Measles Outbreak in Venezuela: A New Challenge to Postelimination Surveillance and Control?

Abstract

The circulation of wild measles virus was interrupted in Venezuela in February 2007 after the catch-up vaccination (1994) and monitoring (1998) and in response to the measles outbreak in 2001. Traditionally, the routine coverage with measles-mumps-rubella vaccine does not exceed 85%. In February 2006, a measles outbreak started by importation in the State Miranda; this extended to 7 states and lasted 50 weeks with an intermediate period of 17 weeks without reported cases. New cases were reported in the States Guarico and Amazon. The pattern of circulation of the silent period was determined through the use of retrospective search for measles; this showed that 57% of suspected cases did not enter the surveillance system. Molecular epidemiology made it possible to identify B3 as only genotype, which also circulated in Spain. The epidemiological and clinical characteristics of measles have been modified; these determine outbreaks identified late, of slow expansion, silent, and with limited case-fatality, compared with classical outbreaks. The outbreak spread by that behavior was not recognized and the classical control measures did not result. The beginning of a broader and intense vaccination was delayed, partly by weaknesses in the sensitivity of the system. It is crucial to recognize the new behavior of measles and the effectiveness of the classical control measures, and especially to establish criteria for interruption of the circulation to control an outbreak in this stage of elimination.

Resurgence of Vaccine-Preventable Diseases in Venezuela as a Regional Public Health Threat in the Americas

“…In Venezuela, circulation of wild measles was interrupted in February 2007 after a mass vaccination campaign that followed outbreaks in 2001 and 2006 ( 15 ). However, since 2017, measles has reemerged in Venezuela, particularly within vulnerable indigenous populations, and has subsequently reached neighboring countries (Figure 1, panel A) ( 16 ).…”

Analysis and Factors Associated with Measles in Larut, Matang and Selama Districts, Perak, Malaysia

“…A study evaluating the measles clinical case definition in New York City reported the negative predictive value of the case definition at 98% ( 36 ). Similarly, Sarmiento et al ( 37 ) reported a negative predictive value of 86% of the clinical case definitions in their study in Venezuela. Furthermore, a review of four studies reported that the sensitivity of the clinical case definition was high (76%–88%).…”

Monitoring progress toward measles elimination by genetic diversity analysis of measles viruses in China 2009–2010

“…These data indicate that the epidemiology of measles is changing from widespread prevalence to more limited, focal outbreaks. The experience from WHO Region of the Americas showed that, as the region progressed towards elimination, measles epidemics were usually concentrated in areas with poor implementation of the vaccination strategy, such as the measles outbreak that occurred in Sao Paulo in Brazil in 1997, and the measles outbreak in Venezuela . It is important to note that nosocomial infections are now important risk factors for measles epidemics in China .…”