Search

Rotaviruses bind to enterocytes in a genotype-specific manner via histo-blood group antigens (HBGAs), which are also detectable in saliva. We evaluated antirotavirus immunoglobulin A seroconversion ('vaccine take") among 166 Ghanaian infants after 2-3 doses of G1P[8] rotavirus vaccine during a vaccine trial, by HBGA status from saliva collected at age 4.1 years. Only secretor status was associated with seroconversion: 41% seroconversion for secretors vs 13% for nonsecretors; relative risk, 3.2 (95% confidence interval, 1.2-8.1; P = .016). Neither Lewis antigen nor salivary antigen blood type was associated with seroconversion. Likelihood of "take" for any particular rotavirus vaccine may differ across populations based on HBGAs., (Published by Oxford University Press for the Infectious Diseases Society of America 2018.)

Background: Oral rhesus/rhesus-human reassortant rotavirus tetravalent vaccine (RRV-TV) was licensed in 1998 but withdrawn in 1999 due to a rare association with intussusception, which occurred disproportionately in infants receiving their first dose at ≥90 days of age. This study examined RRV-TV for the prevention of rotavirus gastroenteritis (RV-GE) in Ghana, West Africa, with infants receiving the first dose during the neonatal period and the second before 60 days of age., Methods: In a double-blinded, randomized, placebo-controlled trial in Navrongo, Ghana, we recruited neonates to receive 2 doses of RRV-TV or placebo and followed them to age 12 months., Results: In the intention-to-treat population of 998 infants, we measured a vaccine efficacy of 63.1% against RV-GE of any severity associated with any of the 4 serotypes represented in the vaccine and 60.7% against RV-GE associated with any rotavirus serotype., Conclusions: RRV-TV in a 2-dose schedule with the first dose during the neonatal period is efficacious in preventing RV-GE in rural Ghana. Neonatal dosing results in early protection and may be the optimum schedule to avoid or significantly reduce intussusception, now reported to be associated in international settings with the 2 most widely marketed, licensed, live virus, oral rotavirus vaccines.

Rotavirus remains a priority candidate for vaccine development, because it is the major cause of viral diarrhea in children worldwide. This study characterized rotavirus strains in 195 stool specimens collected from children <5 years of age with diarrhea, in the Southwest Province and Western Province of Cameroon during 1999-2000. The predominant G type was G1 (detected in 44.9% of specimens) and the most predominant P type was P[8] (in 82.7%). The most common G-P combination detected was G1P[8] (in 37.1% of specimens), followed by G9P[8] (in 14%). Rotavirus strains with unusual G-P combinations, such as G1P[4], G2P[8], G8P[8], G9P[4], G5P[8], and G10P[8], were also observed in significant numbers. Analysis of the age distribution showed that G1P[8] was found circulating in all age groups except in infants <6 months old. Strains G2P[4] and G3P[8] were identified in children >37 months and 19-24 months of age, respectively. Strain G9P[8] was found circulating among children >25 months of age. Unusual strains and mixed infections were found circulating in the different age groups, albeit at lower levels. The high prevalence of mixed infections and diversity of rotavirus strains detected in this first study based on genotyping of Cameroonian strains reinforce the need to continue with surveillance programs in Africa, where a high diversity of strains has been reported.

Severe rotavirus diarrhea in children <5 years of age is a major public health problem; however, limited regional and country specific data on rotavirus disease burden are available from sub-Saharan Africa. In June 2006, the World Health Organization Regional Office for Africa initiated rotavirus surveillance in selected African countries. With use of standardized methodology developed by the World Health Organization, children <5 years of age who were hospitalized with severe diarrhea were enrolled, and stool specimens were collected for detection of rotavirus strains with use of a commercial enzyme immunoassay. Rotavirus strains were further characterized for G and P types with use of a reverse-transcriptase polymerase chain reaction. From June 2006 through December 2008, rotavirus surveillance was established at 14 sites in 11 African countries. Of 5461 stool samples collected from children enrolled in 8 countries with 1 or 2 complete years of data, 2200 (40%) were positive for rotavirus. Ninety percent of all rotavirus hospitalizations occurred among children aged 3-12 months. Predominant types included G1P[8] (21%), G2P[4] (7%), and P [8] (29%); however, unusual types were also detected, including G8P[6] (5%), G8P[8] (1%), G12P[6] (1%), and G12P[6] (1%). A high percentage of mixed rotavirus infections was also detected. These preliminary results indicate that rotavirus is a major cause of severe diarrheal disease in African children.

During routine rotavirus surveillance projects in Cameroon and Cote d'Ivoire, 2 fecal samples collected from 2 children <5 years of age who presented with symptoms of gastroenteritis were found to give anomalous G typing results. These specimens were strongly rotavirus positive by enzyme immunoassay, displayed VP6 subgroup II specificity and long RNA electropherotypes, and were typed as rotavirus serotype G2 with monoclonal antibodies. In addition, the strains were typed as rotavirus VP7 genotype G3 and VP4 genotype P[8] by reverse-transcription polymerase chain reaction. Further investigation of the polymerase chain reaction G-typing results with a second set of primers revealed that the specimens were not genotype G3, and both samples were sequenced to elucidate the problem. Both strains were found to be genotype G10 by nucleotide sequence. Comparison of nucleotide and amino acid sequences and phylogenetic analysis of the African G10 strains revealed that these strains are closely related to the human G10 strains that were detected during the 2001-2003 rotavirus season in Ghana. The detection of G10 rotavirus in Africa adds to the global distribution of this strain and strengthens the need to continue strain surveillance in developing countries to understand the extent of strain distribution and diversity.

From October 2003 through September 2004, a total of 289 stool samples were collected from children <5 years of age who had severe diarrhea at admission to or when visiting the emergency department at the Navrongo War Memorial Hospital in rural Ghana during a study on rotavirus disease burden. Rotavirus antigen was detected in 115 stool samples (39.8%) tested for rotavirus. Four rotavirus-positive samples were found to bear G10P[6] specificity by reverse-transcription polymerase chain reaction, polymerase chain reaction-enzyme-linked immunosorbent assay, and oligonucleotide microarray hybridization. Two of these strains further exhibited serotype G10 specificity by neutralization and subgroup II specificity by enzyme immunoassay and possessed long electropheretic patterns by polyacrylamide gel electrophoresis. Their VP7 genes shared a much closer nucleotide identity with other African human G10 strains (>97%) than with human G10 strain from Asia or South America (<86%) or animal strains (<85%). The VP8* genes of the Ghanaian G10 strains exhibited >94% identity to that of human P[6] virus strains and belonged to the P[6] lineage 1a. The deduced VP7 amino acid sequence showed that the Ghanaian strains were more closely related to human G10 strains than to animal G10 strains. The possession of the typical human subgroup II specificity and the P[6] specificity (frequently found in Ghana and the rest of Africa) and the marked similarity in the VP7 antigenic sites suggest that these G10 strains may have evolved through genetic reassortment between bovine and human strains.