Rotavirus Strain Surveillance in the Vaccine Era: Why should we characterize

strains?

Jon Gentsch, Carl Kirkwood, George Armah, Jim Gray, Miren Iturriza-Gomara, Nicola Page, Duncan Steele,

Mathew Esona, May El Sherif and Roger Glass

Centers for Disease Control and Prevention, Atlanta, USA; Murdoch Childrens Research

Institute, Melbourne, Australia; NMIMR, University of Ghana, Legon; Health Protection Agency,

London, United Kingdom; Medical University of South Africa, Pretoria, South Africa

Importance of Rotavirus Strain Surveillance and Molecular

Epidemiology

Vaccine Research- serotypes of vaccines- impact of vaccine on strains- reassortment of vaccine in vivo

Virus Evolution- origin of new strains- animal rotavirus role- reassortment between strains- genetic variation in RV genes

Rotavirus Surveillance Studies

• Lessons learned in pre-vaccine era• Goals of surveillance during vaccine

program implementation • Reference lab activities supporting

surveillance programs

Rotavirus StructureRNA

Segment Protein

1234

5

6

78

9

10

11

VP1VP2VP3VP4

NSP1

VP6

NSP2

NSP3

VP7

NSP4

NSP5

VP2

VP4 Neutralization

antigen

VP6Subgroupantigen

VP7Neutralization

antigen

Subcore

P[8]G47.5%

P[8]G152.2%

other18.2%

P[8]G32.8%

P[4]G211.5%

Lessons from Surveillance: 1. Limited Number of Globally Common Strains

N=21,256 (1993-2003)Gentsch et al, JID, 2005

Rare or regionally common strains (25 strainstotal): P[4]G1 (1.3%), P[6]G2 (0.8%), P[6]G1 (0.6%), P[6]G8 (0.6%), P[4], G3 (0.5%)

5.5%

Lessons from Surveillance: 2. Large Variation in Strain Incidence between Developed and

Developing Regions

P[6]G1 or G24%

P[6]G210%

P[8]G119%

other28%

P[8]G42%

P[8]G38%

P[4]G23%

P[8]G96%

P[6]G810%

P[8]G91% P[4]G1

1%

other15%

P[8]G412%

P[8]G32%

P[4]G29% P[8]G1

60%

Europe Africa

N=6328

Gentsch et al, JID, 2005

N=1147

6[1]

US58512

Mc35I32110

Mc323116EUS1205

WI619

HAL1166

69MMW023MW3338

PA169PA1516

Br10545

ST-3Hochi4

157CHCR3AU-1McN13107E1BP3

1076DS-12

K8AU19M37AU64Wa1

12[19]11[14]8[11]5A[3]4[10]3[9]2C[6]2A[6]1B[4]1A[8]G type

Lessons from Surveillance: 3. Extensive Serotype Diversity and Reassortment

P serotype [genotype]

Globally Common UncommonRegionally Common Neonates Gentsch et al, JID, 2005

Genotypic Properties (gene segment):

G type P type (4) Subgroup (6) PAGE pattern (11)

No of strains

9 8 II Long 1

9 6 I Short 32

9 6 I, II Long 5

9 8 I Short 9

9 0 ND Short 6

9 0 ND Long 3

Distribution of natural RV G9 reassortants in Bangladesh

Unicomb, et al. 1999

Reassortment in Multiple Gene Segments

Lessons from Surveillance: 4. Emergence of Serotype G9 (1995-2005)

First reports, mid 1980sG9 reports - late 1980s through 2005

Philadelphia, 83 Osaka, 85

Surveillance goals during and after implementation of vaccine programs?

• Breakthrough strains that appear after vaccination

• Changes in serotype incidence and the emergence of novel strains with distinct G and P serotypes

• Circulation of vaccine strains in children• Reassortment with wild-type human

rotaviruses, yielding new strains or changes in virulence

What kind of breakthrough strains might occur after Vaccination with Rotarix and

Rotateq?

G1P1A[8]

G1 G3

G2 G4

P1A[8]

Human rotavirus

Bovine rotavirus with single human rotavirus gene

substitution

GSK Bio(Rotarix)

Merck(Rotateq)

HighHighP[8], G4HighHighP[8], G9HighReducedP[4], G2

HighHighP[8], G3HighHighP[8], G1

Rotateq**(P[8], G1-G4)

Rotarix (P[8]G1)Infecting strain

Efficacy

**Only G types of infecting strains reported

Adapted from Vesikari et al and Ruiz-Palacios et al, N Engl J Med: 354, 2006

Efficacy of Licensed Rotavirus Vaccines

Other Strains with Reduced Efficacy or Failure?

1

111098765432

111098765432

P[8]G1 P[8]G3 P[8]G4 P[8]G9 P[4]G2 P[6]G9Rotarix

VP4 (P)

VP6

VP7 (G)NSP4

P[8]G1

High efficacyReducedEfficacy

Wa genogroupDS-1 genogroup

Within genogroups - high genetic homology and antigenic relatednessBetween genogroups – lower genetic homology and antigenic relatedness

Efficacy?

P[6]G12

Potential Breakthrough Strains with Rotateq

P[6]G9 P[6]G12

Wa HRV genogroupDS-1 HRV genogroupAU-1 HRV genogroup

P[8]

G1 G2 G3 G4

Bovine genogroup

Strains from the United StatesP[9]G6

Circulation of Vaccine Strains and Reassortment with HRV

• Rotarix – expect reassortment with natural RV (P[8]G1, P[8]G9,etc) during mixed infections– Reassortment in all 11 genes likely

• Rotateq?• Potential to produce new strains with

altered virulence – important surveillance issue

123

45678

91011

Genogroup Specificity

WaDS1

Segments

High Throughput Techniques are neededTo Study Reassortment in all Genes:Gene Segment Typing by Microarray

ab c d e f g h i j

Wa WaDS1 DS1

B223/Bov

Strain 116e

P[8]G1

P[4]G2

Strain 116e

P[8]G1

P[4]G2

Strain 116e

B223/BovVP4

VP7 B223/Bov

NSNS

Rotavirus Reference Centersand Collaborating Centers

• Supported by WHO and PATH• Set up to support surveillance networks• Provide training, protocols, reagents and

assistance• Prepared a unified lab manual of rotavirus

characterization protocols

Rotavirus Reference Centersand Collaborating Centers

WHO Collaborating CenterCDC, Atlanta

WHO Collaborating CenterMurdoch Childrens Research InstituteMelbourne

South African Reference CenterMEDUNSAPretoria

West African Reference CenterNMIMR, Univ. of GhanaLegon

United Kingdom Reference CenterHealth Protection AgencyLondon

MANUAL OF ROTAVIRUS CHARACTERIZATION METHODS

Draft Version

This document was produced by the Laboratory Directors of the European, West African, and South African Rotavirus Reference Laboratories, and the WHO Rotavirus Collaborating Centers in Melbourne, Australia, and

Atlanta, Georgia, United States

Copies may be requested from:

Jim GrayHealth Protection AgencyLondon, United KingdomJim.Gray@HPA.org.uk

George ArmahWest African Reference CenterNMIMR, Univ. of GhanaLegonGArmah@noguchi.mimcom.net

Nicola PageSouth African Reference CenterMEDUNSAPretoriapagenic@medunsa.ac.za

Carl KirkwoodWHO Collaborating CenterMurdoch Childrens Research InstituteMelbournecarl.kirkwood@mcri.edu.au

Jon GentschWHO Collaborating CenterCDC, Atlantajgentsch@cdc.gov

Summary• Rotavirus strain surveillance and

characterization studies have played key role in defining serotypes important for vaccines and understanding strain diversity and mechanisms of evolution

• During and after vaccine programs are implemented surveillance will be crucial to monitor changes in serotypes and vaccine effectiveness