Objective: To examine the impact of COVID-19 pandemic on the epidemic status of imported malaria and national malaria control program in China, so as to provide insights into post-elimination malaria surveillance.
Methods: All data pertaining to imported malaria cases were collected from Anhui Province, Hubei Province, Henan Province, Zhejiang Province and Guangxi Zhuang Autonomous Region during the period from January 1, 2018 through December 31, 2021. The number of malaria cases, species of malaria parasites, country where malaria parasite were infected, diagnosis and treatment after returning to China, and response were compared before (from January 1, 2018 to January 22, 2020) and after the COVID-19 pandemic (from January 23, 2020 to December 31, 2021).
Results: A total of 2 054 imported malaria cases were reported in Anhui Province, Hubei Province, Henan Province, Zhejiang Province and Guangxi Zhuang Autonomous Region during the period from January 1, 2018 to December 31, 2021, and there were 1 722 cases and 332 cases reported before and after the COVID-19 pandemic, respectively. All cases were reported within one day after definitive diagnosis. The annual mean number of reported malaria cases reduced by 79.30% in Anhui Province, Hubei Province, Henan Province, Zhejiang Province and Guangxi Zhuang Autonomous Region after the COVID-19 pandemic (171 cases) than before the pandemic (826 cases), and the number of monthly reported malaria cases significantly reduced in Anhui Province, Hubei Province, Henan Province, Zhejiang Province and Guangxi Zhuang Autonomous Region since February 2020. There was a significant difference in the constituent ratio of species of malaria parasites among the imported malaria cases in Anhui Province, Hubei Province, Henan Province, Zhejiang Province and Guangxi Zhuang Autonomous Region before and after the COVID-19 pandemic (χ2 = 146.70, P < 0.05), and P. falciparum malaria was predominant before the COVID-19 pandemic (72.30%), while P. ovale malaria (44.28%) was predominant after the COVID-19 pandemic, followed by P. falciparum malaria (37.65%). There was a significant difference in the constituent ratio of country where malaria parasites were infected among imported malaria cases in Anhui Province, Hubei Province, Henan Province, Zhejiang Province and Guangxi Zhuang Autonomous Region before and after the COVID-19 pandemic (χ2 = 13.83, P < 0.05), and the proportion of malaria cases that acquired Plasmodium infections in western Africa reduced after the COVID-19 pandemic that before the pandemic (44.13% vs. 37.95%; χ2 = 4.34, P < 0.05), while the proportion of malaria cases that acquired Plasmodium infections in eastern Africa increased after the COVID-19 pandemic that before the pandemic (9.58% vs. 15.36%; χ2 = 9.88, P = 0.02). The proportion of completing case investigation within 3 days was significantly lower after the COVID-19 pandemic than before the pandemic (96.69% vs. 98.32%; χ2= 3.87, P < 0.05), while the proportion of finishing foci investigation and response within 7 days was significantly higher after the COVID-19 pandemic than before the pandemic (100.00% vs. 98.43%; χ2 = 3.95, P < 0.05).
Conclusions: The number of imported malaria cases remarkably reduced in Anhui Province, Hubei Province, Henan Province, Zhejiang Province and Guangxi Zhuang Autonomous Region of China during the COVID-19 pandemic, with a decreased proportion of completing case investigations within 3 days. The sensitivity of the malaria surveillance-response system requires to be improved to prevent the risk of secondary transmission of malaria due to the sharp increase in the number of imported malaria cases following the change of the COVID-19 containment policy.
［摘要］ 目的 分析新型冠状病毒感染 (COVID-19) 疫情对我国输入性疟疾疫情及疟疾防控工作的影响, 为消除疟疾后 监测工作提供参考。方法 收集2018年1月1日—2021年12月31日安徽省、湖北省、河南省、浙江省和广西壮族自治区 报告的输入性疟疾病例资料, 比较COVID-19疫情前 (2018年1月1日—2020年1月22日)、后 (2020年1月23日—2021年 12月31日) 上述5省疟疾病例数、感染虫种、感染来源地、回国后诊疗和处置情况。结果 2018年1月1日—2021年12 月31日, 5个省份累计报告输入性疟疾病例2 054例, COVID-19疫情前、后分别报告1 722例和332例, 均为输入性病例, 所有病例均在确诊后1 d内报告。COVID-19疫情后, 5个省份平均每年报告疟疾病例数 (171例) 较疫情前 (826例) 下降 79.30%; 自2020年2月起, 5个省份每月报告疟疾病例数明显减少。COVID-19疫情前后5个省份疟疾病例感染虫种构成 比差异有统计学意义 (χ2 = 146.70, P < 0.05); COVID-19疫情前以恶性疟病例为主 (72.30%); COVID-19疫情后, 恶性疟病 例占比下降至37.65%, 卵形疟病例占比上升至最高 (44.28%)。COVID-19疫情前后, 5个省份疟疾病例感染来源地构成 比差异有统计学意义 (χ2 = 13.83, P < 0.05); 与COVID-19 疫情前相比, 疫情后来自西非的病例占比降低 (44.13% vs. 37.95%; χ2 = 4.34, P = 0.037), 来自东非的病例占比升高 (9.58% vs.15.36%; χ2 = 9.88, P = 0.02)。COVID-19疫情后病例3 d 内流行病学调查完成率 (96.69%) 低于疫情前 (98.32%) (χ2 = 3.87, P < 0.05), 7 d内疫点调查处置完成率 (100.00%) 高于 疫情前 (98.43%) (χ2 = 3.95, P < 0.05)。结论 COVID-19疫情期间, 我国安徽省、湖北省、河南省、浙江省和广西壮族自 治区输入性疟疾疫情大幅下降, 3 d内病例流行病学调查完成率下降。提示需增强监测系统敏感性, 以防范COVID-19疫 情防控政策改变后输入性疟疾病例激增带来的继发传播风险。.
Keywords: Anhui Province; COVID - 19; Guangxi Zhuang Autonomous Region; Henan Province; Hubei Province; Imported case; Malaria; Zhejiang Province.