"As refugees and migrants move, inter-country coordination must be strengthened across the European region, as well as with the countries of origin and transit," WHO European director Zsuzsanna Jakab said in a statement.
The migrant influx "calls for a regional, comprehensive and systematic public health response," she said following a WHO European regional meeting in the Lithuanian capital Vilnius.
More than 430,000 people fleeing war, poverty and persecution have crossed the Mediterranean to reach Europe this year, with nearly 2,800 dying en route or going missing, according to the International Organization for Migration.
The United Nations agency said it would hold a high-level conference soon "to agree on a common public health approach to large-scale migration" in Europe.
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The health body dismissed widespread concerns that migrants would import infectious diseases, noting that not a single case of Ebola was brought into Europe by refugees or migrants.
Severoni said sick individuals would be unable to undertake the often arduous journey to a new life in Europe.