the levels of genetic differentiation between successive years and analysis of the population structure based on the Bayesian approach suggested that a drastic genetic change occurred in the South Korean population during 2002 and 2003. CONCLUSIONS/SIGNIFICANCE: Although relapse and asymptomatic parasite carriage might influence the population structure to some extent, our results suggested the continual introduction of P. vivax into South Korea through other parasite population sources. One possible source, particularly during 2002 and 2003, is North Korea. Molecular epidemiology using microsatellite DNA of the P. vivax population is effective for assessing the population structure and temporal dynamics of parasite transmission; information that can assist in the elimination of vivax malaria in endemic areas.