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Measles In Guangdong, China: Surveillance and Vaccination From 2005 to 2021
37 Pages Posted: 6 Jan 2023
More...Abstract
Background: Although the National Measles Elimination Action Plan (NMEAP, 2006-2012) promoted a progress goal of measles elimination in China, the resurgence of measles in variety areas of China after NMEAP indicated a complexity between measles transmission and vaccination, and a regional in depth analysis was needed to assess it in population level which may guide for measles elimination in other west pacific countries.
Methods: Measles surveillance and vaccination data during 2005-2021 in Guangdong, China was obtained from NNIDRIS and MSIIP system. We used interrupted event sequence (ITS model) and interrupted linear regression to quantitatively evaluate the intervention effect and persistence of immune strategy adjustment at different time nodes on the incidence. The effects of vaccination were assessed by using a kinetic model.
Findings: Since the adjustment of measles vaccination strategy in Guangdong Province in September 2008, we observed the monthly and weekly reported incidence of measles decreased by 1.12/100000 and 0.05/100000 (P=0.004 and P=0.199) compared with that before vaccination, and the long-term effects decreased by 0.03/100000 and 0.002/100000 (P=0.141 and P=0.287) on average monthly and weekly. After MMR vaccination in June 2020, the monthly and weekly reported incidence of measles decreased by 0.002/100000 and 0.001/100000 (P=0.728 and P=0.334) compared with that before vaccination, but the long-term effects increased by 0.0006/100000 and 0.0002/100000 (P=0.456 and P=0.556) on average monthly and weekly. There was correlation between measles annual incidence rate with lagging 3 years, and vaccination rate was the strongest factor with it. In addition, the protection rate of two doses of vaccine (range 99.62%-99.98%) is greater than that of one dose (range 94.61%-99.95%). For children under two years of age, if the vaccination rate drops to 99% since Jan 2017 (2016), the small (large) epidemic would begin from 2018, and the number of cases reported will increase 1.68 times, 5.01 times, 15.60 times and 22.23 times (10.29 times, 32.12 times, 108.24 times and 166.35 times) respectively in each following year.
Interpretation: We provide real-world evidence that the effect of combined immunization strategy of MV and MR may be better than that of single inoculation of MV. The short-term effect of MMR vaccination is better than other vaccines, but its long-term effect is still unclear. Two doses vaccine and high coverage is the key to reduce measles incidence. These findings will benefit policy-making of measles vaccination and prevention.
Funding: This work was supported by grants The National Key Research and Development Program of China (2020YFC1200100), the Guangzhou Science and Technology Program (201904010012), the National Natural Science Foundation of China (12171116), and the Guangdong Science and Technology Program (2021B1212030007).
Declaration of Interests: All the authors declare that they have no conflicts of interest.
Keywords: measles；epidemiological characteristic；vaccine effectiveness；Influencing factor
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