New insights into rotavirus vaccines

Epidemiological, molecular, and clinical features of rotavirus infections among pediatrics in Qatar

Acute gastroenteritis (AGE) remains a major cause of diarrhea in developing and developed countries. Rotavirus (RV) is a leading cause of severe pediatric diarrhea worldwide. Here we report on the prevalence of circulating genotypes in association with demographics and clinical manifestations outcomes in Qatar. A total of 231 RV-positive fecal samples were collected from children suffering from AGE during 3 years study period between June 2016 and June 2019. The age of the subjects ranged between 2 months and 14 years (median of 16 months). The VP4 and VP7 were amplified and sequenced. Phylogenetic analyses were performed using MEGA7.0. Pearson's chi-squared test was used to determine significant differences for comparisons of general categorical variables. RV infections were most common in children between 1 and 3 years of age (49%), followed by those < 1 year and > 3 years of age (33% and 28%, respectively). RV infections were more frequent in males than females, with a ratio of 1.4:1. RV infections occurred throughout the year, with a noticeable increase in summer (42.8%) and a drop in winter (20.1%). RV genotypes G3P[8] (30.8%), G2P[8] (12.3%), G4P[8] (11.7%), and G1P[8] (10.4%) were the common genotypes during the study period. The G3P[8] strain detected in our study revealed similarities to the equine-like G3P[8] (10.3%; 24/231) (KT988229.1), Wa-like genomic constellation (9%; 21/231) (MF563894.1), and DS-1-like strains (6.4%; 15/231) (LC386081.1). Based on the Vesikari score system, severe clinical illness including diarrhea and vomiting (average frequency: 4 to 5 times/day) was recorded for G3P[8] group, followed by G9P[8], G4P[8], and G1P[8]. Higher incidence for G3P[8], G2P[8], G4P[8], and G1P[8] were reported in Qatari subjects compared to other nationalities. The multinational status of a small country explains the wide diversity of circulating RV genotypes in Qatar. The highest prevalence and severe illnesses were recorded to G3P[8], which is different from other surrounding countries/global levels.

G2P[4] rotavirus outbreak in Belu, East Nusa Tenggara Province, Indonesia, 2018

Rotavirus is a major cause of acute gastroenteritis (AGE) in children worldwide. However, rotavirus outbreak has rarely been reported in Indonesia. This study aims to identify the causative agent for AGE outbreak among children in Belu, East Nusa Tenggara, Indonesia in 2018. All the samples were negative for bacteria (Salmonella, V. cholera) and Norovirus. Ten out of 11 stool samples were rotavirus-positive by immunochromatography testing. Reverse-transcription polymerase chain reaction (RT-PCR) and phylogenetic analyses revealed that rotavirus G2P[4] was the possible causative agent for the AGE outbreak, although sample size was limited. These findings suggest that the AGE outbreak was caused by rotavirus G2P[4], highlighting the importance of rotavirus surveillance.

Prevalence and molecular typing of rotavirus in children with acute diarrhoea in Northeastern Colombia

After the introduction of the rotavirus vaccine, the number of rotavirus-associated deaths and the predicted annual rotavirus detection rate had slightly declined worldwide. Taking in account that in Colombia, Rotarix vaccine was introduced in 2009, the purpose of this study was to evaluate the presence of rotavirus A in children under five years who were treated for acute diarrhoea in Bucaramanga, Colombia and, moreover, to determine the genotypes of rotavirus present in those children. We performed an analytical cross-sectional study of rotavirus A in faecal samples from children up to five years of age. Stool samples were screened for rotavirus A using a lateral-flow immunochromatographic assay and confirmed using a VP6 sandwich ELISA. Genotyping of rotavirus A-positive samples was performed by PCR and sequencing of VP7 and VP4 genes. The overall prevalence of rotavirus was 30.53% (95% confidence interval [CI] 21.2 - 39.7). Most of the children with rotavirus (86.2%) had received two doses of the rotavirus vaccine. G3 strains accounted for the vast majority of cases (82.8%), followed by G12 strains (13.8%) and G3/G9 coinfections (3.4%). Among the P genotypes, P[8] was the most prevalent (69%), followed by P[9] (31%). The most common G[P] genotype combination was G3P[8], followed by G3P[9]. The main finding in this study was that rotavirus, in a Colombian region, is still an important pathogen in children under five years old, previously vaccinated. The results showed that different factors, such as kindergarten attendance, could explain the epidemiology and transmission of rotavirus in Bucaramanga.

Changes in Rotavirus Genotypes before and after Vaccine Introduction: a Multicenter, Prospective Observational Study in Three Areas of Japan

In Japan, monovalent and pentavalent rotavirus (RV) vaccines were approved in 2011 and 2012, respectively. To monitor changes in the RV genotypes before and after vaccine introduction, we performed a prospective observational study among children (＜ 5 years) with gastroenteritis who tested RV-positive on antigen rapid tests. Stool samples were collected from 3 different sites in Japan: Tsu City, Mie Prefecture; Kurashiki City, Okayama Prefecture; and Isumi City, Chiba Prefecture. RV genotypes were determined using reverse transcription-polymerase chain reaction. In Tsu City, G3P[8] was dominant (61.0-77.1%) before vaccine introduction, but decreased after introduction. Meanwhile, in an inverse proportion to the decrease in G3P[8], G1P[8] increased until the 2013/14 season, when a sudden predominance of G2P[4] (100%) occurred. A similar trend was observed in Kurashiki City in terms of the extent of reduction in G3P[8] and the emergence of G2P[4]. In Isumi City, G1P[8] was dominant (70.3%) before vaccine introduction, and G9P[8] became predominant (83.3%) in the 2013/14 season. To determine whether the genotype changes are attributable to vaccines or natural epidemiological changes, ongoing continuous monitoring of the RV genotypes is required.

Comparative analysis of the immunogenicity of monovalent and multivalent rotavirus immunogens

The strategies for developing rotavirus (RV) vaccines have always been controversial. At present, both the monovalent RV vaccine and the multivalent RV vaccine have displayed excellent safety and efficacy against RV infection and shown cross-reactive immunity, which laid the question whether the multivalent RV vaccine could be replaced by the monovalent RV vaccine. In this study, we focused on comparing the immunogenicity (serum neutralization activity and protection against homotypic and heterotypic RVs’ challenge) of individual standard RV strains (monovalent RV immunogens) and different combinations of them (multivalent RV immunogens). In result, RV immunogens showed general immunogenicity and heterotypic reaction but the multivalent RV immunogens exhibited greater serum neutralization activity and stronger heterotypic reaction than the monovalent RV immunogens (P<0.05). As to the protection, the multivalent RV immunogens also revealed more rapid and stronger protection against homotypic and heterotypic RVs’ challenge than the monovalent RV immunogens. The results demonstrated that both the monovalent and multivalent RV immunogens exhibited high immunogenicity, but the monovalent RV immunogens could not provide enough neutralization antibodies to protect MA104 cells against the infection with heterotypic RV strains and timely protection against homotypic and heterotypic RVs, so the multivalent RV vaccine could not be replaced by the monovalent RV vaccine.

In vitro Antiviral Activity of Rubia cordifolia Aerial Part Extract against Rotavirus

The root of Rubia cordifolia has been used traditionally as a hemostatic agent, while the aerial part of the plant consisting of leaf and stem is known to exhibit anti-diarrheal properties and has been widely used as a remedy in many parts of China. As rotavirus is one of the most commonly associated diarrhea-causing pathogen, this study aims to investigate the anti-rotaviral effect of R. cordifolia aerial part (RCAP). The cytotoxicity of RCAP toward MA-104 cells was evaluated using the WST-8 assay. Colloidal gold method and real time polymerase chain reaction (qPCR) assay were used to confirm the findings of the antiviral assay. Then, 4',6-diamidino-2-phenylindole (DAPI) staining method was subsequently used to investigate the mode of death among the cells. And the representative components of aqueous extract were isolated and identified. It was shown that both the viability of MA-104 cells and the viral load were reduced with increasing concentration of the extract. DAPI staining showed that virus-induced apoptosis was the cause of the low cell viability and viral load, an effect which was accelerated with incubation in the aqueous herbal extract. The major compounds postulated to exhibit this activity were isolated from the aqueous herbal extract and identified to be compounds Xanthopurpurin and Vanillic Acid. This study showed that RCAP extract effectively inhibited rotavirus multiplication by promoting virus-induced apoptosis in MA-104 cells.

Impact of vaccination uptake on hospitalizations due to rotavirus acute gastroenteritis in 2 different socioeconomic areas of Spain

Rotavirus is the leading cause of hospitalization due to acute gastroenteritis (AGE) in infants and toddlers. However, rotavirus vaccination has been associated with a decline in hospitalization rates due to rotavirus AGE. A descriptive retrospective study was conducted to analyze the impact of rotavirus vaccination on the rate of hospitalizations due to AGE among children ≤2 years old in 2 areas of the province of Almería, Spain. After eight years of rotavirus vaccination, rates of hospitalizations due to rotavirus AGE are diminished. This decline is closely related to vaccine coverage in the studied areas.

High-Pressure Inactivation of Rotaviruses: Role of Treatment Temperature and Strain Diversity in Virus Inactivation

Rotavirus (RV) is the major etiological agent of acute gastroenteritis in infants worldwide. Although high-pressure processing (HPP) is a popular method to inactivate enteric pathogens in food, the sensitivity of different virus strains within same species and serotype to HPP is variable. This study aimed to compare the barosensitivities of seven RV strains derived from four serotypes (serotype G1, strains Wa, Ku, and K8; serotype G2, strain S2; serotype G3, strains SA-11 and YO; and serotype G4, strain ST3) following high-pressure treatment. RV strains showed various responses to HPP based on the initial temperature and had different inactivation profiles. Ku, K8, S2, SA-11, YO, and ST3 showed enhanced inactivation at 4°C compared to 20°C. In contrast, strain Wa was not significantly impacted by the initial treatment temperature. Within serotype G1, strain Wa was significantly (P < 0.05) more resistant to HPP than strains Ku and K8. Overall, the resistance of the human RV strains to HPP at 4°C can be ranked as Wa > Ku = K8 > S2 > YO > ST3, and in terms of serotype the ranking is G1 > G2 > G3 > G4. In addition, pressure treatment of 400 MPa for 2 min was sufficient to eliminate the Wa strain, the most pressure-resistant RV, from oyster tissues. HPP disrupted virion structure but did not degrade viral protein or RNA, providing insight into the mechanism of viral inactivation by HPP. In conclusion, HPP is capable of inactivating RV at commercially acceptable pressures, and the efficacy of inactivation is strain dependent.