Gunmen opened fire on a World Health Organization (WHO) vehicle in Pakistan's southern seaport of Karachi on July 17.
Officials said the shooting wounded a foreign doctor working on a polio immunization campaign and a local driver.
The shooting happened in the impoverished Soharb Ghoth neighborhood.
WHO says the two men are in stable condition in a private hospital.
The Geneva-based agency said there is no evidence to suggest that this was a targeted attack against polio eradication efforts or the WHO.
Pakistan is in the second day of a three-day campaign to vaccinate children under 5.
Taliban militants in northern Pakistan have banned the vaccination, saying it can't go forward until the United States stops drone strikes in Pakistan.
Based on reporting by AP, AFP, and Reuters