Virus Genotype Distribution and Virus Burden in Children and Adults Hospitalized for Norovirus Gastroenteritis, 2012–2014, Hong Kong

Abstract

We conducted a 2-year hospital-based study on norovirus gastroenteritis among children and adults between August 2012 and September 2014. A total of 1,146 norovirus cases were identified. Young children (aged ≤ 5 years) accounted for a majority (53.3%) of cases. Hospitalization incidence exhibited a U-shaped pattern with the highest rate in young children (1,475 per 100,000 person-years), followed by the elderly aged > 84 years (581 per 100,000 person-years). A subset (n = 395, 34.5%) of cases were selected for norovirus genotyping and noroviral load measurement. Non-GII.4 infections were more commonly observed in young children than in older adults (aged > 65 years) (20.5% versus 9.2%; p < 0.05). In young children, the median noroviral load of GII.4 and non-GII.4 cases was indistinguishably high (cycle threshold value, median [interquartile range]: 16.6 [15.2–19.3] versus 16.6 [14.9–21.6]; p = 0.45). Two age-specific non-GII.4 genotypes (GII.3 and GII.6) were identified among young children. These findings may have implications in norovirus vaccination strategy.

Norovirus genotype distribution in outbreaks of acute gastroenteritis among children and older people: an 8-year study

“…Additionally, a sharp increase in outbreaks was observed in K/Ns compared with the other two facilities. In general, the norovirus load decreases with increasing age, especially in young children aged <5 years, although the median norovirus load of any genotype is high [33]. A higher norovirus load or the environment in K/Ns might affect the rapid spread of the infection.…”

Increased Detection of Emergent Recombinant Norovirus GII.P16-GII.2 Strains in Young Adults, Hong Kong, China, 2016–2017

“…Since August 2012, we have conducted an ongoing molecular surveillance of norovirus genotype distribution in all hospitalized gastroenteritis patients in our teaching hospital in Hong Kong ( 6 ). We admitted patients on the basis of clinical severity at presentation and routinely tested for norovirus on the basis of clinical suspicion of viral gastroenteritis.…”

“…We admitted patients on the basis of clinical severity at presentation and routinely tested for norovirus on the basis of clinical suspicion of viral gastroenteritis. We collected stool samples and tested them for norovirus by using a 1-step quantitative reverse transcription PCR assay ( 6 ). We then subjected norovirus RNA–positive samples to genotyping that targeted the 5′ end (region C) of the viral protein 1 (VP1) gene as previously described ( 6 ).…”

“…We collected stool samples and tested them for norovirus by using a 1-step quantitative reverse transcription PCR assay ( 6 ). We then subjected norovirus RNA–positive samples to genotyping that targeted the 5′ end (region C) of the viral protein 1 (VP1) gene as previously described ( 6 ). After 
Sanger-sequencing amplicons, we assigned norovirus genotypes by using the RIVM online norovirus genotyping tool (http://www.rivm.nl/mpf/norovirus/typingtool).…”

Complete Genome Sequence of an Emergent Recombinant GII.P16-GII.2 Norovirus Strain Associated with an Epidemic Spread in the Winter of 2016-2017 in Hong Kong, China

“…Preliminary virus capsid genotyping was performed as previously described (6). The complete genome of the virus was determined using a metagenomic next-generation sequencing approach.…”