The World Health Organization (WHO) said Thursday that it was planning emergency vaccination campaigns along the border between Angola and Congo amid the worst yellow fever outbreak in decades that already is blamed for more than 400 deaths. The vaccination efforts next month also will focus on the Congolese capital, Kinshasa, where experts fear that the disease could quickly spread in congested neighborhoods. The outbreak has led to cases in Kenya and China as well, via travelers. "While WHO is working with partners and vaccine manufacturers to increase vaccine production and replenish the emergency stockpile currently being used for this outbreak, it is vital to interrupt transmission, especially in cross-border areas to rapidly bring this outbreak under control and halt further international spread," WHO Regional Director for Africa Dr. Matshidiso Moeti said.