Measles and rubella laboratory network - overview
With the measles elimination and rubella control goal in the Region, the WHO measles and rubella laboratory network has played a critical role in monitoring the progress of measles elimination and rubella control by confirming measles and rubella cases, as well as establishing genotyping and providing molecular epidemiological data for decision-makers in national immunization programmes. Timeliness in providing such reliable laboratory data would be critical to identify and respond to imported or endemic measles transmission, particularly as the Region approaches measles elimination
The WHO measles and rubella laboratory network in the Western Pacific Region consists of one global specialized laboratory (GSL) in Japan, three regional reference laboratories (RRLs) in Australia, China and Hong Kong (China), 16 national laboratories (NLs), 31 provincial laboratories and 331 prefecture laboratories in China and two subnational laboratories in Vietnam and one subnational laboratory in Malaysia. With addition of three subnational laboratories in Vietnam and Malaysia in 2011, the total number of measles and rubella network laboratories has grown to 385 in the region
To ensure the quality of network laboratories, WHO conducts an accreditation of 51 network laboratories including 31 provincial laboratories in China. As of Sep 2012, all network laboratories except one national laboratory have been accredited. Among 31 provincial laboratories in China, all laboratories except one provincial laboratory have been accredited. Accreditation of 331 prefectural laboratories in China is conducted by provincial laboratories in collaboration with China CDC.
Out of 385 laboratories in the Region, 52 laboratories including 31 provincial laboratories in China participate in the WHO global measles and rubella proficiency programme coordinated by the Victorian Infectious Diseases Reference Laboratory (VIDRL), Australia. As a quality assurance measure, a confirmatory testing mechanism has been established and most network laboratories in the Region have sent a proportion of serum samples to RRLs or GSL.
Among the four WHO-designated laboratories in the Pacific, namely, Fiji, French Polynesia, New Caledonia and Guam, the laboratory in Fiji participates in the WHO accreditation programme with an on-site review, while laboratories in French Polynesia and Guam participate without an on-site review.
Detection of measles or rubella IgM in serum is the standard test for the rapid diagnosis of measles and rubella. There are several commercial IgM ELISA kits available, but the WHO global measles and rubella laboratory network recommends Siemens measles and rubella IgM ELISA kits.
As the role of the measles and rubella laboratory network also extends to molecular surveillance, laboratories with virus isolation, molecular diagnosis and sequencing capabilities are encouraged to perform virus isolation, sequencing and genotyping. Genotype and sequencing information are submitted to the WHO genotype and MeaNS database by national or regional reference laboratories. Genotype data on recent measles virus strains are available from most countries except Pacific island countries.
The Hong Kong (China) measles and rubella laboratory was designated as a WHO regional reference laboratory (RRL) in 2007 to provide additional regional support for confirming samples from national laboratories and for genotyping measles and rubella viruses circulating in the Region. In 2009-2010, the Hong Kong (China) RRL assisted in identifying genotypes of measles viruses circulating in Cambodia, the Lao People's Democratic Republic, Macao (China), Malaysia, Mongolia, the Philippines and Viet Nam, using confirmatory serum or virus isolation samples.
In 2011, more than 21,134 samples were received in network laboratories except China and 6017 samples were positive for measles IgM and 5336 samples were positive for rubella IgM. China has established an extensive national network of 362 subnational laboratories consisting of 31 provincial and 331 prefectural laboratories with a strong quality assurance programme of confirmatory testing and proficiency tests. China laboratory network processed 32677 samples from 30472 cases for measles IgM in 2011 and 8892 were positive for measles IgM. Among 27955 samples tested for rubella IgM detection, 4954 samples were positive for rubella.
Network laboratories are invited to regional meetings to discuss progress and challenges of the network as well as to hands-on training workshops to improve laboratory capacities for measles and rubella virus isolation and identification. In February 2010 and September 2011, network laboratories participated in the 2nd and 3rd Meetings on Vaccine Preventable Diseases Laboratory Networks in the Western Pacific Region. (Please find below the link to the related meeting report)
Following two regional hands on training workshops on the molecular diagnosis of Measles and Rubella in 2009 and 2010, the region's capacity to detect circulating genotypes has improved dramatically and endemic transmission of H1 and D9 measles strains is still ongoing in some countries in the region. Genotype information on circulating measles and rubella virus strains is available in most countries in the region except Pacific Island Countries. The labnet will continue to monitor the circulating genotypes of measles and rubella viruses to provide the evidence to prove measles elimination and rubella control in the region. (Please find below the link to the Measles-Rubella Bulletin)
To improve country reporting of measles laboratory data to the WHO Regional Office, a new case-based reporting format was developed and has been in use since January 2008. As of September 2012, 15 out of 17 laboratories have been sending laboratory data to the WHO Regional Office on a monthly basis. Laboratory data including measles genotypes identified from each country have been included in the WHO Measles-Rubella Bulletin from 2011. (Please find below the link to the Measles-Rubella Bulletin)