We report an ongoing measles outbreak in Greece. The first cases were notified through the mandatory notification system on May 2017 in Northern Greece and concerned a cluster of three imported cases in unvaccinated Roma siblings. So far, 3150 cases have been reported in all 13 Regions. Initially, the outbreak mainly affected Greek Roma but as it progressed it spread to non-minority Greek nationals. The outbreak reached its ultimate peak on week 10/2018 but from week 15/2018 has been gradually declining. Most cases (60.6%) were Roma (especially children <10 year-old) followed by non-minority Greek nationals (29.3%; mostly young adults). The majority (80.4%) were unvaccinated. Interestingly, 129 (4.1%) cases were healthcare workers (HCWs). Genotype B3 was identified by molecular methods in all 87 cases tested. Overall, 61.3% of the cases were hospitalised. Complications were reported in 17.1% of the cases among which four deaths. The outbreak occurred after 3 years without local endemic measles transmission. Extensive vaccination implemented as the major public health measure managed to prevent the emergence of a large number of cases in refugee/migrant hosting sites. Mitigation efforts currently focus on raising awareness among HCWs and closing the immunisation gap in populations with suboptimal vaccination coverage.

In the context of poliomyelitis eradication, a reinforced supplementary laboratory surveillance of enteroviruses was implemented in Greece. Between 2008 and 2014, the Hellenic Polioviruses/Enteroviruses Reference Laboratory performed detailed supplementary surveillance of circulating enteroviruses among healthy individuals in high-risk population groups, among immigrants from countries in which poliovirus is endemic, and in environmental samples. In total, 722 stool samples and 179 sewage water samples were included in the study. No wild-type polioviruses were isolated during these 7 years of surveillance, although two imported vaccine polioviruses were detected. Enterovirus presence was recorded in 25.3 and 25.1% of stool and sewage water samples, respectively. Nonpolio enteroviruses isolated from stool samples belonged to species A, B, or C; coxsackievirus A24 was the most frequently identified serotype. Only enteroviruses of species B were identified in sewage water samples, including four serotypes of echoviruses and four serotypes of coxsackie B viruses. Phylogenetic analysis revealed close genetic relationships among virus isolates from sewage water samples and stool samples, which in most cases fell into the same cluster. To the best of our knowledge, this is the first study to compare enterovirus serotypes circulating in fecal specimens of healthy individuals and environmental samples, emphasizing the burden of enterovirus circulation in asymptomatic individuals at high risk. Given that Greece continues to receive a large number of short-term arrivals, students, migrants, and refugees from countries in which poliovirus is endemic, it is important to guarantee high-quality surveillance in order to maintain its polio-free status until global eradication is achieved. IMPORTANCE This article summarizes the results of supplementary poliovirus surveillance in Greece and the subsequent characterization of enteroviral circulation in human feces and the environment. The examination of stool samples from healthy refugees and other individuals in "high-risk" groups for poliovirus enables the identification of enterovirus cases and forms the basis for further investigation of the community-level risk of viral transmission. In addition, the examination of composite human fecal samples through environmental surveillance links poliovirus and nonpoliovirus isolates from unknown individuals to populations served by the sewage or wastewater system. Supplementary surveillance is necessary to comply with the prerequisites imposed by the World Health Organization for monitoring the emergence of vaccine-derived polioviruses, reemergence of wild polioviruses, or disappearance of all vaccine-related strains in order for countries such as Greece to maintain their polio-free status and contribute to global poliovirus eradication.

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BackgroundMeasles is a highly contagious disease which still remains a cause of severe complications, including deaths worldwide, despite the existence of safe and effective vaccines. In the last 3 decades, the incidence of measles in Greece has constantly declined with only sporadic clusters or outbreaks (last outbreak in 2010–2011). We describe the characteristics of the ongoing measles outbreak and the Public Health response.MethodsAll measles cases are reported through the mandatory notification system (EU case definition 2012) to the Department of Surveillance and Intervention of the Hellenic Centre for Disease Control and Prevention. For laboratory confirmation patient sera were tested for IgM antibodies and pharyngeal swabs for the presence of measles virus RNA with RT-PCR. Sequencing of the measles nucleoprotein gene was applied in positively tested serological samples.ResultsFrom 9 May 2017 to 26 April 2018, 2,659 cases were reported in all 13 regions in Greece; 1,605 (60.4%) were laboratory confirmed. Most cases (n = 1,595; 60%) were Roma (73% children <10 years) followed by nonminority Greek nationals (n = 781; 29.4%, of whom 57% young adults 25–44 years), highlighting the immunity gap in Roma population. The vast majority of cases (80.5%) were unvaccinated. Ninety-four (3.5%) cases were healthcare workers (HCW); all were partially or not vaccinated. Genotype B3 was identified by molecular testing in all 88 cases tested. Severe complications were reported in 429 (16.1%) patients, most frequently pneumonia (43.8%) and hepatitis (21.2%). Three deaths were recorded in an 11-month-old immunocompromised Roma infant, a 17-year-old unvaccinated Roma, and a 35 year olds partially vaccinated individual from the general population. Extensive vaccination in refugee/migrant hosting sites prevented the emergence of a large number of cases. Mitigation efforts focused on closing the immunization gap in Roma population through emergency vaccination and raising awareness among HCWs to prevent further spread.ConclusionThe current outbreak highlights the need to achieve high vaccination coverage with 2 doses of MMR vaccine in the general population (children, adolescents, and young adults) and in hard-to-reach vulnerable populations like Roma and refugees.Disclosures All authors: No reported disclosures.