Rotavirus A infection in children under five years old with a double health problem: undernutrition and diarrhoea - a cross-sectional study in four provinces of Mozambique.

BACKGROUND: Mozambique has a high burden of group A rotavirus (RVA) infection and chronic undernutrition. This study aimed to determine the frequency and potential risk factors for RVA infection in undernourished children under 5 years old with diarrhoea in Mozambique. METHODS: The analysis was conducted using data from March 2015 to December 2017, regarding children under 5 years old with at least one type of undernutrition. Anthropometric measures were used to calculate indices of weight-for-age, weight-for-height and height-for-age through the Z-Scores. RVA results were extracted from the National Diarrhoea Surveillance database. Descriptive statistics, chi-square test was used for qualitative variables and organized in contingency tables and 95% Confidence Intervals (CI) were considered for the calculation of RVA infection proportion and in the multiple logistic regression models to estimate the adjusted odds ratios (AOR). RESULTS: Of the 842 undernourished children included in the analysis, 27.2% (95% CI: 24.3-30.3%) were positive for RVA. The rate of RVA infection was 42.7% (95% CI: 38.0-47.5%) in the pre-vaccine period, with great reduction to 12.2% (95% CI: 9.4-15.6%) in the post-vaccine period. Most of the RVA undernourished children had severe wasting (33.3%) and severe stunting (32.0%). The risk of infection was significantly high in children from 0 to 11 months (p-value < 0.001) when compared to the age group of 24-59 months. A higher proportion of RVA infection was detected in households with five or more members (p-value = 0.029). Similar proportions of RVA were observed in children fed only by breast milk (34.9%) and breast milk with formula (35.6%). A higher proportion of undernourished HIV-positive children co-infected with RVA (7.4%) was observed. CONCLUSIONS: The frequency of RVA infection in undernourished children declined following the introduction of the vaccine in Mozambique. Beyond the temporal variation, Maputo province, age and crowded households were also associated to RVA infection. A high proportion of RVA infection was observed in children with severe wasting and a triple burden of disease: undernutrition, RVA and HIV, highlighting the need to conduct follow-up studies to understand the long-term impact of these conditions on children's development.

Whole-genome characterization of G12 rotavirus strains detected in Mozambique reveals a co-infection with a GXP[14] strain of possible animal origin.

A high prevalence of G12 rotavirus strains has previously been reported in southern Mozambique. In this study, the full genomes of five Mozambican G12 strains were determined directly from stool using an Illumina Miseq platform. One sample (0060) contained an intergenogroup co-infection of a G12P[8] Wa-like strain and a GXP[14] DS-1-like strain. The sequences of seven genome segments, detected for the GXP[14] strain, clustered with a diverse group of mostly animal strains, suggesting co-infection with a strain of possible animal origin. The stool samples contained G12P[6] rotavirus strains with Wa-like backbones. Phylogenetic analyses of the VP4 and VP7 encoding segments of the G12P[6] strains suggested that they were reassortants containing backbones that are similar to that of the G12P[8] strain. The study confirms previous observations of interspecies transmission and emphasizes the importance of whole-genome sequencing in order to evaluate rotavirus co-infections and reassortants.

Rotavirus A strains obtained from children with acute gastroenteritis in Mozambique, 2012-2013: G and P genotypes and phylogenetic analysis of VP7 and partial VP4 genes.

In Mozambique rotavirus (RV) was shown to be the greatest cause of acute diarrhoea in infants from 0 to 11 months, and in 2015, national rotavirus vaccination was introduced. As with other developing countries, there is very limited active strain characterisation. Rotavirus positive clinical specimens, collected between 2012 and 2013, have now provided information on the genotypes circulating in southern Mozambique prior to vaccine introduction. Genotypes G2 (32.4%), G12 (28.0%), P[4] (41.4%) and P[6] (22.9%) (n = 157) strains were commonly detected with G2P[4] (42.3%) RVs being predominant, specifically during 2013. Phylogenetic evaluation of the VP7 and VP8* encoding genes showed, for the majority of the Mozambican strains, that they clustered with other African strains based on genotype. RVA/Human-wt/MOZ/0153/2013/G2P[4], RVA/Human-wt/MOZ/0308/2012/G2P[4] and RVA/Human-wt/MOZ/0288/2012/G12P[8] formed separate clusters from the other Mozambican strains with similar genotypes, suggesting possible reassortment. Amino acid substitutions in selected epitope regions also supported phylogenetic clustering. As expected, the VP7 and VP8* genes from the Mozambican strains differed from both the RotaTeq® (SC2-9) G2P[5] and Rotarix® (A41CB052A) G1P[8] genes. This study provides information on the genetic diversity of rotavirus strains prior to vaccine introduction and generates baseline data for future monitoring of any changes in rotavirus strains in response to vaccine pressure.

Rotavirus A infection in pre- and post-vaccine period: Risk factors, genotypes distribution by vaccination status and age of children in Nampula Province, Northern Mozambique (2015-2019).

Mozambique introduced the monovalent rotavirus vaccine (Rotarix®, GSK Biologicals, Rixensart, Belgium) in September 2015. Previous analysis, showed that Nampula province continues reporting a high frequency of Rotavirus A (RVA) infection and the emergence of G9P[6], G9P[4] and G3P[4] genotypes. This analysis aimed to determine the RVA frequency; risk factors; genotype distribution by vaccination status and age between pre- and post-vaccine periods in children under-five years old with diarrhea in Nampula. A cross-sectional, hospital-based surveillance study was conducted in the Hospital Central de Nampula in Mozambique. Socio-demographic and clinical data were collected to assess factors related to RVA infection in both periods. Stool specimens were screened to detect RVA by ELISA, and positive samples were genotyped. Between 2015 (pre-vaccine period) and 2016-2019 (post-vaccine period), 614 stool specimens were collected and tested for RVA in which 34.9% (67/192) were positive in pre-vaccine period and 21.8% (92/422) in post-vaccine (p = 0.001). In the post-vaccine period, age, year, and contact with different animal species (chicken, duck, or multiple animals) were associated with RVA infection. RVA infection was higher in children partially vaccinated (40.7%, 11/27) followed by the fully vaccinated (29.3%, 56/191) and the unvaccinated (15.3%, 21/137) (p = 0.002). G1P[8] and G9P[4] were common in vaccinated children less than 12 months. The present analysis showed that RVA infection reduced slightly in the post-vaccine period, with a high proportion of infection and genotype diversity in children, under 12 months of age, vaccinated. Further research on factors associated with RVA infection on vaccinated compared to unvaccinated children and vaccination optimization should be done.

Whole genome analyses of DS-1-like Rotavirus A strains detected in children with acute diarrhoea in southern Mozambique suggest several reassortment events.

We report the first whole genome constellations of Mozambican rotavirus A strains detected between 2012 and 2013 in the Mavalane General Hospital in Maputo city and Manhiça District Hospital in the Manhiça district. Consensus sequences for ten DS-1-like strains (G2P[4] and G8P[4]) were identified with an Illumina Miseq platform using cDNA prepared from dsRNA extracted from stool samples, without genome amplification or prior adaptation to cell culture. Comparison of previously reported genotyping results and the consensus sequences described in this study, indicated that the genotype primers specific for G12 and P[4] might require revision. Phylogenetic analyses indicated diversity among the G2P[4] Mozambican strains and suggested reassortment between G2P[4] and G8P[4] Mozambican strains, as well as the intragenogroup reassortment of all the genome segments encoding VP1, 2, 3 and 6 for strain RVA/Human-wt/MOZ/0045/2012G8P[4]. These results highlight the necessity to determine whole genome constellations to confirm surveillance data in Africa and to monitor the growing diversity in DS-1-like strains.

Early impact of rotavirus vaccination in children less than five years of age in Mozambique.

BACKGROUND: Mozambique introduced rotavirus vaccine (Rotarix, GSK Biologicals) in the National Immunization Program in September 2015 with the objective of reducing the burden of total diarrheal disease and specifically severe rotavirus disease. This study aimed to evaluate the early impact of rotavirus vaccine in reducing all-cause diarrhea and rotavirus-specific hospitalizations. METHODS: We analysed stool specimens collected from children under five years old, between January 2014 and June 2017 within the National Surveillance for Acute Diarrhea. We compared annual changes in rotavirus positivity, median age of children hospitalized for rotavirus and the number of all-cause for diarrheal hospitalizations. Rotavirus detection was performed using enzyme immunoassay. RESULTS: During this period, 1296 samples were collected and analyzed. Rotavirus positivity before vaccine introduction was 40.2% (39/97) in 2014 and 38.3% (225/588) in 2015, then after vaccine introduction reduced to 12.2% and 13.5% in 2016 and 2017, respectively. The median age of children hospitalized for rotavirus was 9 and 11 months in 2014 and 2015 and 10 months in 2016 and 2017. Rotavirus hospitalizations exhibited a seasonal peak prior to vaccine introduction, between June and September in 2014 and 2015, coinciding with winter period in Mozambique. After vaccine introduction, the peak was delayed until August to December in 2016 and was substantially diminished. There was a reduction in all-cause acute diarrhea hospitalizations in children aged 0-11 months after vaccine introduction. CONCLUSION: We observed a reduction in rotavirus positivity and in the number of all-cause diarrhea hospitalizations after vaccine introduction. The data suggest rotavirus vaccine is having a positive impact on the control of rotavirus diarrheal disease in Mozambique.