Rotavirus and severe childhood diarrhea Parashar, Umesh D; Gibson, Christopher J; Bresee, Joseph S ...
Emerging infectious diseases,
02/2006, Letnik:
12, Številka:
2
Journal Article
Recenzirano
Odprti dostop
Studies published between 1986 and 1999 indicated that rotavirus causes approximately 22% (range 17%-28%) of childhood diarrhea hospitalizations. From 2000 to 2004, this proportion increased to 39% ...(range 29%-45%). Application of this proportion to the recent World Health Organization estimates of diarrhea-related childhood deaths gave an estimated 611,000 (range 454,000-705,000) rotavirus-related deaths.
The development of rotavirus vaccines that are based on heterotypic or serotype-specific immunity has prompted many countries to establish programs to assess the disease burden associated with ...rotavirus infection and the distribution of rotavirus strains. Strain surveillance helps to determine whether the most prevalent local strains are likely to be covered by the serotype antigens found in current vaccines. After introduction of a vaccine, this surveillance could detect which strains might not be covered by the vaccine. Almost 2 decades ago, studies demonstrated that 4 globally common rotavirus serotypes (G1–G4) represent >90% of the rotavirus strains in circulation. Subsequently, these 4 serotypes were used in the development of reassortant vaccines predicated on serotype-specific immunity. More recently, the application of reverse-transcription polymerase chain reaction genotyping, nucleotide sequencing, and antigenic characterization methods has confirmed the importance of the 4 globally common types, but a much greater strain diversity has also been identified (we now recognize strains with at least 42 P-G combinations). These studies also identified globally (G9) or regionally (G5, G8, and P2A6) common serotype antigens not covered by the reassortant vaccines that have undergone efficacy trials. The enormous diversity and capacity of human rotaviruses for change suggest that rotavirus vaccines must provide good heterotypic protection to be optimally effective.
To estimate the global illness and deaths caused by rotavirus disease, we reviewed studies published from 1986 to 2000 on deaths caused by diarrhea and on rotavirus infections in children. We ...assessed rotavirus-associated illness in three clinical settings (mild cases requiring home care alone, moderate cases requiring a clinic visit, and severe cases requiring hospitalization) and death rates in countries in different World Bank income groups. Each year, rotavirus causes approximately 111 million episodes of gastroenteritis requiring only home care, 25 million clinic visits, 2 million hospitalizations, and 352,000-592,000 deaths (median, 440,000 deaths) in children <5 years of age. By age 5, nearly every child will have an episode of rotavirus gastroenteritis, 1 in 5 will visit a clinic, 1 in 65 will be hospitalized, and approximately 1 in 293 will die. Children in the poorest countries account for 82% of rotavirus deaths. The tremendous incidence of rotavirus disease underscores the urgent need for interventions, such as vaccines, particularly to prevent childhood deaths in developing nations.
Rotavirus remains a leading cause of diarrhoeal morbidity and mortality in young children and rotavirus vaccines are critical for reducing global disease burden. This report addresses the performance ...of rotavirus vaccines in countries with high child mortality. We performed a sensitivity analysis as part of a systematic review on rotavirus vaccines to inform development of World Health Organization vaccine recommendations. The efficacy of four prequalified vaccines against severe rotavirus gastroenteritis was similar across high mortality settings in Asia and Africa. Within the first year following vaccination, vaccine efficacy for the four vaccines ranged from 48% to 57% while in the second year, efficacy ranged from 29% to 54%. The four vaccines showed no increase in intussusception risk in these settings. All four vaccines appear to prevent significant numbers of severe rotavirus gastroenteritis episodes with no measurable increase in intussusception risk in high mortality settings in Africa and Asia.
In October 2009, a new genogroup II, type 4 (GII.4) norovirus variant was identified in the United States. We collected norovirus outbreak data from 30 states to assess whether this new strain was ...associated with increased acute gastroenteritis activity. No increase in norovirus outbreaks was observed during the 2009—2010 winter.
AbstractBackgroundGlobally, rotavirus is the leading cause of acute gastroenteritis (AGE) in children aged <5 years. Botswana introduced the monovalent rotavirus vaccine (Rotarix) in July 2012. To ...study the impact of this vaccine on rotavirus genotypes circulating in Botswana, a comparison of the genotypes pre-vaccination (2011–2012) and post-vaccination (2013–2018) periods was conducted. Subjects and methodsResidual samples from 284 children <5 years of age that tested positive for rotavirus by enzyme immunoassay were genotyped. One hundred and five samples were from the pre-vaccination period and 179 were from the post-vaccination period. Genotyping was performed using two multiplexed one-step reverse transcription polymerase chain reaction (RT-PCR) assays for the amplification and genotyping of rotavirus VP7 (G) and VP4 (P) genes. ResultsPrior to vaccine introduction, the predominant rotavirus circulating genotypes were G9P8 (n = 63, 60%) and G1P8 (n = 22, 21%). During the vaccine period, G2P4 was the predominant genotype (n = 49, 28%), followed by G9P8 (n = 40, 22%) and G1P8 (n = 33, 18.5%). There was a significant decline in the prevalence of G9P8 (p = 0.001) in the post-vaccination period. There was also a notable decline in G1P8. A spike in G2P4 was observed in 2013, one year post-vaccine introduction. Rotavirus strain G3P4 (n = 8) was only detected in the post-vaccine introduction period. In 2018 there was a marked increase in genotype G3P8 (p = 0.0003). ConclusionsThe distribution of circulating rotavirus genotypes in Botswana changed after vaccine implementation. Further studies are needed to examine whether these changes are related to vaccination or simply represent natural secular variation.
Rotavirus vaccines have been introduced into over 95 countries globally and demonstrate substantial impact in reducing diarrheal mortality and diarrheal hospitalizations in young children. The ...vaccines are also considered by WHO as "very cost effective" interventions for young children, particularly in countries with high diarrheal disease burden. Yet the full potential impact of rotavirus immunization is yet to be realized. Large countries with big birth cohorts and where disease burden is high in Africa and Asia have not yet implemented rotavirus vaccines at all or at scale. Significant advances have been made demonstrating the impact of the vaccines in low- and lower-middle income countries, yet the modest effectiveness of the vaccines in these settings is challenging. Current research highlights these challenges and considers alternative strategies to overcome them, including alternative immunization schedules and host factors that may inform us of new opportunities.
Rotavirus vaccines have demonstrated significant impact in reducing the burden of morbidity and mortality from childhood diarrhoea in countries that have implemented routine vaccination to date. ...Despite this success, in many countries, rotavirus vaccine coverage remains lower than that of other routine childhood vaccines. Several issues may potentially affect vaccine uptake, namely safety concerns related to intussusception with consequent age restrictions on rotavirus vaccination, contamination with porcine circovirus, vaccine-derived reassortant strains and hospitalization in newborn nurseries at time of administration of live oral rotavirus vaccine. In addition to these safety concerns, other factors may also affect uptake, including lower vaccine efficacy in the developing world, potential emergence of strains escaping from vaccine protection resulting in lower overall impact of a vaccination programme and sustainable vaccine financing. Although further work is needed to address some of these concerns, global policy bodies have reaffirmed that the benefits of rotavirus vaccination outweigh the risks, and vaccine use is recommended globally.
Abstract Availability of new rotavirus vaccines has highlighted the need to collect local disease and economic burden data to aid decision makers at global, regional and country level. The World ...Health Organization and the GAVI Alliance recommended that generic protocols be used and that regional surveillance networks be established to collect these data, thereby helping to fast-track the introduction of these new vaccines into developing countries. Nine countries and regions participated in the first phase of the Asian Rotavirus Surveillance Network (ARSN), which collected data over a 2-year period during 2001–2003. Overall 45% of diarrhoea admissions in the region were positive for rotavirus, which was higher than had been anticipated. Significant rotavirus strain diversity was noted during the surveillance period. Data collection for a second phase of the ARSN commenced in 2004 and included a greater proportion of poorer countries that would in future be eligible for funding support for rotavirus immunization from GAVI. Limited economic evaluations in Asia have demonstrated the potential for new rotavirus vaccines to be cost-effective but more local analyses are required. Despite the ARSN's comprehensive data from a mix of developed and developing countries, Asia has lagged the Americas in terms of the introduction of rotavirus vaccines into National Immunization Programmes (NIPs). Lack on rotavirus vaccine efficacy data in Asia, particularly in poorer populations, will have contributed to this delay. Thus ensuring that all global regions are simultaneously involved in the evaluation of new vaccines from the beginning and also encouraging more regional collaborations of Ministry of Health representatives could help to accelerate the introduction of new vaccines into NIPs.
Rotavirus Vaccines in Routine Use Tate, Jacqueline E.; Parashar, Umesh D.
Clinical infectious diseases,
11/2014, Letnik:
59, Številka:
9
Journal Article
Recenzirano
Odprti dostop
Vaccines are now available to combat rotavirus, the most common cause of severe diarrhea among children worldwide. We review clinical trial data for available rotavirus vaccines and summarize ...postlicensure data on effectiveness, impact, and safety from countries routinely using these vaccines in national programs. In these countries, rotavirus vaccines have reduced all-cause diarrhea and rotavirus hospitalizations by 17%–55% and 49%–92%, respectively, and all-cause diarrhea deaths by 22%–50% in some settings. Indirect protection of children who are age-ineligible for rotavirus vaccine has also been observed in some high and upper middle income countries. Experience with routine use of rotavirus vaccines in lower middle income countries has been limited to date, but vaccine introductions in such countries have been increasing in recent years. The risk-benefit analysis of rotavirus vaccines is extremely favorable but other strategies to improve the effectiveness of the vaccine, particularly in lower middle income settings, should be considered.
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