Challenging measles case definition: three measles outbreaks in three Health Regions of Portugal, February to April 2018

Augusto, Gonçalo Figueiredo; Cruz, Diogo; Silva, Andreia; Pereira, Natália; Aguiar, Bárbara A; Leça, A; Serrada, Elisabete; Valente, Paula; Fernandes, Teresa; Guerra, Fernando; Palminha, Paula; Vinagre, Elsa; Lopo, Sílvia; Cordeiro, Rita; Sáez-López, Emma; Neto, Maria Teresa; Nogueira, Paulo; Freitas, Graça

doi:10.2807/1560-7917.es.2018.23.28.1800328

Cited by 12 publications

(16 citation statements)

References 10 publications

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“…Our observation is in accordance with other recent reports of outbreaks in areas with high vaccination coverage [11,25]. We propose that individuals with breakthrough infection of measles can be identified with a fast provisional classification using routine laboratory testing of IgG at or after onset of rash.…”

Section: Discussionsupporting

confidence: 92%

“…In areas with high vaccination coverage, it has been estimated that the majority of cases in an outbreak will be breakthrough infections (i.e. infections in individuals with a history of vaccination) [11,12]. Transmission of infection from individuals with breakthrough infections seems to be rare [10,13-15], and the recently published national measles guidelines by Public Health England recommend only limited contact tracing around such cases [16].…”

Section: Introductionmentioning

confidence: 99%

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Measles outbreak in Gothenburg urban area, Sweden, 2017 to 2018: low viral load in breakthrough infections

et al. 2019

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In an outbreak of measles in Gothenburg, Sweden, breakthrough infections (i.e. infections in individuals with a history of vaccination) were common. The objective of this study was to compare measles RNA levels between naïve (i.e. primary) and breakthrough infections. We also propose a fast provisional classification of breakthrough infections. Medical records were reviewed and real-time PCR-positive samples genotyped. Cases were classified as naïve, breakthrough or vaccine infections. We compared clinical symptoms and measles RNA cycle threshold (Ct) values between breakthrough and naïve infections. Sixteen of 28 confirmed cases of measles in this outbreak were breakthrough infections. A fast provisional classification, based on previous history of measles vaccination and detectable levels of measles IgG in acute serum, correctly identified 14 of the 16 breakthrough infections, confirmed by IgG avidity testing. Measles viral load was significantly lower in nasopharyngeal samples from individuals with breakthrough compared with naïve infections (median Ct-values: 32 and 19, respectively, p < 0.0001). No onward transmission from breakthrough infections was identified. Our results indicate that a high risk of onward transmission is limited to naïve infections. We propose a fast provisional classification of breakthrough measles that can guide contact tracing in outbreak settings.

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Section: Discussionsupporting

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Measles outbreak in Gothenburg urban area, Sweden, 2017 to 2018: low viral load in breakthrough infections

et al. 2019

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“…This finding is consistent with those in other countries, such as Italy, Japan and Portugal. In Italy, Japan and Portugal, the majority of cases occurred among unvaccinated adolescents and young adults [15–17]. These findings indicate that measles elimination presents a major challenge because < 8 months are too young to be vaccinated and adolescent/young adults are not targeted for routine immunization.…”

Section: Discussionmentioning

confidence: 99%

“…In this study, 150 non-H1 viruses representing six genotypes were detected among the extensive background of viruses of the predominant H1 genotype, indicating a very high sensitivity of measles surveillance in China. In countries including Japan, the Republic of Korea, the USA, Canada and Ireland, where endemic transmission of the virus has been interrupted, imported viruses were introduced to the countries with limited transmission [17, 32–36].…”

Section: Discussionmentioning

confidence: 99%

Molecular characterization of measles viruses in China: Circulation dynamics of the endemic H1 genotype from 2011 to 2017

et al. 2019

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Due to the Expanded Program on Immunization (EPI) and supplementary immunization activities (SIAs) in China, the incidence of measles in China has decreased extensively. The incidence reached its lowest levels in contemporary history in 2012 and 2017, with incidence rates of 4.6 and 4.3 per million population, respectively. However, more than 147,000 measles cases were reported from 2013 to 2016. Furthermore, the proportions of cases in infants < 8 months and adults have been increasing since 2013, representing a considerable challenge for measles elimination in China. A total of 14,868 measles viruses were isolated from confirmed measles cases from 2011 to 2017, of which 14,631 were identified as the predominant endemic genotype, H1; 87 were identified as genotype A viruses that were vaccine associated strains; and 150 were identified as non-H1 genotype viruses. The non-H1 genotype viruses included 62 D8 viruses, 70 D9 viruses, 3 D11 viruses, 14 B3 viruses, and 1 G3 virus, which were identified as imported or import-related viruses that caused sporadic cases or small outbreaks. Most of the transmission chains detected during the period 2011–2012 were interrupted and were followed by many new transmission chains of unknown origin that spread, causing a large measles resurgence in China during 2013–2016. After 4 years of measles resurgence and continuous implementation of the routine immunization program and SIAs, the population immunity reached a sufficiently high level to interrupt most of the transmission chains; only a few strains survived, which continued to be sporadically detected in China in 2017. In the present study, the results from the combined epidemiological and molecular virological data demonstrated the great progress towards measles elimination in China by the further analysis of circulation dynamics for the endemic H1 genotype measles virus from 2011 to 2017. And this study accumulated critical baseline data on circulating wild-type measles viruses in China and provides comprehensive information to the world. These comprehensive baseline data provide evidence to support measles elimination in the future, not only in China but also in other countries worldwide. In addition, the information will be very useful to other countries for tracing their sources of measles cases and for identifying transmission links, which can help prevent potential measles outbreaks.

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“…Este brote, con transmisión laboral/familiar, destaca por la clínica atípica en dos de los casos, sospechados gracias a la difusión del caso 1 a través de Venres Epidemiolóxico . Los casos de sarampión atípico suelen relacionarse con el antecedente de vacunación 4 , 5 , 6 . En los brotes de sarampión de Portugal 6 , el 44,6% de los casos no cumplían definición de caso y un número elevado eran trabajadores sanitarios vacunados.…”

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¿Necesidad de cambio en la definición de caso del sarampión?

Losada-Castillo¹,

Abraira-García²,

Purriños-Hermida³

et al. 2020

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Challenging measles case definition: three measles outbreaks in three Health Regions of Portugal, February to April 2018

Cited by 12 publications

References 10 publications

Measles outbreak in Gothenburg urban area, Sweden, 2017 to 2018: low viral load in breakthrough infections

Measles outbreak in Gothenburg urban area, Sweden, 2017 to 2018: low viral load in breakthrough infections

Molecular characterization of measles viruses in China: Circulation dynamics of the endemic H1 genotype from 2011 to 2017

¿Necesidad de cambio en la definición de caso del sarampión?

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