ABSTRACT
Objective To analyze the epidemic characteristics of varicella and the genetic characteristics of varicella zoster virus (VZV) in Yangzhou in 2021, and to provide a theoretical basis for the scientific prevention and control of varicella in Yangzhou. Methods Descriptive epidemiological analysis was carried out on the varicella outbreaks reported in Yangzhou in 2021. Throat swabs or herpes fluid samples from varicella cases in 2021 were collected, and the viral nucleic acid was detected by real-time fluorescent quantitative PCR. The genotype and evolutionary relationship of the virus strain were determined according to the 6 SNPs in the ORF22 gene fragment sequence. Results In 2021, there were 20 varicella outbreaks in Yangzhou, involving 147 cases, all of which occurred in kindergartens and primary and secondary schools, and the peak incidence was in the age group of 4-7 years old. The high incidence time of the outbreaks was from May to July, and from November to January of the next year. The varicella vaccination rate of the cases was low, and all were 1-dose vaccination. The gene sequencing results of 8 samples were J/clade 2, and 3 of them had A-C synonymous mutation at position 37997 in ORF22 sequence. Conclusion In 2021, varicella outbreaks in Yangzhou occurred mainly in kindergartens and schools. Preschool children are susceptible, all of which are caused by J/clade 2 varicella-zoster virus. It is suggested to strengthen the monitoring and management of the varicella epidemic situation in schools in the city, and at the same time incorporate the varicella vaccine into the routine immunization program of the city and strengthen 2 doses of varicella vaccination.
ABSTRACT
Objective To evaluate the effectiveness and benefit of influenza vaccination among school-age children in Xining, Qinghai. Methods A total of 215 children were randomly recruited as the vaccination group and vaccinated with trivalent split influenza vaccine. At the same time, 215 healthy children (no known diseases and past history reported, and no vaccinations) who underwent physical examinations during the same period were selected as the control group. The basic demographic information was investigated and a 1-year follow-up was carried out. Results The demographic characteristics of children in the vaccinated group and the control group were not significantly different (P>0.05), and were comparable between the two groups. After four follow-up visits within one year for the enrolled children, the overall incidence of influenza-like illness in children in the vaccinated group and the control group was 7.4% (16/215) and 16.7% (36/215), respectively, and the difference was statistically significant (χ2=8.75, P2=5.03, P2=1.37, P>0.05). The protection rate was 52.6%, and the protection index was 2.11. The proportions of irrational use of antibiotics were 6.0% (13/215) and 20.9% (45/215), respectively, and the difference was statistically significant (χ2=20.41, P<0.05). The protection rate was 71.3%, and the protection index was 3.48. The per capita income from vaccination was 667.9 yuan, and the benefit-cost ratio was 9.97:1. Conclusion Influenza vaccination for school-age children can effectively prevent the incidence of influenza-like diseases and the common cold, and the vaccination is cost-effective.