[1] Ctr Dis Control & Prevent, Div Viral & Rickettsial Dis, Natl Ctr Infect Dis, Atlanta, GA 30333 USA
[2] Pan Amer Hlth Org, Caribbean Epidemiol Ctr Lab, Port of Spain, Trinidad Tobago
[3] PAHO, Div Vaccines & Immunizat, Washington, DC 20037 USA
[4] Minist Hlth, Santo Domingo, Dominican Rep
[5] Minist Publ Hlth, Port au Prince, Haiti
[6] Ctr Dis Control & Prevent, Vaccine Preventable Dis Eradicat Div, Natl Immunizat Program, Atlanta, GA 30333 USA
[7] PAHO, Santo Domingo, Dominican Rep
[8] PAHO, Port au Prince, Haiti
[9] Natl Inst Infect Dis, Dept Virol 2, Shinjuku Ku, Tokyo 162, Japan
[10] Natl Inst Publ Hlth & Environm, Polio Lab, RIVM, NL-3720 BA Bilthoven, Netherlands