Daniel Hungerford1, Khuzwayo C Jere2, Naor Bar-Zeev3, John P Harris4, Nigel A Cunliffe5, Miren Iturriza-Gómara6. 1. Centre for Global Vaccine Research, Institute of Infection and Global Health, University of Liverpool, Members of Liverpool Health Partners, Ronald Ross Building, 8 West Derby Street, Liverpool, L69 7BE, UK; NIHR, Health Protection Research Unit in Gastrointestinal Infections at University of Liverpool, L69 3GL, Liverpool, United Kingdom. Electronic address: d.hungerford@liverpool.ac.uk. 2. Centre for Global Vaccine Research, Institute of Infection and Global Health, University of Liverpool, Members of Liverpool Health Partners, Ronald Ross Building, 8 West Derby Street, Liverpool, L69 7BE, UK; Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi; Department of Medical Laboratory Sciences, College of Medicine, University of Malawi, Blantyre, Malawi. 3. Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi; International Vaccine Access Center, Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, USA. 4. NIHR, Health Protection Research Unit in Gastrointestinal Infections at University of Liverpool, L69 3GL, Liverpool, United Kingdom. 5. Centre for Global Vaccine Research, Institute of Infection and Global Health, University of Liverpool, Members of Liverpool Health Partners, Ronald Ross Building, 8 West Derby Street, Liverpool, L69 7BE, UK. 6. Centre for Global Vaccine Research, Institute of Infection and Global Health, University of Liverpool, Members of Liverpool Health Partners, Ronald Ross Building, 8 West Derby Street, Liverpool, L69 7BE, UK; NIHR, Health Protection Research Unit in Gastrointestinal Infections at University of Liverpool, L69 3GL, Liverpool, United Kingdom.
Abstract
BACKGROUND: Following rotavirus vaccine introduction, norovirus has emerged as a significant pathogen associated with acute gastroenteritis among children in some high- and middle-income countries. In a case-control study following rotavirus vaccination in Malawi, we used PCR to test for multiple enteric pathogens in fecal samples from children aged <5 years hospitalized with diarrhea, and from asymptomatic community controls (Iturriza-Gómara et al. 2019). OBJECTIVES: To describe the epidemiology and genotype diversity of norovirus infections among infants and young children in Blantyre, Malawi, following rotavirus vaccine introduction in 2012. STUDY DESIGN: We analysed data from the case-control study to assess annual and agespecific norovirus prevalence and the presence of co-infection. Norovirus-containing specimens were amplified by PCR and sequenced to determined genotype. RESULTS: Norovirus prevalence in cases was similar for each complete year of study (11.4% in 2013, 9.3% in 2014 and 11.2% in 2015). Prevalence of norovirus among children aged <6 months, 6-11 months, 12-23 months and 24+ months was 15.3% (11/72), 13.3% (44/331), 11.0% (24/219) and 6.6% (4/61) respectively in cases and 6.7% (2/30), 13.1% (30/229), 4.2% (8/192) and 7.1 (5/70) in controls. Co-pathogens were commonly detected in norovirus positive cases (77/83) and controls (44/45). Norovirus GII.4 was the most commonly identified genotype, comprising 48% and 41% of genotyped strains among cases and controls, respectively. CONCLUSIONS: Norovirus disease prevalence was unchanged during the study period, and was greatest amongst infants. Frequent co-infection and asymptomatic shedding suggests intense community transmission of norovirus and other enteric pathogens in this low-income, African setting.
BACKGROUND: Following rotavirus vaccine introduction, norovirus has emerged as a significant pathogen associated with acute gastroenteritis among children in some high- and middle-income countries. In a case-control study following rotavirus vaccination in Malawi, we used PCR to test for multiple enteric pathogens in fecal samples from children aged <5 years hospitalized with diarrhea, and from asymptomatic community controls (Iturriza-Gómara et al. 2019). OBJECTIVES: To describe the epidemiology and genotype diversity of norovirus infections among infants and young children in Blantyre, Malawi, following rotavirus vaccine introduction in 2012. STUDY DESIGN: We analysed data from the case-control study to assess annual and agespecific norovirus prevalence and the presence of co-infection. Norovirus-containing specimens were amplified by PCR and sequenced to determined genotype. RESULTS:Norovirus prevalence in cases was similar for each complete year of study (11.4% in 2013, 9.3% in 2014 and 11.2% in 2015). Prevalence of norovirus among children aged <6 months, 6-11 months, 12-23 months and 24+ months was 15.3% (11/72), 13.3% (44/331), 11.0% (24/219) and 6.6% (4/61) respectively in cases and 6.7% (2/30), 13.1% (30/229), 4.2% (8/192) and 7.1 (5/70) in controls. Co-pathogens were commonly detected in norovirus positive cases (77/83) and controls (44/45). Norovirus GII.4 was the most commonly identified genotype, comprising 48% and 41% of genotyped strains among cases and controls, respectively. CONCLUSIONS:Norovirus disease prevalence was unchanged during the study period, and was greatest amongst infants. Frequent co-infection and asymptomatic shedding suggests intense community transmission of norovirus and other enteric pathogens in this low-income, African setting.
Authors: Chimwemwe Mhango; Jonathan J Mandolo; End Chinyama; Richard Wachepa; Oscar Kanjerwa; Chikondi Malamba-Banda; Prisca B Matambo; Kayla G Barnes; Chrispin Chaguza; Isaac T Shawa; Martin M Nyaga; Daniel Hungerford; Umesh D Parashar; Virginia E Pitzer; Arox W Kamng'ona; Miren Iturriza-Gomara; Nigel A Cunliffe; Khuzwayo C Jere Journal: J Infect Dis Date: 2022-06-15 Impact factor: 7.759