Success of rotavirus vaccination in Africa: good news and remaining questions
Authors: Timo Vesikari
Journal: The Lancet Global Health (2016)

The study by Fidele Ngabo and colleagues in The Lancet Global Health1Ngabo F Tate JE Gatera M et al.Decline in diarrhea and rotavirus hospitalizations following introduction of pentavalent rotavirus vaccine in Rwanda.Lancet Glob Health. 2016; 4: e129-e136Summary Full Text Full Text PDF Scopus (50) Google Scholar shows the feasibility of the successful introduction and large effect of rotavirus vaccination in Rwanda. The findings are a tribute not only to rotavirus vaccination but also to the RotaTeq (so-called pentavalent or RV5) vaccine because Rwanda has used this vaccine exclusively in its immunisation programme. Several African countries have introduced rotavirus vaccination using the human rotavirus vaccine Rotarix and good effectiveness has been reported from South Africa2Groome MJ Page N Cortese MM et al.Effectiveness of monovalent human rotavirus vaccine against admission to hospital for acute rotavirus diarrhoea in South African children: a case-control study.Lancet Infect Dis. 2014; 14: 109-204Summary Full Text Full Text PDF PubMed Scopus (104) Google Scholar and Malawi.3Bar-Zeev N Kapanda L Tate JE et al.Effectiveness of a monovalent rotavirus vaccine in infants in Malawi after programmatic roll-out: an observational and case-control study.Lancet Infect Dis. 2015; 15: 422-428Summary Full Text Full Text PDF PubMed Scopus (130) Google Scholar The real-life effectiveness of RotaTeq in Rwanda was recorded in several ways and is convincing. After the introduction of rotavirus vaccination in 2012, admittance to hospital for gastroenteritis decreased by 49% in 2013, and 48% in 2014, and admittance to hospital for rotavirus in the hospitals doing specific rotavirus diagnosis decreased by 61% and 70% in the same period. The effectiveness is actually in line with the available prelicensure efficacy data for RotaTeq in Kenya (83%) and Ghana (65%) against severe rotavirus gastroenteritis severity score (the Vesikari score) of 11/20.4Armah GE Sow SO Breiman RF et al.Efficacy of pentavalent rotavirus vaccine against severe rotavirus gastroenteritis in infants in developing countries in sub-Saharan Africa: a randomised, double-blind, placebo-controlled trial.Lancet. 2010; 376: 60-74Summary Full Text Full Text PDF Scopus (578) Google Scholar, 5Madhi SA Cunliffe NA Steele D et al.Effect of human rotavirus vaccine on severe diarrhea in African infants.N Engl J Med. 2010; 362: 289-298Crossref PubMed Scopus (18) Google Scholar It is impressive that, according to the report of Ngabo and colleagues, Rwanda has reached a coverage rate of 98–99% for rotavirus vaccination. Although it does not specify whether this meant all three doses, the study shows that RotaTeq vaccination is compatible with the Expanded Programme on Immunization (EPI) dosing at 6, 10, and 14 weeks of age and that a three-dose vaccine (and not only two-dose Rotarix) can successfully be given in Africa. Three doses might be better than two because durable immunity against rotavirus depends on the number of hits, whether vaccination or natural infection,6Velazquez FR Matson DO Calva JJ et al.Rotavirus infections in infants as protection against subsequent infections.N Engl J Med. 1996; 335: 1022-1028Crossref PubMed Scopus (738) Google Scholar although the two-dose Rotarix has also shown good protection in Africa. The report contains no information about rotavirus serotypes in Rwanda. This is not that important though because for practical purposes surveillance of rotavirus serotypes is becoming obsolete as it has been convincingly shown that the efficacy and effectiveness of rotavirus vaccines against severe rotavirus gastroenteritis are not serotype-specific. Thus, the pentavalent and monovalent vaccines are at the same start line.7Leshem E Lopman B Glass R et al.Distribution of rotavirus strains and strain-specific effectiveness of the rotavirus vaccine after its introduction: a systematic review and meta-analysis.Lancet Infect Dis. 2014; 14: 847-856Summary Full Text Full Text PDF PubMed Scopus (151) Google Scholar As an example, the 49% efficacy of Rotarix in Malawi was the same against various rotavirus G-types that were recorded during the trial.5Madhi SA Cunliffe NA Steele D et al.Effect of human rotavirus vaccine on severe diarrhea in African infants.N Engl J Med. 2010; 362: 289-298Crossref PubMed Scopus (18) Google Scholar If the performance of rotavirus vaccines in Africa is not as good as in developed countries, it is not because there are more diverse rotavirus serotypes circulating in Africa. Although the effectiveness of rotavirus vaccine in Rwanda is high and is promising, the effectiveness is still less than in developed countries. For example, in Finland, with equally high coverage, the effect of rotavirus vaccination has been an 88% reduction of admittances to hospital for rotavirus gastroenteritis, with most of the remaining cases occurring in older children who have been too old to be vaccinated in the programme, and very few breakthrough cases of severe rotavirus gastroenteritis in vaccinated children, and even those mostly in partially vaccinated children.8Hemming M Räsänen S Huhti L Paloniemi M Salminen M Vesikari T Major reduction of rotavirus, but not norovirus, gastroenteritis in children seen in hospital after the introduction of RotaTeq vaccine into the National Immunization Programme in Finland.Eur J Pediatr. 2013; 172: 739-746Crossref PubMed Scopus (159) Google Scholar Such information from Rwanda (and other African countries) is missing, and future studies should address the effectiveness of RotaTeq vaccine after complete and incomplete series of vaccinations. An interesting finding in the study of Ngabo and colleagues was that, after a huge drop in the number of admittances to hospital for rotavirus in 2013, there was no further fall the next year. As the researchers discuss, this finding might herald the beginning of a biennial pattern of rotavirus activity in Africa after universal rotavirus vaccination—a phenomenon that has been seen in the USA for several years.9Payne DC Boom JA Staat MA et al.Effectiveness of pentavalent and monovalent rotavirus vaccines in concurrent use among US children <5 years of age, 2009–2011.Clin Infect Dis. 2013; 57: 13-20Crossref PubMed Scopus (137) Google Scholar Another epidemiological change in the USA has been a shift of the rotavirus epidemic season towards a later onset. Perhaps the data from Rwanda can be read to suggest that this might be also happening in an African country that has a very clear seasonal pattern of rotavirus activity. Altogether, the experience of the first 2 years of rotavirus vaccination in Rwanda can be summarised as a success. But does this success come at a price? The present report does not even mention intussusception or give any information about compliance with the EPI schedule. The WHO position towards rotavirus vaccination in Africa has been that in the interest of better coverage the timing of the first dose can be extended up to 6 months of age.10WHO position paperRotavirus vaccines.Wkly Epidemiol Rec. 2013; 88: 4-64Google Scholar It is recognised that this could increase the risk of intussusception. It would be important to document how well African countries can adhere to the recommended EPI schedule of 6, 10, and 14 weeks, because, if adhered to, such early administration could rather decrease or even minimise the risk. The report from Rwanda does not address this point, and further information is awaited. I received personal fees for being on the advisory board for SP-MSD and lecture fees from GlaxoSmithKline. Effect of pentavalent rotavirus vaccine introduction on hospital admissions for diarrhoea and rotavirus in children in Rwanda: a time-series analysisThe number of admissions to hospital for diarrhoea and rotavirus in Rwanda fell substantially after rotavirus vaccine implementation, including among older children age-ineligible for vaccination, suggesting indirect protection through reduced transmission of rotavirus. These data highlight the benefits of routine vaccination against rotavirus in low-income settings. Full-Text PDF Open Access