Rotavirus Infection in the Auckland Region After the Implementation of Universal Infant Rotavirus Vaccination: Impact on Hospitalizations and Laboratory Implications

Global Estimates of Rotavirus Hospitalizations Among Children Below 5 Years in 2019 and Current and Projected Impacts of Rotavirus Vaccination

BACKGROUND

Rotavirus vaccine impact on rotavirus hospitalizations is not well documented globally. We performed a systematic review to estimate the number of rotavirus hospitalizations that (1) occur annually, (2) are currently prevented by rotavirus vaccines, and (3) could be prevented with improved vaccine coverage and universal vaccine introduction.

METHODS

We systematically reviewed articles indexed in the PubMed database published from January 1, 2000, to December 31, 2019. We included all primary peer-reviewed studies with rotavirus hospitalization rates for children below 5 years that reported data prior to vaccine introduction, utilized at least one continuous year of data collection, and collected hospitalization data after 2000 using active surveillance. We grouped pre-vaccine country estimates by childhood mortality strata and calculated the median rate among each group. We then assigned the mortality stratum-specific hospitalization rates to each country and calculated the number of rotavirus hospitalizations by country, mortality strata, and World Health Organization region.

RESULTS

Our search strategy identified 4590 manuscripts, of which 32 were included in the final dataset. In 2019, an estimated 1 760 113 (interquartile range [IQR]: 1 422 645-2 925 372) rotavirus hospitalizations occurred globally, with 524 871 (IQR: 415 987-814 835) prevented by rotavirus vaccination. With universal introduction of rotavirus vaccines and increased vaccine coverage, we estimate that an additional 751 609 (IQR: 607 671-1 318 807) rotavirus hospitalizations can be prevented annually.

CONCLUSIONS

This analysis highlights the continued burden of rotavirus hospitalizations among children below 5 years. A large, preventable proportion of this burden could be eliminated by expanding introductions to new countries and increasing rotavirus vaccine coverage to levels seen with other childhood vaccinations.

Detection of diarrhoea associated rotavirus and co-infection with diarrhoeagenic pathogens in the Littoral region of Cameroon using ELISA, RT-PCR and Luminex xTAG GPP assays

Background

Despite the global roll-out of rotavirus vaccines (RotaTeq/Rotarix / ROTAVAC/Rotasiil), mortality and morbidity due to group A rotavirus (RVA) remains high in sub-Saharan Africa, causing 104,000 deaths and 600,000 hospitalizations yearly. In Cameroon, Rotarix™ was introduced in March 2014, but, routine laboratory diagnosis of rotavirus infection is not yet a common practice, and vaccine effectiveness studies to determine the impact of vaccine introduction have not been done. Thus, studies examining RVA prevalence post vaccine introduction are needed. The study aim was to determine RVA prevalence in severe diarrhoea cases in Littoral region, Cameroon and investigate the role of other diarrheagenic pathogens in RVA-positive cases.

Methods

We carried out a study among hospitalized children < 5 years of age, presenting with acute gastroenteritis in selected hospitals of the Littoral region of Cameroon, from May 2015 to April 2016. Diarrheic stool samples and socio-demographic data including immunization and breastfeeding status were collected from these participating children. Samples were screened by ELISA (ProSpecT™ Rotavirus) for detection of RVA antigen and by gel-based RT-PCR for detection of the VP6 gene. Co-infection was assessed by multiplexed molecular detection of diarrheal pathogens using the Luminex xTAG GPP assay.

Results

The ELISA assay detected RVA antigen in 54.6% (71/130) of specimens, with 45, positive by VP6 RT-PCR and 54, positive using Luminex xTAG GPP. Luminex GPP was able to detect all 45 VP6 RT-PCR positive samples. Co-infections were found in 63.0% (34/54) of Luminex positive RVA infections, with Shigella (35.3%; 12/34) and ETEC (29.4%; 10/34) detected frequently. Of the 71 ELISA positive RVA cases, 57.8% (41/71) were fully vaccinated, receiving two doses of Rotarix.

Conclusion

This study provides insight on RVA prevalence in Cameroon, which could be useful for post-vaccine epidemiological studies, highlights higher than expected RVA prevalence in vaccinated children hospitalized for diarrhoea and provides the trend of RVA co-infection with other enteric pathogens. RVA genotyping is needed to determine circulating rotavirus genotypes in Cameroon, including those causing disease in vaccinated children.

A review of rotavirus vaccine use in Asia and the Pacific regions: challenges and future prospects

Introduction: Rotavirus infection causes a significant proportion of diarrhea disease burden in children <5 years of age in Asia and the Pacific regions. The World Health Organization recommends that rotavirus vaccination should be included in national immunization programs to prevent rotavirus gastroenteritis (RVGE).Areas covered: A literature review was performed to identify and summarize published evidence on RVGE epidemiology and status of rotavirus vaccine use, including the impact and cost-effectiveness of rotavirus vaccination programs in Asia and the Pacific regions (49 countries) during the period 2000-2018.Expert opinion: Rotavirus vaccination programs have successfully reduced the burden of RVGE in many countries. However, such programs still do not exist in most Asia-Pacific countries, and therefore the burden of RVGE remains high in children <5 years of age. Challenges to vaccine implementation include a lack of surveillance data; safety concerns around intussusception; a general lack of awareness about RVGE disease epidemiology and vaccines among physicians, policy-makers, and parents; insufficient cost-effectiveness analyses; and potential issues with vaccine affordability including vaccination costs and lack of political will. Recommendations to overcome these challenges include developing cost-effectiveness analyses for more diverse national and regional settings, providing non-governmental support for low-income countries, and improving advocacy efforts.Plain language summaryWhat is the context?• Rotavirus (RV) infection causes acute gastroenteritis (GE) in children under 5 years of age.• Rotavirus vaccination (RVV) implementation has been slow in Asia and the Pacific (AP) regions, which could be responsible for the region falling behind in their fight against RVGE.What is new?• RVV via national immunization programs (NIPs) is available in 8/49 countries and through the private market or non-governmental support in other countries. Coverage rates vary between countries, possibly driven by the mechanism through which RVV is available.• A substantial positive impact of RVV on RVGE disease burden with a very low risk of intestinal intussusception for up to 7 days after RVV has been documented in the AP regions.• Economic evaluation studies, mainly cost-effectiveness analyses, predict a significant reduction in treatment costs related to RVGE and its complications showing that RVV is good value for money.What is the impact?• The prospect of continued safe and effective use of RVV in the AP regions is promising.• Challenges to RVV implementation include establishing evidence of burden of disease, poor awareness of rotavirus vaccines, limited evidence from cost-effectiveness analyses from several countries, issues of affordability of the vaccine and a lack of political will.• Recommendations for RVV implementation into the NIPs include conducting clinical and cost-effectiveness studies in countries where these are not available, establishing reliable surveillance mechanisms, providing non-governmental support for low-income countries and improving advocacy efforts.• Maintenance of high vaccination coverage is needed in countries that have implemented national RVV programs.Graphical abstract[Formula: see text].

Rotavirus Genotype Trends and Gastrointestinal Pathogen Detection in the United States, 2014-16: Results from the New Vaccine Surveillance Network

BACKGROUND

Following the implementation of rotavirus vaccination in 2006, severe acute gastroenteritis (AGE) due to group A rotavirus (RVA) has substantially declined in USA (US) children. We report the RVA genotype prevalence as well as co-infection data from seven US New Vaccine Surveillance Network (NVSN) sites during three consecutive RVA seasons, 2014-2016.

METHODS

A total of 1041 stool samples that tested positive for RVA by Rotaclone enzyme immunoassay (EIA) were submitted to the Centers for Disease Control and Prevention (CDC) for RVA genotyping and multipathogen testing.

RESULTS

A total of 795 (76%) contained detectable RVA at CDC. Rotavirus disease was highest in children < 3 years of age. Four G types (G1, G2, G9, and G12) accounted for 94.6% of strains while two P types (P[4] and P[8]) accounted 94.7% of the strains. Overall, G12P[8] was the most common genotype detected in all three seasons. Stepwise conditional logistic analysis found year and study site were significant predictors of genotype. Twenty four percent (24%) of RVA-positive specimens contained other AGE pathogens.

CONCLUSIONS

G12P[8] predominated over three seasons, but strain predominance varied by year and study site. Ongoing surveillance provides continuous tracking and monitoring of US genotypes during the post vaccine era.

Introduction of rotavirus vaccination in a Swedish region: assessing parental decision-making, obtained vaccination coverage and resulting hospital admissions

AIM

This study evaluated the introduction of rotavirus vaccination in Jönköping County, Sweden, starting in 2014. This project explored the parental factors that influenced the decision to vaccinate and studied the obtained vaccination coverage and its potential influence on hospital admissions due to acute gastroenteritis.

METHODS

This was a descriptive, cross-sectional study based on a study-specific questionnaire (n = 356) and regional statistical data on vaccination coverage and hospital admissions in Jönköping County, Sweden.

RESULTS

Central aspects when deciding on vaccination were vaccine efficacy and safety, that the vaccine was offered to all children, and recommended by healthcare professionals. One in five parents expressed uncertainty about whether they had sufficient information to make a decision. However, the rotavirus vaccination coverage was elevated from 76.1% to 81.0% and the hospital admissions due to acute gastroenteritis decreased by approximately 60%.

CONCLUSION

The results highlight the necessity for Child Health Services to have solid knowledge regarding vaccinations, to understand individual parental issues and to support uncertain parents. The high vaccination coverage achieved is an indication of the trust in healthcare professionals and is considered to be a major contributing factor to the substantial reduction of hospital admissions due to acute gastroenteritis.

Diagnosis of rotavirus infection in a vaccinated population: Is a less sensitive immunochromatographic method more suitable for detecting wild-type rotavirus than real-time RT-PCR?

BACKGROUND

Diagnosis of wild-type rotavirus disease may be complicated by the detection of vaccine-derived virus which can be detected in stool samples following immunisation. We evaluate an immunochromatographic assay and real-time RT-PCR to determine which is more suitable for the detection of wild-type rotavirus.

OBJECTIVES

To compare the Ct values of wild-type rotavirus and Rotarix determined by real-time RT-PCR. To establish the Ct value corresponding to the limit of detection of the immunochromatographic Combi-Strip method (Coris, BioConcept).

STUDY DESIGN

Retrospective review of real-time RT-PCR Ct values was performed on 100 samples tested by a pan-rotavirus assay (n = 50 wild-type, n = 50 Rotarix). Secondly the limit of detection of the Combi-Strip assay was determined by testing; wild-type rotavirus (n = 33, Ct range 6.85-34.26) samples, Rotarix (n = 9, Ct range 20.86-34.26) samples and rotavirus negative (n = 21) samples.

RESULTS

The median Ct of 50 wild-type rotavirus was Ct 12.43; range 6.11-32.66 compared with the median of 50 Rotarix, Ct 29.09; range 18.91-35.28, p=<0.0001. The limit of detection of the Combi-Strip method was approximately Ct 18. The 21 rotavirus negative samples were negative by real-time RT-PCR and Combi-Strip.

CONCLUSIONS

We found the Ct value was significantly lower, and therefore the viral load higher, for wild-type rotavirus compared to detectable Rotarix. The Combi-Strip assay detects most wild-type infections; however, it lacks sensitivity to detect low-level wild-type rotavirus and, beneficially, is unlikely to detect Rotarix. It is not a more suitable method than real-time RT-PCR when a definitive rotavirus result is required.

Suboptimal performance of rotavirus testing in a vaccinated community population should prompt laboratories to review their rotavirus testing algorithms in response to changes in disease prevalence

Rotavirus vaccine has reduced disease prevalence in many countries. Consequently, we aimed to assess the reliability of a rotavirus immunoassay in the community population of Auckland and Northland, New Zealand. Between 22 October 2015 and 31 December 2016, 2873 fecal samples were tested by enzyme immunoassay (EIA, Rotascreen II, Microgen, UK) from 2748 patients (median age 8 years, range 0-101 years). Eighty-nine (3.1%) samples were reactive; 86 samples were tested by a second method. Rotavirus was confirmed in 49/86 (57%). Positive rotavirus EIAs were more likely to be confirmed in samples from cases ≥1 year of age (positive predictive value [PPV] 61%, 95% confidence interval [CI] 50-72%, P = 0.049) and in spring/summer (PPV 67%, 95% CI 55-78%, P = 0.003). Reactive rotavirus tests required confirmatory testing regardless of demographic, vaccine, or seasonal factors; a review of rotavirus testing algorithms may be necessary in other vaccinated community populations.