Topazian Hillary M, Gumbo Austin, Brandt Katerina, Kayange Michael, Smith Jennifer S, Edwards Jessie K, Goel Varun, Mvalo Tisungane, Emch Michael, Pettifor Audrey E, Juliano Jonathan J, Hoffman Irving
Department of Epidemiology, University of North Carolina at Chapel Hill Gillings School of Global Public Health, Chapel Hill, North Carolina, USA
National Malaria Control Programme, Malawi Ministry of Health, Lilongwe, Malawi.
BMJ Glob Health. 2021 May;6(5). doi: 10.1136/bmjgh-2021-005447.
Malawi's malaria burden is primarily assessed via cross-sectional national household surveys. However, malaria is spatially and temporally heterogenous and no analyses have been performed at a subdistrict level throughout the course of a year. The WHO recommends mass distribution of long-lasting insecticide-treated bed nets (LLINs) every 3 years, but a national longitudinal evaluation has never been conducted in Malawi to determine LLIN effectiveness lifespans.
Using District Health Information Software 2 (DHIS2) health facility data, available from January 2018 to June 2020, we assessed malaria risk before and after a mass distribution campaign, stratifying by age group and comparing risk differences (RDs) by LLIN type or annual application of indoor residual spraying (IRS).
711 health facilities contributed 20 962 facility reports over 30 months. After national distribution of 10.7 million LLINs and IRS in limited settings, malaria risk decreased from 25.6 to 16.7 cases per 100 people from 2018 to 2019 high transmission seasons, and rebounded to 23.2 in 2020, resulting in significant RDs of -8.9 in 2019 and -2.4 in 2020 as compared with 2018. Piperonyl butoxide (PBO)-treated LLINs were more effective than pyrethroid-treated LLINs, with adjusted RDs of -2.3 (95% CI -2.7 to -1.9) and -1.5 (95% CI -2.0 to -1.0) comparing 2019 and 2020 high transmission seasons to 2018. Use of IRS sustained protection with adjusted RDs of -1.4 (95% CI -2.0 to -0.9) and -2.8% (95% CI -3.5 to -2.2) relative to pyrethroid-treated LLINs. Overall, 12 of 28 districts (42.9%) experienced increases in malaria risk in from 2018 to 2020.
LLINs in Malawi have a limited effectiveness lifespan and IRS and PBO-treated LLINs perform better than pyrethroid-treated LLINs, perhaps due to net repurposing and insecticide-resistance. DHIS2 provides a compelling framework in which to examine localised malaria trends and evaluate ongoing interventions.
马拉维的疟疾负担主要通过全国性的横断面家庭调查来评估。然而，疟疾在空间和时间上具有异质性，且尚未在一个分区层面上进行过全年的分析。世界卫生组织建议每3年大规模分发长效驱虫蚊帐（LLINs），但马拉维从未进行过全国性的纵向评估以确定LLINs的有效使用寿命。
利用2018年1月至2020年6月期间可获取的地区卫生信息软件2（DHIS2）卫生设施数据，我们评估了一次大规模分发活动前后的疟疾风险，按年龄组进行分层，并比较不同类型LLINs或室内滞留喷洒（IRS）年度应用情况下的风险差异（RDs）。
711个卫生设施在30个月内提供了20962份设施报告。在全国分发了1070万顶LLINs并在有限地区开展IRS后，2018年至2019年疟疾高发季节的疟疾风险从每100人25.6例降至16.7例，2020年又反弹至23.2例，与2018年相比，2019年和2020年的显著RDs分别为-8.9和-2.4。与拟除虫菊酯处理的LLINs相比，胡椒基丁醚（PBO）处理的LLINs更有效，将其2019年和2020年疟疾高发季节与2018年进行比较时，调整后的RDs分别为-2.3（95%置信区间-2.7至-1.9）和-1.5（95%置信区间-2.0至-1.0）。IRS的使用持续提供了保护，相对于拟除虫菊酯处理的LLINs，调整后的RDs分别为-1.4（95%置信区间-2.0至-0.9）和-2.8%（95%置信区间-3.5至-2.2）。总体而言，28个地区中有12个（42.9%）在2018年至202期间疟疾风险有所增加。
马拉维的LLINs有效使用寿命有限，IRS和PBO处理的LLINs比拟除虫菊酯处理的LLINs表现更好，这可能是由于蚊帐重新利用和抗药性所致。DHIS2提供了一个有说服力的框架，可用于研究局部疟疾趋势并评估正在进行的干预措施。
