Rotavirus

Rotavirus is the leading cause of severe, dehydrating diarrhea in children less than 5 years old. Rotavirus is a non-enveloped, double-stranded RNA virus belonging to the family Reoviridae. It has a triple-shelled virion containing a genome of eleven segments. These segments encode for six viral structural proteins (VP1–VP4, VP6 and VP7) and six non-structural proteins (NSP1–NSP6). Each genome segment (with the exception of gene 11 encoding for NSP5 and NSP6) codes for a single viral protein. The VP4 (P) and VP7 (G) proteins found on the surface of the virion are the targets of neutralizing antibodies and are of the greatest current interest with respect to vaccine development. The inner protein VP6 has also been considered and is the target of most enzyme-linked immunosorbent assay (ELISA)-based antibody assays. The G and P proteins are classified on the basis of their antigenic and molecular properties. Overall, at least 36 G types and 51 P types have been recognized, of which six G types (G1, G2, G3, G4, G9 andG12) and three P types (P4, P6 and P8) are those most commonly found in human infections. The distribution of genotypes varies from region to region and to some extent over time.

Following infection, a large amount of virus is shed in the stools and vomit with transmission occurring mainly by subsequent oral ingestion of contaminated materials. The vast majority of children are infected before the age of 3 years, and in most developing countries before the first birthday. The universal occurrence of rotavirus infections indicates that unlike many infectious diseases spread by fecal contamination, clean water supplies and good hygiene do not significantly lower the transmission rate.

Rotavirus Vaccines

Vaccine development has focused on live attenuated rotavirus strains of human or animal origin which mimic those found in human disease. Live attenuated rotavirus vaccines have been developed using a range of strategies. The strains from which they have been derived include human isolates with minimal manipulation or animal viruses (bovine, ovine or other) (the Jennerian approach). Some vaccines have been monovalent (containing for example only the G1, G9 or G10 type) while others have been multivalent (containing for example the G1, G2, G3, G4 and G9 types). One strategy has been to exploit the segmented nature of the rotavirus genome to generate reassortants expressing the desired G type on a common core genotype. Monovalent and multivalent vaccines covering a range of serotypes have been successfully used in clinical trials and in vaccination programmes.

Rotavirus Vaccine Standardization

Written Standards

The first WHO Guidelines to assure the quality, safety and efficacy of live attenuated rotavirus vaccines (oral) were adopted on the recommendation of the WHO Expert Committee on Biological Standardization and published in 2007. In light of developments and experience since then in various fields and aspects, WHO has revised and updated the Guidelines following public consultation process. The final Recommendations to assure the quality, safety and efficacy of rotavirus vaccines were adopted on the recommendation of the eightieth meeting of the WHO Expert Committee on Biological Standardization, 7–11 October 2024.

Recommendations to assure the quality, safety and efficacy of rotavirus vaccines (Replacement of Annex 3 of WHO Technical Report Series, No. 941)

Reference materials

No WHO reference materials for rotavirus vaccines are currently available. Due to the diversity of rotavirus vaccines produced by different manufacturers it is unlikely that international reference materials will be suitable for the standardization of assays across all rotavirus vaccine products. Manufacturers should establish product-specific reference preparation(s).

Prequalified rotavirus vaccines

Rotavirus vaccines are prequalified for procurement by UN organizations:

From March 2016 there is a new system for display of WHO prequalified vaccines

List of Prequalified Vaccines

Find out more about the new listing and how to search and display the list on the link below.

1 March 2016

Web Listing of WHO Prequalified Vaccines