Jerónimo S. Langa

Mozambique introduced the Rotarix monovalent vaccine (RIX4414 Rotarix^MT) into its childhood immunization schedule in September 2015. We aimed to assess the impact of the vaccine in the prevention of infection and in the diversity of RVA genotypes before and after vaccine introduction. A descriptive cross-sectional study in children under five years of age hospitalized with acute diarrhea in the Pediatric Services of Maputo Central Hospital between 2013 and 2018 was conducted. eight hundred and two stool samples were collected during the pre-vaccination period (2013 - 2015) and 196 in the post-vaccination period (2016 - 2018), where a median reduction of 76% of cases of hospitalization for diarrhea was observed, decreasing from 28.7% (82/284) in the pre-vaccine period to 15.50% (10/66) in the post-vaccination period, (p <0.05) in all age groups. Similarly, there was a median reduction of 53.89% in the proportion of hospitalization for rotavirus diarrhea in children <12 months of age, from (28.29%) in the pre-vaccination period to 13.04% in the post-vaccinal. After the introduction of the vaccine, there was a change in the usual seasonal peaks. The most prevalent combinations of rotavirus genotypes in the pre-vaccine period were G2P[4] in 2013 62/86 (72%), G1P[8] 31/48 (65%) in 2014, G9P[8] 48/70 (69%) in 2015 and in the post - vaccination period were: G1P[8] 5 (50%) in 2016 and 5/8 (62.5%) in 2017; G3P[8], G3P[4], G4P[6] 1/3 (33%) in 2018. After vaccine introduction a reduction of diarrhea hospitalization and rotavirus associated were observed and a wide variety of rotavirus strains circulated in the pre- and post-introduction periods of the vaccine. The results of this study support evidence of the impact of rotavirus vaccination highlighting the importance of program continuity as well as monitoring studies of rotavirus genotypes following the introduction of the vaccine in Mozambique.

Mozambique introduced monovalent rotavirus vaccine (Rotarix^®) in September 2015. We evaluated the effectiveness of Rotarix^® under conditions of routine use in Mozambican children hospitalized with acute gastroenteritis (AGE). A test negative case-control analysis was performed on data collected during 2017–2019 from children <5 years old, admitted with AGE in seven sentinel hospital sites in Mozambique. Adjusted VE was calculated for ≥1 dose of vaccine vs. zero doses using unconditional logistic regression, where VE = (1 − aOR) × 100%. VE estimates were stratified by age group, AGE severity, malnutrition, and genotype. Among 689 children eligible for analysis, 23.7% were rotavirus positive (cases) and 76.3% were negative (controls). The adjusted VE of ≥1 dose in children aged 6–11 months was 52.0% (95% CI, −11, 79), and −24.0% (95% CI, −459, 62) among children aged 12–23 months. Estimated VE was lower in stunted than non-stunted children (14% (95% CI, −138, 66) vs. 59% (95% CI, −125, 91)). Rotavirus vaccination appeared moderately effective against rotavirus gastroenteritis hospitalization in young Mozambican children. VE point estimates were lower in older and stunted children, although confidence intervals were wide and overlapped across strata. These findings provide additional evidence for other high-mortality countries considering rotavirus vaccine introduction.

Diarrhoea is associated with undernutrition and this association is related to increased morbidity and mortality in children under-five. In this analysis we aimed to assess the frequency and associated factors of undernutrition in children under-five with diarrhoea. A hospital-based cross-sectional study was conducted from January 2015 to December 2019 through a surveillance system in five sentinel hospitals in Mozambique. Sociodemographic and clinical information was collected, including anthropometry. A total of 963 children were analysed. The overall undernutrition frequency was 54.1% (95% CI: 50.9–57.2), with 32.5% (95% CI: 29.6–35.5) stunting, 26.6% (95% CI: 23.9–29.6) wasting and 24.7% (95% CI: 22.1–27.5) underweight. Children from Nampula province had 4.7 (p = 0.016) higher odds for stunting compared with children from Maputo. Children whose caregiver was illiterate had higher odds of being underweight 5.24 (p < 0.001), and the wet season was associated with higher odds 1.70 (p = 0.012) of being wasted. Children born under 2500 g of weight had 2.8 (p = 0.001), 2.7 (p < 0.001) and 2.6 (p = 0.010) higher odds for being underweighted, wasted and stunted, respectively. The HIV positive status of the children was associated with higher odds of being underweight 2.6 (p = 0.006), and stunted 3.4 (p = 0.004). The province, caregiver education level, wet season, child’s birthweight and HIV status were factors associated with undernutrition in children with diarrhoea. These findings emphasise the need for additional caregiver’s education on the child’s nutrition and associated infectious diseases. More studies are needed to better understand the social context in which a child with diarrhoea and undernutrition is inserted.

Mozambique introduced the Rotarix^® vaccine (GSK Biologicals, Rixensart, Belgium) into the National Immunization Program in September 2015. Although G1P[8] was one of the most prevalent genotypes between 2012 and 2017 in Mozambique, no complete genomes had been sequenced to date. Here we report whole genome sequence analysis for 36 G1P[8] strains using an Illumina MiSeq platform. All strains exhibited a Wa-like genetic backbone (G1-P[8]-I1-R1-C1-M1-A1-N1-T1-E1-H1). Phylogenetic analysis showed that most of the Mozambican strains clustered closely together in a conserved clade for the entire genome. No distinct clustering for pre- and post-vaccine strains were observed. These findings may suggest no selective pressure by the introduction of the Rotarix^® vaccine in 2015. Two strains (HJM1646 and HGM0544) showed varied clustering for the entire genome, suggesting reassortment, whereas a further strain obtained from a rural area (MAN0033) clustered separately for all gene segments. Bayesian analysis for the VP7 and VP4 encoding gene segments supported the phylogenetic analysis and indicated a possible introduction from India around 2011.7 and 2013.0 for the main Mozambican clade. Continued monitoring of rotavirus strains in the post-vaccine period is required to fully understand the impact of vaccine introduction on the diversity and evolution of rotavirus strains.