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Objective To analyze the epidemiological characteristics of measles cases with immunization history of measles-containing vaccine (MCV), and to provide a basis for improving measles prevention and control measures. Methods Data were collected through the measles surveillance system and the immunization program information management system. Data were analyzed by descriptive epidemiological methods. Results A total of 9 164 cases of measles were reported in Liaoning Province during 2014-2021, of which the cases of measles with immunization history of 1 dose MCV accounted for 5.64%, and ≥ 2 doses accounted for 3.60%. There was a statistically significant difference in the immunization proportion among different years (χ2=184.534, P2=109.448, P2=4.147, P<0.05). The onset time of most cases was over 2 weeks after the last dose of MCV vaccination, accounting for 82.06%. The incidence rates of fever, cough, catarrh symptoms, conjunctivitis, lymph node enlargement and articular pain were all significantly lower in the cases with immunization history than those in the patients without a history of MCV immunization (P<0.05). Conclusion The cases with immunization history account for a certain proportion in measles cases, mainly secondary vaccination failure. The incidence rate of fever, cough, catarrhal symptoms, conjunctivitis, Koch's patches, lymphadenopathy, joint pain, and other clinical symptoms in measles patients with a history of MCV immunization is lower than that in patients without immunization history. Inoculation of MCV is of great significance in relieving clinical symptoms. It is necessary to inoculate two doses of MCV in time for measles prevention and control.
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Objective@#To analyze the genetic characterization of 2B genotype rubella virus strains first isolated in Liaoning province.@*Methods@#Vero/Slam cells were used to isolate rubella viruses from throat swabs. Fragments of the E1 gene (739 nucleotides) were amplified by reverse transcription-polymerase chain reaction (RT-PCR) and the PCR products were sequenced and analyzed. The phylogenetic trees were constructed with rubella 2B genotypes reference strains.@*Results@#RVi/Liaoning.CHN/13.18/1[2B] was isolateded from the case which had a history of international travel and probably imported from abroad. RVi/Liaoning.CHN/13.18/1[2B] was in the same 1ineage with RVs/Edinburgh.GBR/6.12[2B] and RVs/Kawasaki.JPN/17.11/1[2B], but far from the epidemic strains isolated in China in recent years. RVi/Liaoning.CHN/14.18/1[2B] belonged to the same lineage with rubella virus 2B genotype strains isolated in China from 2014 to 2015, and had the highest homology with RVi/Chouzhou.Anhui.CHN/17.15/2[2B] and RVi/Shaoyang.Zhejiang. CHN/13.13[2B].@*Conclusions@#It was the first time to isolate the 2B genotype rubella virus in Liaoning province and the strain belonged to different 1ineage.
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Objective@#To analyze the gene characterization on the first imported D8 genotype measles virus in Liaoning province.@*Methods@#In this study, Vero/Slam cells were used to isolate measles viruses from throat swabs. Fragments of the H gene (1854 nucleotides) and N gene (450 nucleotides) were amplified by reverse transcription-polymerase chain reaction (RT-PCR) and the PCR products were sequenced and analyzed.@*Results@#The measles virus isolates and World Health Organization (WHO) D8 genotype reference strain (MVi/Manchester.GBR/30.94) belonged to the same branch in the genetic relationship tree. The nucleotide homology of the N and H gene was 98.9%. Phylogenetic trees were constructed with reference strains of the genotype D8 measles virus of China downloaded from GenBank. The result showed that the nucleotide similarities between the measles virus isolated in this study and the D8 genotype measles virus prevalent in Hong Kong from 2012 to 2016 and MVi/LosPatios.COL/11.18/D8 in Columbia was 100%.@*Conclusions@#It is the first time to do surveillance for the D8 genotype measles virus since measles virus surveillance was carried out. It was of great significance to accumulate the bases of measles virus molecular epidemiology in Liaoning province, and helpful to analyze and trace the transmission of measles virus in the whole country and the world.