Article History
Received: 6 November 2017
Accepted: 26 March 2018
First Online: 10 April 2018
Ethics approval and consent to participate
: The study is based on surveillance data and as such does not necessitate approval of Ethical Committee. Collection of data on communicable diseases as part of epidemiological surveillance is carried out by the State Sanitary Inspection and NIPH-NIH according to the existing legislation: Act of 5th December 2008 on the Prevention and Control of Infections and Infectious Diseases in Humans [CitationRef removed].
: Not applicable.
: The authors declare that they have no competing interests.
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