Measles incidence rate and a phylogenetic study of contemporary genotype H1 measles strains in China: is an improved measles vaccine needed?

Abstract

The incidence of measles in China has increased over the last decade. To evaluate the genetic variation of measles strains, 16 measles wild-type virus strains were isolated from 14 vaccinated cases and 2 nonvaccinated cases in Jilin Province during 2005-2006, and their nucleoprotein (N) and hemagglutinin (H) genes were amplified by RT-PCR. The amplified products were sequenced and compared with the Edmonston virus and the existing vaccine strains (Changchun-47 and Shanghai-191). The results showed that the variation rate between the vaccine and wild-type strains was 9.8-12.0% in the N gene and 5.9-6.9% in the H gene, respectively. In addition, cross-neutralization assays revealed that although sera obtained from infants following primary vaccination effectively neutralized vaccine strains, the capacity in neutralizing H1 wild-type measles virus isolates was decreased fourfold. Antigenic ratios testing revealed that the antigenic relatedness between wild-type measles viruses and existing vaccine strains was notably low. These data suggest that the increased incidence of measles in Jilin Province may be attributed to the antigenic drift between wild-type and vaccine strains. Our findings strengthen the recommendation of supplemental immunization with existing vaccines and also strongly suggest a need for developing new vaccines to better control measles virus outbreaks.

Functional and Structural Characterization of Neutralizing Epitopes of Measles Virus Hemagglutinin Protein

“…Consequently, based on these observations, there is no evidence to suggest that MV undergoes a major antigenic drift. Nevertheless, several studies have suggested that currently circulating MV strains show antigenic variations, which could potentially affect the efficacy of vaccination (4,(13)(14)(15)(16)(17). Many amino acid residues have been documented to constitute a portion of an epitope.…”

Molecular Characterization of Wild Type Measles Virus from Adult Patients in Northern China, 2014

“…Interestingly, analysis of antigenic relatedness of wild type strains to vaccine strains during a 2005-2006 outbreak in Jilin Province suggested that the increased incidence of measles could be due to antigenic drift between wild type and vaccine strains. 4 Studies showing that neutralizing titers of serum samples from vaccinated individuals were lower against some wild type viruses compared to vaccine strains and that monoclonal antibodies against the H protein can detect antigenic differences 4,28 suggested that vaccine efficacy can be evaluated by monitoring antigenic variations.…”

“…Indeed, MeVs which were variants in the N and H genes were isolated during the outbreak in Jilin Province during [2005][2006], where the postvaccination sera had diminished neutralizing titers against wildtype strains. 4 Molecular epidemiological studies of MeVs have therefore emerged as an important means of establishing links, tracing transmission pathways, allowing detection of imported cases, and classification of suspected cases as caused by vaccine or wild type strains. 5 Virologic surveillance has shown that genotype H1 MeV has been the predominant strain circulating in China since 1993, and is endemic throughout China.…”

“…Outbreaks have been attributed to a number of reasons including 1) failure of the primary vaccine, 2) an unvaccinated population living in remote regions and 3) human migration. 4 Failure of vaccination can also be due to factors such as age of first vaccination, the number of doses administered to children (1 or 2 doses) and a cold chain of vaccine.…”

Antigenic Drift Defines a New D4 Subgenotype of Measles Virus

“…All 194 WHO member states have committed to reducing measles deaths, and the Global Measles and Rubella Strategic Plan set the goal of measles elimination by 2020 through increased vaccination coverage (7). In this regard, measles cases among vaccinated people have raised concerns about waning immunity in vaccinees and the occurrence of antigenic changes in currently circulating strains, raising concerns as to whether MeV elimination can be achieved (8)(9)(10)(11)(12).…”