G and P Types of Circulating Rotavirus Strains in the United States during 1996–2005: Nine Years of Prevaccine Data

BackgroundRotavirus vaccine was recommended for routine use among US infants in 2006. To provide prevaccine data, we conducted strain surveillance for 9 consecutive seasons during 1996–2005 MethodsUsing reverse-transcriptase polymerase chain reaction genotyping and nucleotide sequencing, we determined P/G genotypes of >3100 rotavirus strains collected in up to 12 cities each year from different US regions ResultsThe most prevalent strain globally, P[8] G1, was the most prevalent each year in the United States (overall, 78.5% of strains; range, 60.0%–93.9%), and 9.2% of the samples were P[4] G2, 3.6% were P[8] G9, 1.7% were P[8] G3, and 0.8% were P[8] G4. Genotype P[6] G9, which emerged in 1995, was detected continuously for several seasons (from 1996–1997 to 2000–2001, 0.2%–5.4%) but was not identified in the subsequent 4 seasons. Single or a few detections of rare genotypes (eg, P[6] G12, P[9] G6, and P[9] G3) were observed during several rotavirus seasons at frequencies of 0.5%–1.7% and, overall, comprised 0.6% of all the samples from the entire surveillance period. Several globally common strains in addition to G1, especially G2 and G9, circulated at high prevalence (33%–62%) in some cities during certain years ConclusionsAlmost 85% of strains during 1996–2005 had either a G or P antigen that is present in both RotaTeq (Merck) and Rotarix (GlaxoSmithKline). Monitoring of strains after introduction of rotavirus vaccines is important