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Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
Different phases of the study (green hexagons), number and type of serological assays performed (green rectangles), and number of ongoing infections revealed via rhino-pharyngeal swabs (RPS, red rhombus).