[1] UNIV MARYLAND HOSP, CTR VACCINE DEV, DIV UNDERGRAD PEDIAT EDUC, BALTIMORE, MD 21201 USA
[2] UNIV MARYLAND HOSP, CTR VACCINE DEV, DEPT PEDIAT, DIV GEOG MED, BALTIMORE, MD 21201 USA
[3] UNIV MARYLAND HOSP, CTR VACCINE DEV, DEPT MED, BALTIMORE, MD 21201 USA