Community transmission of rotavirus infection in a vaccinated population in Blantyre, Malawi: a prospective household cohort study

Health economic evaluation of 2-dose and 3-dose rotavirus vaccines in children below 5 years of age in Morocco

Following the introduction of rotavirus vaccination into the Moroccan National Immunization Program, the prevalence of the disease has decreased by nearly 50%. However, evidence on the economic value of rotavirus vaccinations in Morocco is limited. This health economic analysis evaluated, from both country payer and societal perspectives, the costs and the cost-effectiveness of three rotavirus vaccines using a static, deterministic, population model in children aged < 5 years in Morocco. Included vaccines were HRV (2-dose schedule), HBRV (3-dose schedule) and BRV-PV 1-dose vial (3-dose schedule). One-way and probabilistic sensitivity analyses were conducted to assess the impact of uncertainty in model inputs. The model predicted that vaccination with HRV was estimated to result in fewer rotavirus gastroenteritis events (-194 homecare events, -57 medical visits, -8 hospitalizations) versus the 3-dose vaccines, translating into 7 discounted quality-adjusted life years gained over the model time horizon. HRV was associated with lower costs versus HBRV from both the country payer (-$1.8 M) and societal (-$4.1 M) perspectives, and versus BRV-PV 1-dose vial from the societal perspective (-$187,000), dominating those options in the cost-effectiveness analysis. However, costs of BRV-PV 1-dose vial were lower than HRV from the payer perspective, resulting in an ICER of approximately $328,376 per QALY, above the assumed cost effectiveness threshold of $3,500. Vaccination with a 2-dose schedule of HRV may be a cost-saving option and could lead to better health outcomes for children in Morocco versus 3-dose schedule rotavirus vaccines.

Differences in Rotavirus Shedding and Duration by Infant Oral Rotavirus Vaccination Status in Dhaka, Bangladesh, 2011-2014

To evaluate how breakthrough rotavirus disease contributes to transmission, we examined the impact of rotavirus vaccination on fecal shedding and duration of illness. We used multivariable linear regression to analyze rotavirus quantity by RT-qPCR and duration among 184 episodes of rotavirus diarrhea positive by ELISA in the PROVIDE study. Vaccinated children had less fecal viral shedding compared to unvaccinated children (mean difference = -0.59 log copies per gram of stool; 95% confidence interval [CI], -.99 to -.19). Duration of illness was on average 0.47 days (95% CI, -.23 to 1.17 days) shorter among vaccinated children. Rotarix vaccination reduces shedding burden among breakthrough cases of rotavirus gastroenteritis. Clinical Trials Registration . NCT01375647.

Relative abundance and the fate of human rotavirus in wastewater during treatment processes: identification of potential infectious rotavirus in the final effluents and receiving aquatic milieu in Durban area, South Africa

The occurrence and persistence of rotaviruses in raw and treated wastewater and their discharge into rivers represent a significant health risk for humans and animals, worldwide. In this study, samples were collected monthly from each of the four Durban wastewater treatment plants (DWWTPs) and receiving rivers for a period of 3 months. Rotavirus was quantified by real-time quantitative PCR (RT-qPCR), and viability was assessed using integrated cell culture (ICC)-qPCR. Rotavirus was detected consistently in 100% of influent wastewaters (mean concentration range, 4.36-4.46 log10 genome equivalent (GE) copies/L) and final effluent samples of three DWWTPs (range, 3.35-3.61 log10 GE copies/L). Overall, 94% (45/48) of the wastewater analyzed and 95% (20/21) of the associated river water samples were positive for rotavirus (range, 2.04-6.77 log10 GE copies/L). The activated sludge process with 0.10-0.43 log10 reduction values (LRV) only moderately reduced the viral loads. Similarly, one of the DWWTPs that operated the biofilter modality produced 0.20 LRV. Though the additional treatment with chlorine produced higher LRV (range, 0.31-0.53) than the corresponding activated sludge or biofilter process, the difference in viral removals was not significant (p > 0.05). The equivalent treatment efficiencies of the four DWWTPs varied from 19 to 43% decay in the population of rotavirus. Further, infectious rotavirus ranging from 66.67 to 100%, 50 to 100%, and 66.67 to 100% were detected in the post-activated sludge, final effluents, and river water samples, respectively. In conclusion, the findings of infectious rotavirus in both the final effluents and associated rivers represent an infection risk for humans or animals during contact. Thus, close monitoring for rotavirus and risk assessment studies under distinct exposure scenarios may further shed light on the health-related risks associated with water recovery and reuse in urban settings.

Molecular evolutionary analysis of novel NSP4 mono-reassortant G1P[8]-E2 rotavirus strains that caused a discontinuous epidemic in Japan in 2015 and 2018

In the 2010s, several unusual rotavirus strains emerged, causing epidemics worldwide. This study reports a comprehensive molecular epidemiological study of rotaviruses in Japan based on full-genome analysis. From 2014 to 2019, a total of 489 rotavirus-positive stool specimens were identified, and the associated viral genomes were analyzed by next-generation sequencing. The genotype constellations of those strains were classified into nine patterns (G1P[8] (Wa), G1P[8]-E2, G1P[8] (DS-1), G2P[4] (DS-1), G3P[8] (Wa), G3P[8] (DS-1), G8P[8] (DS-1), G9P[8] (Wa), and G9P[8]-E2). The major prevalent genotype differed by year, comprising G8P[8] (DS-1) (37% of that year's isolates) in 2014, G1P[8] (DS-1) (65%) in 2015, G9P[8] (Wa) (72%) in 2016, G3P[8] (DS-1) (66%) in 2017, G1P[8]-E2 (53%) in 2018, and G9P[8] (Wa) (26%) in 2019. The G1P[8]-E2 strains (G1-P[8]-I1-R1-C1-M1-A1-N1-T1-E2-H1) isolated from a total of 42 specimens in discontinuous years (2015 and 2018), which were the newly-emerged NSP4 mono-reassortant strains. Based on the results of the Bayesian evolutionary analyses, G1P[8]-E2 and G9P[8]-E2 were hypothesized to have been generated from distinct independent inter-genogroup reassortment events. The G1 strains detected in this study were classified into multiple clusters, depending on the year of detection. A comparison of the predicted amino acid sequences of the VP7 epitopes revealed that the G1 strains detected in different years encoded VP7 epitopes harboring distinct mutations. These mutations may be responsible for immune escape and annual changes in the prevalent strains.

Epidemiology of Rotavirus in Humans, Animals, and the Environment in Africa: A Systematic Review and Meta-analysis

BACKGROUND

Globally, rotavirus infections are the most common cause of diarrhea-related deaths, especially among children under 5 years of age. This virus can be transmitted through the fecal-oral route, although zoonotic and environmental contributions to transmission are poorly defined. The purpose of this study is to determine the epidemiology of rotavirus in humans, animals, and the environment in Africa, as well as the impact of vaccination.

METHODS

We searched PubMed, Web of Science, Africa Index Medicus, and African Journal Online, identifying 240 prevalence data points from 224 articles between 2009 and 2022.

RESULTS

Human rotavirus prevalence among patients with gastroenteritis was 29.8% (95% confidence interval [CI], 28.1%-31.5%; 238 710 participants), with similar estimates in children under 5 years of age, and an estimated case fatality rate of 1.2% (95% CI, .7%-2.0%; 10 440 participants). Prevalence was estimated to be 15.4% and 6.1% in patients with nongastroenteritis illnesses and apparently healthy individuals, respectively. Among animals, prevalence was 9.3% (95% CI, 5.7%-13.7%; 6115 animals), and in the environmental water sources, prevalence was 31.4% (95% CI, 17.7%-46.9%; 2530 samples).

DISCUSSION

Our findings highlight the significant burden of rotavirus infection in Africa, and underscore the need for a One Health approach to limiting the spread of this disease.

Infectious Diarrhea Risks as a Public Health Emergency in Floods; a Systematic Review and Meta-Analysis

Introduction

Infectious diarrhea, a significant global health challenge, is exacerbated by flooding, a consequence of climate change and environmental disruption. This comprehensive study aims to quantify the association between flooding events and the incidence of infectious diarrhea, considering diverse demographic, environmental, and pathogen-specific factors.

Methods

In this systematic review and meta-analysis, adhering to PROSPERO protocol (CRD42024498899), we evaluated observational studies from January 2000 to December 2023. The analysis incorporated global data from PubMed, Scopus, Embase, Web of Science, and ProQuest, focusing on the relative risk (RR) of diarrhea post-flooding. The study encompassed diverse variables like age, sex, pathogen type, environmental context, and statistical modeling approaches.

Results

The meta-analysis, involving 42 high-quality studies, revealed a substantial increase (RR = 1.40, 95% CI [1.29-1.52]) in the incidence of diarrhea following floods. Notably, bacterial and parasitic diarrheas demonstrated higher RRs (1.82 and 1.35, respectively) compared to viral etiologies (RR = 1.15). A significant sex disparity was observed, with women exhibiting a higher susceptibility (RR = 1.55) than men (RR = 1.35). Adults (over 15 years) faced a greater risk than younger individuals, highlighting age-dependent vulnerability.

Conclusion

This extensive analysis confirms a significant correlation between flood events and increased infectious diarrhea risk, varying across pathogens and demographic groups. The findings highlight an urgent need for tailored public health interventions in flood-prone areas, focusing on enhanced sanitation, disease surveillance, and targeted education to mitigate this elevated risk. Our study underscores the critical importance of integrating flood-related health risks into global public health planning and climate change adaptation strategies.

Prevalence of Cryptosporidium and Giardia infections in under-five children with diarrhoea in Blantyre, Malawi

BACKGROUND

Diarrhoeal diseases are common among children in low- and middle-income countries and are major causes of morbidity and mortality. Cryptosporidium and Giardia are considered to be the main parasitic causes of diarrhoea in children. The aim of the present study was to determine the prevalence and associated factors of Cryptosporidium and Giardia infection in children under five years of age presenting at two health centres (Ndirande and Limbe) in Blantyre, Malawi.

METHODS

This cross-sectional study was performed from February to July 2019 and included 972 children under 5 years of age with diarrhoea. Stool samples were immediately tested after collection at enrolment with a rapid diagnostic test for Cryptosporidium and Giardia infection. Descriptive statistics were used to assess the prevalence of these protozoan parasitic infections, and differences in the basic demographic and anthroponotic variables (between children with diarrhoea and parasite infection, being either Cryptosporidium and Giardia or both versus children with diarrhoea but no RDT confirmed parasite infection) were assessed. Their association with Cryptosporidium and Giardia infection was analysed using simple logistic regressions.

RESULTS

Of the children recruited, 88 (9.1%) tested positive for Cryptosporidium and 184 (18.9%) for Giardia. Children with only a Giardia infection or a coinfection (of both parasites) were significantly older (mean age 24-26 months) compared to children with only a Cryptosporidium infection (mean age 13 months) or no parasitic infection (mean age 14 months). No significant differences were found with respect to gender, body temperature, stunting or wasting between the different groups of children with moderate to severe diarrhoea. Children attending the Ndirande health centre had almost two times higher odds of testing positive for both infections than those attending Limbe health centre.

CONCLUSION

Cryptosporidium and Giardia infections are highly prevalent in children < 5 years with moderate to severe diarrhoea attending the Limbe and Ndirande health centres in Blantyre, Malawi.

Effect of 13-valent pneumococcal conjugate vaccine on experimental carriage of Streptococcus pneumoniae serotype 6B in Blantyre, Malawi: a randomised controlled trial and controlled human infection study

BACKGROUND

The effect of childhood pneumococcal conjugate vaccine implementation in Malawi is threatened by absence of herd effect. There is persistent vaccine-type pneumococcal carriage in both vaccinated children and the wider community. We aimed to use a human infection study to measure 13-valent pneumococcal conjugate vaccine (PCV13) efficacy against pneumococcal carriage.

METHODS

We did a double-blind, parallel-arm, randomised controlled trial investigating the efficacy of PCV13 or placebo against experimental pneumococcal carriage of Streptococcus pneumoniae serotype 6B (strain BHN418) among healthy adults (aged 18-40 years) from Blantyre, Malawi. We randomly assigned participants (1:1) to receive PCV13 or placebo. PCV13 and placebo doses were prepared by an unmasked pharmacist to maintain research team and participant masking with identification only by a randomisation identification number and barcode. 4 weeks after receiving either PCV13 or placebo, participants were challenged with 20 000 colony forming units (CFUs) per naris, 80 000 CFUs per naris, or 160 000 CFUs per naris by intranasal inoculation. The primary endpoint was experimental pneumococcal carriage, established by culture of nasal wash at 2, 7, and 14 days. Vaccine efficacy was estimated per protocol by means of a log-binomial model adjusting for inoculation dose. The trial is registered with the Pan African Clinical Trials Registry, PACTR202008503507113, and is now closed.

FINDINGS

Recruitment commenced on April 27, 2021 and the final visit was completed on Sept 12, 2022. 204 participants completed the study protocol (98 PCV13, 106 placebo). There were lower carriage rates in the vaccine group at all three inoculation doses (0 of 21 vs two [11%] of 19 at 20 000 CFUs per naris; six [18%] of 33 vs 12 [29%] of 41 at 80 000 CFUs per naris, and four [9%] of 44 vs 16 [35%] of 46 at 160 000 CFUs per naris). The overall carriage rate was lower in the vaccine group compared with the placebo group (ten [10%] of 98 vs 30 [28%] of 106; Fisher's p value=0·0013) and the vaccine efficacy against carriage was estimated at 62·4% (95% CI 27·7-80·4). There were no severe adverse events related to vaccination or inoculation of pneumococci.

INTERPRETATION

This is, to our knowledge, the first human challenge study to test the efficacy of a pneumococcal vaccine against pneumococcal carriage in Africa, which can now be used to establish vaccine-induced correlates of protection and compare alternative strategies to prevent pneumococcal carriage. This powerful tool could lead to new means to enhance reduction in pneumococcal carriage after vaccination.

FUNDING

Wellcome Trust.

Comparative whole genome analysis reveals re-emergence of human Wa-like and DS-1-like G3 rotaviruses after Rotarix vaccine introduction in Malawi

G3 rotaviruses rank among the most common rotavirus strains worldwide in humans and animals. However, despite a robust long-term rotavirus surveillance system from 1997 at Queen Elizabeth Central Hospital in Blantyre, Malawi, these strains were only detected from 1997 to 1999 and then disappeared and re-emerged in 2017, 5 years after the introduction of the Rotarix rotavirus vaccine. Here, we analysed representative twenty-seven whole genome sequences (G3P[4], n = 20; G3P[6], n = 1; and G3P[8], n = 6) randomly selected each month between November 2017 and August 2019 to understand how G3 strains re-emerged in Malawi. We found four genotype constellations that were associated with the emergent G3 strains and co-circulated in Malawi post-Rotarix vaccine introduction: G3P[4] and G3P[6] strains with the DS-1-like genetic backbone genes (G3-P[4]-I2-R2-C2-M2-A2-N2-T2-E2-H2 and G3-P[6]-I2-R2-C2-M2-A2-N2-T2-E2-H2), G3P[8] strains with the Wa-like genetic backbone genes (G3-P[8]-I1-R1-C1-M1-A1-N1-T1-E1-H1), and reassortant G3P[4] strains consisting of the DS-1-like genetic backbone genes and a Wa-like NSP2 (N1) gene (G3-P[4]-I2-R2-C2-M2-A2-N1-T2-E2-H2). Time-resolved phylogenetic trees demonstrated that the most recent common ancestor for each ribonucleic acid (RNA) segment of the emergent G3 strains was between 1996 and 2012, possibly through introductions from outside the country due to the limited genetic similarity with G3 strains which circulated before their disappearance in the late 1990s. Further genomic analysis revealed that the reassortant DS-1-like G3P[4] strains acquired a Wa-like NSP2 genome segment (N1 genotype) through intergenogroup reassortment; an artiodactyl-like VP3 through intergenogroup interspecies reassortment; and VP6, NSP1, and NSP4 segments through intragenogroup reassortment likely before importation into Malawi. Additionally, the emergent G3 strains contain amino acid substitutions within the antigenic regions of the VP4 proteins which could potentially impact the binding of rotavirus vaccine-induced antibodies. Altogether, our findings show that multiple strains with either Wa-like or DS-1-like genotype constellations have driven the re-emergence of G3 strains. The findings also highlight the role of human mobility and genome reassortment events in the cross-border dissemination and evolution of rotavirus strains in Malawi necessitating the need for long-term genomic surveillance of rotavirus in high disease-burden settings to inform disease prevention and control.

Model-based estimation of the impact on rotavirus disease of RV3-BB vaccine administered in a neonatal or infant schedule

Rotavirus infection is a common cause of severe diarrheal disease and a major cause of deaths and hospitalizations among young children. Incidence of rotavirus has declined globally with increasing vaccine coverage. However, it remains a significant cause of morbidity and mortality in low-income countries where vaccine access is limited and efficacy is lower. The oral human neonatal vaccine RV3-BB can be safely administered earlier than other vaccines, and recent trials in Indonesia have demonstrated high efficacy. In this study, we use a stochastic individual-based model of rotavirus transmission and disease to estimate the anticipated population-level impact of RV3-BB following delivery according to either an infant (2, 4, 6 months) and neonatal (0, 2, 4 months) schedule. Using our model, which incorporated an age- and household-structured population and estimates of vaccine efficacy derived from trial data, we found both delivery schedules to be effective at reducing infection and disease. We estimated 95-96% reductions in infection and disease in children under 12 months of age when vaccine coverage is 85%. We also estimate high levels of indirect protection from vaccination, including 78% reductions in infection in adults over 17 years of age. Even for lower vaccine coverage of 55%, we estimate reductions of 84% in infection and disease in children under 12 months of age. While open questions remain about the drivers of observed lower efficacy in low-income settings, our model suggests RV3-BB could be effective at reducing infection and preventing disease in young infants at the population level.

Rotavirus vaccines: progress and new developments

INTRODUCTION

Rotavirus is the primary cause of severe acute gastroenteritis among children under the age of five globally, leading to 128,500 to 215,000 vaccine-preventable deaths annually. There are six licensed oral, live-attenuated rotavirus vaccines: four vaccines pre-qualified for global use by WHO, and two country-specific vaccines. Expansion of rotavirus vaccines into national immunization programs worldwide has led to a 59% decrease in rotavirus hospitalizations and 36% decrease in diarrhea deaths due to rotavirus in vaccine-introducing countries.

AREAS COVERED

This review describes the current rotavirus vaccines in use, global coverage, vaccine efficacy from clinical trials, and vaccine effectiveness and impact from post-licensure evaluations. Vaccine safety, particularly as it relates to the risk of intussusception, is also summarized. Additionally, an overview of candidate vaccines in the pipeline is provided.

EXPERT OPINION

Considerable evidence over the past decade has demonstrated high effectiveness (80-90%) of rotavirus vaccines at preventing severe rotavirus disease in high-income countries, although the effectiveness has been lower (40-70%) in low-to-middle-income countries. Surveillance and research should continue to explore modifiable factors that influence vaccine effectiveness, strengthen data to better evaluate newer rotavirus vaccines, and aid in the development of future vaccines that can overcome the limitations of current vaccines.

Reduction in Severity of All-Cause Gastroenteritis Requiring Hospitalisation in Children Vaccinated against Rotavirus in Malawi

Rotavirus is the major cause of severe gastroenteritis in children aged <5 years. Introduction of the G1P[8] Rotarix® rotavirus vaccine in Malawi in 2012 has reduced rotavirus-associated hospitalisations and diarrhoeal mortality. However, the impact of rotavirus vaccine on the severity of gastroenteritis presented in children requiring hospitalisation remains unknown. We conducted a hospital-based surveillance study to assess the impact of Rotarix® vaccination on the severity of gastroenteritis presented by Malawian children. Stool samples were collected from children aged <5 years who required hospitalisation with acute gastroenteritis from December 2011 to October 2019. Gastroenteritis severity was determined using Ruuska and Vesikari scores. Rotavirus was detected using enzyme immunoassay. Rotavirus genotypes were determined using nested RT-PCR. Associations between Rotarix® vaccination and gastroenteritis severity were investigated using adjusted linear regression. In total, 3159 children were enrolled. After adjusting for mid-upper arm circumference (MUAC), age, gender and receipt of other vaccines, all-cause gastroenteritis severity scores were 2.21 units lower (p < 0.001) among Rotarix®-vaccinated (n = 2224) compared to Rotarix®-unvaccinated children (n = 935). The reduction in severity score was observed against every rotavirus genotype, although the magnitude was smaller among those infected with G12P[6] compared to the remaining genotypes (p = 0.011). Each one-year increment in age was associated with a decrease of 0.43 severity score (p < 0.001). Our findings provide additional evidence on the impact of Rotarix® in Malawi, lending further support to Malawi's Rotarix® programme.

The Government's Involvement in Prenatal Drug Testing May Be Toxic

In 25 U.S. states, healthcare professionals are mandated to report pregnant people for substance use to child protection service (CPS) agencies. This practice is not evidence-based, and we believe it harms the patient-provider relationship, opposes reproductive autonomy, and contributes to racial disparities in CPS referrals and their outcomes. Black patients are more often screened and reported than white patients for prenatal substance use; besides the impact on their obstetric care, this may be a barrier to seeking treatment for substance use disorders. Furthermore, strict, punitive state-level policies are associated with greater odds of neonatal abstinence syndrome. The treatment of substance use disorders in pregnancy under the Child Abuse Prevention and Treatment Act opposes robust evidence understanding substance use disorders as chronic illnesses. Among non-pregnant people seeking healthcare, substance use is not a "reportable offense." This double marginalization of pregnant patients limits their autonomy and unduly exposes them to the criminal-legal system. Given disparities in prenatal drug screening, Black pregnant patients are at greater risk of such double-jeopardy. Public health and medical organizations have released policy statements against states' punitive laws, but little has changed. Healthcare providers and institutions should prioritize evidence-based care to benefit the health and wellbeing of birthing person and their infant and combat "legal" interference at the clinic and public-health scale.

Short-Term Changes in Behaviors Resulting from COVID-19-Related Social Isolation and Their Influences on Mental Health in Ghana

This study assessed the behavioral outcomes of Coronavirus 2019 (COVID-19) social distancing protocols and their influences on mental health. An online survey hosted by Survey Monkey was utilized to collect data from residents of three Ghanaian cities of Accra, Kumasi and Tamale. A total of 621 surveys were analyzed, with a sensitivity analysis utilized to select covariates for the regression model. The average age of participants was about 36 years. Findings indicate that reduced physical activity time and a change in sexual activity and smoking frequency are some short-term changes in behavior resulting from social isolation during the lockdown. An increase in sedentary behavior had a negative influence on mental health. For the most part, changes in behaviors in the short-term were associated with lower mental health scores. The study implied that COVID-19 social distancing measures should be implemented alongside public education for discouraging unhealthy changes in behaviors.