Genomic diversity of group A rotavirus strains in patients aged 1–36 months admitted for acute watery diarrhoea in northern India: a hospital-based study

Phase III randomized clinical studies to evaluate the immunogenicity, lot-to-lot consistency, and safety of ROTAVAC® liquid formulations (ROTAVAC 5C & 5D) and non-inferiority comparisons with licensed ROTAVAC® (frozen formulation) in healthy infants

The WHO pre-qualified rotavirus vaccine, ROTAVAC®, is derived naturally from the neonatal 116E rotavirus strain, and stored at -20°C. As refrigerator storage is preferable, immunogenicity and safety of liquid formulations kept at 2-8°C, having excipients to stabilize the rotavirus, with or without buffers, were compared with ROTAVAC® in different clinical studies. Study-1, the pivotal trial for this entire product development work, was a randomized, single-blind trial with two operationally seamless phases: (i) an exploratory phase involving 675 infants in which two formulations, ROTAVAC 5C (LnHRV-1.5 mL and LnHRV-2.0 mL) containing buffer and excipients to stabilize the virus against gastric acidity and temperature, were compared with ROTAVAC®. As the immune response of ROTAVAC 5C (LnHRV-2.0 mL) was non-inferior to ROTAVAC®, it was selected for (ii) confirmatory phase, involving 1,302 infants randomized 1:1:1:1 to receive three lots of LnHRV-2.0 mL, or ROTAVAC®. Primary objectives were the evaluation of non-inferiority and lot-to-lot consistency. The secondary objectives were to assess the safety and interference with the concomitant pentavalent vaccine. As it was separately established that buffers are not required for ROTAVAC®, in Study-2, the safety and immunogenicity of ROTAVAC 5D® (with excipients) were compared with ROTAVAC® and lot-to-lot consistency was assessed in another study. All lots elicited consistent immune responses, did not interfere with UIP vaccines, and had reactogenicity similar to ROTAVAC®. ROTAVAC 5C and ROTAVAC 5D® were immunogenic and well tolerated as ROTAVAC®. ROTAVAC 5D® had comparable immunogenicity and safety profiles with ROTAVAC® and can be stored at 2-8°C, leading to WHO pre-qualification.Clinical Trials Registration: Clinical Trials Registry of India (CTRI): CTRI/2015/02/005577CTRI/2016/11/007481 and CTRI/2019/03/017934.

Whole-genome characterization of common rotavirus strains circulating in Vellore, India from 2002 to 2017: emergence of non-classical genomic constellations

Rotaviruses (RVs) are the most common etiological agent of acute gastroenteritis among young children, even after vaccine introduction in low-income countries. A whole-genome classification representing the 11 RV genes, was introduced for surveillance and characterization of RVs. This study characterized the common circulating strains in Vellore, India from 2002 to 2017 to understand rotavirus strain diversity and evolution using Whole genome sequencing (WGS) carried out on Illumina MiSeq. The 89% (92% of Wa-like, 86% of DS-1-like) of strains had classical constellations, while reassortant constellations were seen in 11% (8% of Wa-like, 14% of DS-1-like) of the strains. The rare E6-NSP4 in combination with DS-1 like G1P[8] and the emergence of the OP-354 subtype of P[8] were identified. Phylogenetics of RV strains revealed multiple subtypes circulating in the past 15 years, with strong evidence of animal to human gene transmission among several strains.

Genotypic characterization of group A rotavirus in children < 5 years of age at tertiary care hospital in North India

PURPOSE

This study was undertaken to find out the positivity of rotavirus associated diarrhoea in children <5 years of age in Meerut district and to determine the genomic diversity of the circulating rotavirus strains in this geographical area.

METHODS

A cross-sectional study was conducted in a tertiary care hospital for a period of one year. A total of 240 stool samples were collected from children suffering from acute diarrhoea and subjected for rotavirus antigen detection by enzyme immunoassay (EIA). The EIA-positive samples were further genotyped to determine the G and P types using semi nested multiplex reverse transcriptase-polymerase chain reaction (RT-PCR). Demographic and clinical parameters were recorded in a pre-designed proforma.

RESULTS

The rotavirus antigen positivity rate was 14.58% in Meerut district. There was male predominance and highest positivity rate was seen in children 13-24 months of age, in winter months and majority of cases belonged to moderate degree of severity. A total of 64% children in the study area were vaccinated and positivity was low in the vaccine group. G9P[4] was the predominant genotype followed by G3P[8]. Uncommon strains G12P[6] and G12P[8] were also reported as circulating genotypes in this study.

CONCLUSIONS

The positivity rate of rotavirus associated diarrhoea has reduced in Meerut district post vaccination. G9P[4] was the most common circulating RV genotype in Meerut. Our study highlights the importance of including the emerging rotavirus strains in future multivalent RV vaccines to make the vaccines regionally more specific.

Demographic Profile and Genotypic Distribution of Rotavirus Gastroenteritis from Rural Haryana, India

OBJECTIVE

To know the prevalence of rotavirus among hospitalized <5 y children, their demographic profile and genotypic distribution of rotavirus strain from tertiary care center of rural Haryana.

METHODS

An observational 3-year study done from June 2016 to June 2019 where children under 5 y of age hospitalized for acute gastroenteritis were enrolled. Various demographic, environmental, and clinical parameters were assessed. Stool samples were collected and sent to CMC, Vellore for rotavirus screening by enzyme immune assay (EIA) and RV-positive samples were genotyped using reverse transcription-polymerase chain reaction (RT-PCR).

RESULTS

Out of 444 stool sample screened, 107 were positive (24.1%) for rotavirus. RV positive cases seen mostly in 6-24 mo age group with moderate to severe dehydration at presentation and peaks in winter months (Dec - Feb). G3P[8] (35.24%) is the most prevalent genotype identified followed by G1P[8] (20.95%), G1P[6] (11.43%), G2P[4] (6.67%) and G12P[8] (2.86%).

CONCLUSION

Continuous surveillance is required to monitor the circulating genotypes in postvaccination phase and assess the effectiveness and impact of the vaccine.

Clinicoepidemiological Profile and Genetic Characterization of Circulating Rotavirus Strain among Children < 5 Years Hospitalized for Acute Gastroenteritis in Western Rajasthan, India

OBJECTIVE

To determine the clinical and epidemiological profile and circulating strains of rotavirus among children less than 5 y of age hospitalized for diarrhea in a tertiary care center of western Rajasthan.

METHOD

Children < 5 y of age admitted for acute gastroenteritis were recruited in this hospital-based surveillance study. Detailed clinical history and sociodemographic information was collected for all enrolled children. Severity of the gastroenteritis was assessed using the 20-point Vesikari Clinical Severity Scoring System. Rotavirus positivity was tested in the stool samples collected from children by commercially available techniques and further molecular characterization done as per defined protocol.

RESULTS

Out of 1055 enrolled children, overall positivity rate of typable rotavirus was 18.95% (169/892). Among children who were less than 24 mo of age, positivity due to rotavirus diarrhea was maximum (24.4%). Distinct seasonality was observed as maximum cases of rotavirus diarrhea were detected in the months of December to February. Commonest G type was G3 (54%) followed by G1 (19%) while predominant P type was P[8] (77%) followed by P[4] (11%). G3P[8] (51.83%) was the commonest genotype observed in the study region.

CONCLUSION

The current study found positivity of rotavirus to be 18.95% among children aged 0-59 mo admitted due to acute gastroenteritis is a tertiary care setting in northern part of India. Emergence of newer predominant strains emphasizes the need of continued surveillance to determine the changing trends.

Acute Gastroenteritis in Children Below 5 Years of Age at Tirupati, Andhra Pradesh, India Post Introduction of Rotavirus Vaccine into National Immunization Programme

OBJECTIVE

To identify the burden of rotavirus acute gastroenteritis (AGE) and the genotypes presenting in the authors' area in the period after introduction of rotavirus vaccine in Universal Immunization Programme (UIP).

METHODS

Children aged less than 5 y and presenting to hospital for the treatment of AGE were enrolled into the study from January 2016 to June 2019. Clinical details including age, gender, extent of illness, number of stools, concomitant vomiting and fever, grade of dehydration, and associated illness were recorded. Stool samples were tested for rotavirus using a commercially available ELISA Kit. Genotyping was performed for the rotavirus antigen-positive samples.

RESULTS

Rotavirus positive AGE was seen in 14.2% of the children. High burden of rotavirus gastroenteritis was seen in the age group of 6-23 mo and more cases were observed from December to February months. In our region the prevalent rotavirus genotypes in positive samples are G3 and G1 in G-typing, P[8] and P[4] in P-typing, respectively. G3P[8] and G1P[8] are the most prevalent genotypes identified in our area with a frequency of 35.1% and 25.9%, respectively. Almost all the cases (97.7%) got discharged and only one patient has died.

CONCLUSION

The findings conclude a declining trend in the rotavirus positive AGE cases in the authors' area after introduction of Rotavac vaccine in the UIP.

Epidemiology of rotavirus diarrhea among children less than 5 years hospitalized with acute gastroenteritis prior to rotavirus vaccine introduction in India

Background

Rotavirus is an important cause of severe diarrhea requiring hospitalization, accounting for approximately 78,000 deaths annually in Indian children below 5 years of age. We present epidemiological data on severe rotavirus disease collected during hospital-based surveillance in India before the introduction of the oral rotavirus vaccine into the national immunization schedule.

Methods

The National Rotavirus Surveillance Network was created involving 28 hospital sites and 11 laboratories across the four geographical regions of India. From September 2012 to August 2016 children less than 5 years of age hospitalized for diarrhea for at least 6 h, were enrolled. After recording clinical details, a stool sample was collected from each enrolled child, which was tested for rotavirus antigen using enzyme immunoassay (EIA). Nearly 2/3rd of EIA positive samples were genotyped using reverse transcription polymerase chain reaction to identify the G and P types.

Results

Of the 21,421 children enrolled during the 4 years surveillance, 36.3% were positive for rotavirus. The eastern region had the highest proportion of rotavirus associated diarrhea (39.8%), while the southern region had the lowest (33.8%). Rotavirus detection rates were the highest in children aged 6–23 months (41.8%), and 24.7% in children aged < 6 months. Although rotavirus associated diarrhea was seen throughout the year, the highest positivity was documented between December and February across all the regions. The most common rotavirus genotype was G1P[8] (52.9%), followed by G9P4 (8.7%) and G2P4 (8.4%).

Conclusions

There is high burden of rotavirus gastroenteritis among Indian children below 5 years of age hospitalized for acute diarrhea thereby highlighting the need for introduction of rotavirus vaccine into the national immunization program and also for monitoring circulating genotypes.

Diversity of rotavirus genotypes circulating in children < 5 years of age hospitalized for acute gastroenteritis in India from 2005 to 2016: analysis of temporal and regional genotype variation

Background

From 2016, the Government of India introduced the oral rotavirus vaccine into the national immunization schedule. Currently, two indigenously developed vaccines (ROTAVAC, Bharat Biotech; ROTASIIL, Serum Institute of India) are included in the Indian immunization program. We report the rotavirus disease burden and the diversity of rotavirus genotypes from 2005 to 2016 in a multi-centric surveillance study before the introduction of vaccines.

Methods

A total of 29,561 stool samples collected from 2005 to 2016 (7 sites during 2005–2009, 3 sites from 2009 to 2012, and 28 sites during 2012–2016) were included in the analysis. Stools were tested for rotavirus antigen using enzyme immunoassay (EIA). Genotyping was performed on 65.8% of the EIA positive samples using reverse transcription- polymerase chain reaction (RT-PCR) to identify the G (VP7) and P (VP4) types. Multinomial logistic regression was used to quantify the odds of detecting genotypes across the surveillance period and in particular age groups.

Results

Of the 29,561 samples tested, 10,959 (37.1%) were positive for rotavirus. There was a peak in rotavirus positivity during December to February across all sites. Of the 7215 genotyped samples, G1P[8] (38.7%) was the most common, followed by G2P[4] (12.3%), G9P[4] (5.8%), G12P[6] (4.2%), G9P[8] (4%), and G12P[8] (2.4%). Globally, G9P[4] and G12P[6] are less common genotypes, although these genotypes have been reported from India and few other countries. There was a variation in the geographic and temporal distribution of genotypes, and the emergence or re-emergence of new genotypes such as G3P[8] was seen. Over the surveillance period, there was a decline in the proportion of G2P[4], and an increase in the proportion of G9P[4]. A higher proportion of mixed and partially typed/untyped samples was also seen more in the age group 0–11 months.

Conclusions

This 11 years surveillance highlights the high burden of severe rotavirus gastroenteritis in Indian children < 5 years of age before inclusion of rotavirus vaccines in the national programme. Regional variations in rotavirus epidemiology were seen, including the emergence of G3P[8] in the latter part of the surveillance. Having pre-introduction data is important to track changing epidemiology of rotaviruses, particularly following vaccine introduction.

Rotavirus gastroenteritis in Indian children < 5 years hospitalized for diarrhoea, 2012 to 2016

Background

In 2016, the Government of India introduced the oral rotavirus vaccine (ROTAVAC, Bharat Biotech, India) in 4 states of India as part of the Universal Immunization Programme, and expanded to 5 more states in 2017. We report four years of data on rotavirus gastroenteritis in hospitalized children < 5 years of age prior to vaccine introduction.

Methods

Children from 7 sites in southern and northern India hospitalized for diarrhoea were recruited between July 2012 and June 2016. Stool samples were screened for rotavirus using enzyme immunoassay (EIA). The EIA positive samples were genotyped by reverse-transcription polymerase chain reaction.

Results

Of the 5834 samples from the 7 sites, 2069 (35.5%) were positive for rotavirus by EIA. Genotyping was performed for 2010 (97.1%) samples. G1P[8](56.3%), G2P[4](9.1%), G9P[4](7.6%), G9P[8](4.2%), and G12P[6](3.7%) were the common genotypes in southern India and G1P[8](36%), G9P[4](11.4%), G2P[4](11.2%), G12P[6](8.4%), and G3P[8](5.9%) in northern India.

Conclusions

The study highlights the high prevalence of rotavirus gastroenteritis in India and the diversity of rotavirus genotypes across different geographical regions. Pre- vaccine surveillance data is necessary to evaluate the potential change in admission rates for gastroenteritis and circulating rotavirus genotypes after vaccine introduction, thus assessing impact.

Electronic supplementary material

The online version of this article (10.1186/s12889-019-6406-0) contains supplementary material, which is available to authorized users.

A Phase 4, multicentre, randomized, single-blind clinical trial to evaluate the immunogenicity of the live, attenuated, oral rotavirus vaccine (116E), ROTAVAC®, administered simultaneously with or without the buffering agent in healthy infants in India

BACKGROUND

The World Health Organization recommends that rotavirus vaccines should be included in all national immunization programs. Some currently licensed oral rotavirus vaccines contain a buffering agent (either as part of a ready-to-use liquid formulation or added during reconstitution) to reduce possible degradation of the vaccine virus in the infant gut, which poses several programmatic challenges (the large dose volume or the reconstitution requirement) during vaccine administration. Because ROTAVAC®, a WHO prequalified vaccine, was derived from the 116E neonatal strain, we evaluated the immunogenicity and safety of ROTAVAC® without buffer and ROTAVAC® with buffer in a phase 4, multicentre, single-blind, randomized clinical trial in healthy infants in India.

METHODS

900 infants, approximately 6, 10 and 14 weeks of age, were assigned to 3 groups to receive ROTAVAC® (0.5 mL dose) orally: (i) 2.5 mL of citrate-bicarbonate buffer 5 minutes prior to administration of ROTAVAC® (Group I), (ii) ROTAVAC®, alone, without any buffer (Group II), or (iii) ROTAVAC®, mixed with buffer immediately before administration (Group III). Non-inferiority was compared among the groups for differences in serological responses (detected by serum anti-rotavirus IgA) and safety.

RESULTS

Geometric mean titers post vaccination at day 84 (28 days after dose 3) were 19.6 (95%CI: 17.0, 22.7), 20.7 (95%CI: 17.9, 24) and 19.2 (95%CI: 16.8, 22.1) for groups I, II and III respectively. Further, seroconversion rates and distribution of adverse events were similar among groups.

CONCLUSIONS

Administration of ROTAVAC® at a 0.5 mL dose volume without buffering agent was shown to be well tolerated and immunogenic. Given the homologous nature of the strain, it is plausible that ROTAVAC® replicates well and confers immunity even without buffer administration.

No direct correlation between rotavirus diarrhea and breast feeding: A meta-analysis

BACKGROUND

Some studies indicated that children with exclusive breast feeding had a reduction in the prevalence of rotavirus diarrhea, while some others held the opposite views. In this study, we aimed to systematically find the associations between rotavirus diarrhea and breast feeding.

METHODS

A literature search up to June 2016 in electronic literature databases, including PubMed and Embase, was performed. The Newcastle-Ottawa Scale was used to conduct the quality assessment of all the selected studies. Statistical analyses were performed using the R package version 3.12 (R Foundation for Statistical Computing, Beijing1, China, meta package), and odds ratio (OR) and 95% confidence interval (CI) were used to assess the strength of the association. The heterogeneity was assessed by Cochran's Q-statistic and I² test, and the sensitivity analysis was performed by trimming one study at a time.

RESULTS

A total of 17 articles, which included 10,841 participants, were investigated in the present meta-analysis. There was no significant difference between the case group and control group (OR, 0.59 95% CI 0.33-1.07) in the meta-analysis of exclusive breast feeding, and no significant difference was found between the case group and the control group (OR, 0.86; 95% CI 0.63-1.16) in the meta-analysis of breast feeding. No significant difference was found between the case group and control group (OR, 0.78 95% CI 0.59-1.04) for all quantitative data.

CONCLUSIONS

There may be no direct correlation between rotavirus diarrhea and breast feeding.

Burden of Rotavirus Diarrhea in Under five Indian Children

NEED AND PURPOSE

Rotavirus is the most common cause of severe diarrhea in infants and young children worldwide. The burden of rotavirus diarrhea in Indian children is not well established. The present study reviewed the epidemiology of rotavirus diarrhea in hospitalized children and in the community, molecular serotyping and under-five mortality caused by rotavirus diarrhea.

METHODS

Publications, reporting rotavirus diarrhea in Indian children, were retrieved through a systematic search of databases including Medline, PubMed, IndMed, websites of WHO, UNICEF, National Family Health Survey, Ministry of Health and Family Welfare, and Government of India. Human studies in English language were included. Age group selected was 0 month to 5 years. No restrictions were applied in terms of study design and time frame.

CONCLUSIONS

Stool sample positivity varied from 4.6% in Kolkata to 89.8% in Manipur, among hospitalized children, and from 4% in Delhi to 33.7% in Manipur in community. Most cases of rotavirus diarrhea in India are caused by G1, G2, and G untypeable strains with distinct regional variations. Rotavirus was identified as an etiological agent in 5.2 to 80.5% cases of nosocomial diarrhea. Data are lacking for rotavirus mortality.

Aetiology of childhood viral gastroenteritis in Lucknow, north India

BACKGROUND & OBJECTIVES

Due to limited availability of data on viral aetiology of acute gastroenteritis in north India, the present study was planned to detect rotavirus, norovirus, sapovirus and astrovirus in stool samples of both in hospitalized and non-hospitalized children less than five years of age presenting with acute gastroenteritis.

METHODS

A total of 278 stool samples from equal number of children were tested for rotavirus antigen using ELISA and for norovirus, sapovirus and astroviruses by reverse transcription (RT)-PCR.

RESULTS

Of the 169 samples from hospitalized patients, rotavirus, norovirus, sapovirus and astrovirus were detected in 19.5, 2.3, 3.5 and 2.9 per cent samples, respectively. Of the 109 samples collected from the non-hospitalized patients, frequency of rotavirus and sapovirus detection was 9.1 and 1.8 per cent, respectively while norovirus and astrovirus were not detected.

INTERPRETATION & CONCLUSIONS

Rotavirus was the most frequent cause of viral gastroenteritis in both hospitalized and non-hospitalized children. Maximum positivity of the viruses was seen in children less than two years of age.

Global occurrence and emission of rotaviruses to surface waters

Group A rotaviruses (RV) are the major cause of acute gastroenteritis in infants and young children globally. Waterborne transmission of RV and the presence of RV in water sources are of major public health importance. In this paper, we present the Global Waterborne Pathogen model for RV (GloWPa-Rota model) to estimate the global distribution of RV emissions to surface water. To our knowledge, this is the first model to do so. We review the literature to estimate three RV specific variables for the model: incidence, excretion rate and removal during wastewater treatment. We estimate total global RV emissions to be 2 × 1018 viral particles/grid/year, of which 87% is produced by the urban population. Hotspot regions with high RV emissions are urban areas in densely populated parts of the world, such as Bangladesh and Nigeria, while low emissions are found in rural areas in North Russia and the Australian desert. Even for industrialized regions with high population density and without tertiary treatment, such as the UK, substantial emissions are estimated. Modeling exercises like the one presented in this paper provide unique opportunities to further study these emissions to surface water, their sources and scenarios for improved management.

Prevalence of rotavirus diarrhea among hospitalized under-five children

OBJECTIVE

To estimate the prevalence of rotavirus diarrhea among hospitalized children less than 5 years of age in Kerala State and to determine the circulating strains of rotavirus in Kerala.

DESIGN

Multicenter, cross-sectional study.

SETTING

Eight representative hospitals in Kunnathunadu Thaluk, Ernakulam district, Kerala.

PARTICIPANTS

Children in the age group under 5 years.

METHODS

Hospitalized children admitted with acute diarrhea were examined and standardized case report form was used to collect demographic, clinical and health outcome. Stool specimens were collected and ELISA testing was done. ELISA rotavirus positive samples were tested by reverse transcription PCR for G and P typing (CMC Vellore).

RESULTS

Among the 1827 children, 648 (35.9%) were positive for rotavirus by the Rotaclone ELISA test. The prevalence of rotavirus diarrhea in infants less than 6 months of age was 24.7%; 6- 11 months 31.9%; 12- 23 months 41.9%; 24- 35 months 46.9%; and 33.3% in 36- 59 months. Rotavirus infections were most common during the dry months from January through May. G1P[8] (49.7%) was the most common strain identified followed by G9P[8] (26.4%), G2P[4] (5.5%), G9P[4] (2.6%) and G12P[6] (1.3%).

CONCLUSIONS

The prevalence of rotavirus diarrhea among hospitalized children less than 5 years is high in Ernakulam district, Kerala State.

Global seasonality of rotavirus disease

BACKGROUND

A substantial number of surveillance studies have documented rotavirus prevalence among children admitted for dehydrating diarrhea. We sought to establish global seasonal patterns of rotavirus disease before the introduction of widespread vaccination.

METHODS

We reviewed studies of rotavirus detection in children with diarrhea published since 1995. We assessed potential relationships between seasonal prevalence and locality by plotting the average monthly proportion of diarrhea cases positive for rotavirus according to geography, country development and latitude. We used linear regression to identify variables that were potentially associated with the seasonal intensity of rotavirus.

RESULTS

Among a total of 99 studies representing all 6 geographic regions of the world, patterns of year-round disease were more evident in low- and low-middle income countries compared with upper-middle and high-income countries where disease was more likely to be seasonal. The level of country development was a stronger predictor of strength of seasonality (P = 0.001) than geographic location or climate. However, the observation of distinctly different seasonal patterns of rotavirus disease in some countries with similar geographic location, climate and level of development indicate that a single unifying explanation for variation in seasonality of rotavirus disease is unlikely.

CONCLUSION

While no unifying explanation emerged for varying rotavirus seasonality globally, the country income level was somewhat more predictive of the likelihood of having seasonal disease than other factors. Future evaluation of the effect of rotavirus vaccination on seasonal patterns of disease in different settings may help understand factors that drive the global seasonality of rotavirus disease.

A systematic review of rotavirus strain diversity in India, Bangladesh, and Pakistan

Of the estimated half-million deaths from rotavirus globally each year, approximately one-third (N = 160,000 deaths) occur in the Indian subcontinent (defined as India, Bangladesh, and Pakistan). Two commercial vaccines are available for use and recommended by WHO, although the prohibitive vaccine price has limited their introduction into routine childhood immunization programs. New rotavirus vaccines are in late clinical development, including two advanced candidates in India. As significant shifts in rotavirus strain diversity have occurred in the past three decades and questions remain regarding whether strain replacement may occur following introduction of rotavirus vaccines, it is important to understand the temporal and regional strain diversity profile before vaccine introduction. We reviewed 33 peer-reviewed manuscripts from the Indian subcontinent and found that the most common G-types (G1-4) and P-types (P[4] and P[8]) globally accounted for three-fourths of all strains in the subcontinent. However, strains varied by region, and temporal analysis showed the decline of G3 and G4 in recent years and the emergence of G9 and G12. Our findings underscore the large diversity of rotavirus strains in the Indian subcontinent and highlight the need to conduct surveillance on a regional scale to better understand strain diversity before and after rotavirus vaccine introduction.

Seasonality of rotavirus in South Asia: a meta-analysis approach assessing associations with temperature, precipitation, and vegetation index

BACKGROUND

Rotavirus infection causes a significant proportion of diarrhea in infants and young children worldwide leading to dehydration, hospitalization, and in some cases death. Rotavirus infection represents a significant burden of disease in developing countries, such as those in South Asia.

METHODS

We conducted a meta-analysis to examine how patterns of rotavirus infection relate to temperature and precipitation in South Asia. Monthly rotavirus data were abstracted from 39 published epidemiological studies and related to monthly aggregated ambient temperature and cumulative precipitation for each study location using linear mixed-effects models. We also considered associations with vegetation index, gathered from remote sensing data. Finally, we assessed whether the relationship varied in tropical climates and humid mid-latitude climates.

RESULTS

Overall, as well as in tropical and humid mid-latitude climates, low temperature and precipitation levels are significant predictors of an increased rate of rotaviral diarrhea. A 1°C decrease in monthly ambient temperature and a decrease of 10 mm in precipitation are associated with 1.3% and 0.3% increase above the annual level in rotavirus infections, respectively. When assessing lagged relationships, temperature and precipitation in the previous month remained significant predictors and the association with temperature was stronger in the tropical climate. The same association was seen for vegetation index; a seasonal decline of 0.1 units results in a 3.8% increase in rate of rotavirus.

CONCLUSIONS

In South Asia the highest rate of rotavirus was seen in the colder, drier months. Meteorological characteristics can be used to better focus and target public health prevention programs.

Burden of rotavirus gastroenteritis and distribution of rotavirus strains in Asia: a systematic review

BACKGROUND

Rotavirus is the leading cause of severe diarrhea in children worldwide. We systematically reviewed the burden of rotavirus gastroenteritis (RVGE) and distribution of rotavirus strains in Asia.

METHODS

We searched MEDLINE, EMBASE and the World Health Organization (WHO) website for the term "rotavirus" and the name of each country. We included studies that were conducted in children between 2000 and 2011 and that examined the epidemiology, health and/or economic burden of RVGE, and G and P-type distribution in Eastern, South East, Southern and Central Asia. Random effects models were used to pool the proportions of RVGE. We also estimated child mortality due to RVGE using the updated WHO and United Nations Children's Fund's mortality estimates in 2008.

RESULTS

The search identified 113 eligible articles. The incidence rates of rotavirus-related hospitalizations in children under 5 years of age ranged from 2.1 to 20.0 cases per 1000 children per year with the highest rates reported in Bangladesh, South Korea, Taiwan, Thailand, and Vietnam. Rotavirus accounted for 37.5% of year-round hospitalized gastroenteritis cases, with higher proportions reported in South East Asia. Rotavirus was associated with approximately 145,000 deaths every year in Asia, with the greatest numbers occurring in India, Pakistan, and Indonesia. The highest annual societal costs of treating RVGE were reported in China (US$365 million), followed by Japan (US$254 million) and India (US$41-72 million). A diversity of rotavirus G and P-types was observed across Asia and the distribution of strains differed by country and year. The most common strains were G1P[8] (23.6%), G2P[4] (11.8%), G3P[8] (18.9%), and G9P[8] (7.4%).

CONCLUSIONS

Rotavirus is associated with substantial hospitalizations and deaths among children and causes large healthcare expenditures throughout Asia. Safe and effective rotavirus vaccines could substantially reduce the burden of disease.