Weekly IDSR Bulletin
Epidemiological Week 21 (18-24 May, 2026)
Editorial Team
I. Performance & Surveillance
Reporting Completeness & Timeliness Analysis
The national reporting performance for Epidemiological Week 21 has achieved a highly positive trajectory, registering 95.6% for reporting completeness and an outstanding 95.1% for reporting timeliness on the One Health Surveillance Platform (OHSP). This performance demonstrates the robust capacity of our integrated tracking systems to capture facility data with minimal informational latency. Out of the 33 designated national reporting sites, all health zones successfully met the minimum target of 80% for both completeness and timeliness. This widespread platform adoption provides public health decision-makers with real-time situational awareness across the territory.
When evaluated against the previous historical baseline in Epidemiological Week 20, which achieved 95.0% completeness and 94.0% timeliness, Week 21 displays a general improvement across both surveillance domains. Completeness rose by 0.6 percentage points, while timeliness climbed by 1.1 percentage points. This positive trend was primarily anchored by Central Hospitals (100.0% on both metrics) and the Central West and South West Zones. However, administrative delays persist at the district level: Balaka DHO (72.0% completeness and timeliness) and Karonga DHO (61.0% completeness and 57.0% timeliness) both failed to meet the critical 80% threshold, presenting minor tracking blind spots.
To address these remaining gaps and maintain optimal surveillance parameters, the National IDSR Secretariat recommends immediate administrative follow-up. Balaka, Karonga, Dowa, and Zomba DHOs must prioritize targeted administrative interventions to resolve database entry delays. IDSR coordinators and Zonal Epidemiology Officers must ensure timely verification and validation of clinical data immediately after facility focal points submit weekly forms to safeguard platform responsiveness during active outbreaks.
II. Disease Morbidity
Malaria Morbidity & Mortality
Malaria remains the dominant priority clinical condition under active surveillance in Malawi, with Epidemiological Week 21 recording an immense burden of 37,499 cases (37,059 OPD and 440 IPD) alongside 4 associated inpatient deaths. This heavy volume of clinical cases indicates intense transmission dynamics, placing constant pressure on primary care facilities, diagnostic laboratories, and essential antimalarial drug inventories. High-burden districts like Blantyre (4,069 cases), Mangochi (3,155 cases), and Chikwawa (3,023 cases) continue to represent key transmission hotspots requiring sustained public health intervention.
When contrasted with the previous baseline in Epidemiological Week 20, the malaria data reveals an upward trajectory in morbidity but a positive decline in inpatient mortality. Total malaria cases rose by 8.3%, surging from 34,625 cases in Week 20 to 37,499 cases in Week 21. Conversely, confirmed inpatient deaths decreased by 50.0%, falling from 8 down to 4. This synchronous drop in fatal outcomes suggests improving clinical therapeutic timing and supportive inpatient protocols, even as environmental factors support vector propagation across high-burden districts.
To address this rising transmission trend, the National Malaria Control Program must coordinate immediate antimalarial supply chain audits to ensure uninterrupted buffer stocks of Artemisinin-based Combination Therapy (ACTs) and Rapid Diagnostic Tests (RDTs). Clinical teams must conduct rigorous mortality audits on the 4 recorded deaths to identify systemic or clinical delays in administering intravenous artesunate. Concurrently, Health Surveillance Assistants (HSAs) must scale up risk communication campaigns to emphasize immediate care-seeking behaviors for all febrile illnesses.
Enteric Diseases (Typhoid & Diarrhoea)
The surveillance of waterborne enteric pathogens in Epidemiological Week 21 has flagged a significant clinical concern, with Typhoid fever cases recorded at 113 (99 OPD and 14 IPD) and Bloody Diarrhoea cases totaling 788. Waterborne disease transmission remains a persistent threat, especially in urban areas with compromised water and sanitation networks. A notable geographic cluster remains centered in Blantyre DHO (51 Typhoid cases) and Lilongwe DHO (18 OPD and 11 IPD Typhoid cases), requiring immediate environmental health investigations to locate potential points of source contamination.
When compared to the baseline figures from Epidemiological Week 20, the enteric profile shows a mixed trajectory. Bloody Diarrhoea cases remained stable with a minor 0.6% increase, moving from 783 cases to 788 cases. Conversely, Typhoid fever cases experienced a slight 10.3% decline, dropping from 126 down to 113 cases. Despite this nominal national reduction, the severe concentration of Typhoid cases in Blantyre (45.1% of the national burden) indicates that waterborne and foodborne pathogens are actively spreading within specific metropolitan neighborhoods.
Based on these findings, we recommend that Blantyre, Lilongwe, Mchinji, Kasungu, and Dedza DHOs deploy rapid response teams to conduct systematic water quality monitoring and food safety inspections. Stool and blood cultures must be collected from suspected Typhoid cases to check for potential antimicrobial resistance patterns and guide clinical therapy. Furthermore, environmental health officers must distribute household water treatment chemicals and conduct hygiene sensitization campaigns in high-density markets to break enteric transmission chains.
III. Critical Alerts & Mortality
Cholera and Mpox Status
Epidemiological Week 21 recorded 149 suspected Cholera cases, of which 25 were laboratory-confirmed (or epidemiologically linked) cholera cases, alongside a commendable zero-death record. This stable survival rate reflects the high quality of supportive rehydration and prompt case management within established Cholera Treatment Units (CTUs). On the zoonotic disease front, Mpox surveillance detected 2 suspect alerts, but happily, zero (0) new cases were confirmed, keeping the cumulative national total stable at 157 confirmed cases since the outbreak began in April 2025, with Lilongwe representing 75.8% of cases.
A comparison with Epidemiological Week 20 shows that the Cholera outbreak is evolving toward a highly concentrated phase with a much higher laboratory-confirmation rate. While the absolute number of suspected cholera cases declined from 255 in Week 17 to 145 in Week 20 and then rose slightly to 149 in Week 21, confirmed cholera cases declined from 84 in Week 20 to 25 in Week 21. This reduction in confirmed cases indicates that transmission is highly concentrated in hotspot districts, particularly Blantyre and Chikwawa. Concurrently, Mpox alerts remained stable at 2, with zero new cases confirmed.
To counter this growing Cholera threat, the National Incident Management System must continue to direct emergency water, sanitation, and hygiene (WASH) resources to high-incidence hotspots. In addition, CTU inventories of Oral Rehydration Salts (ORS), IV fluids, and rapid cholera tests must be restocked to prevent shortages. While Mpox reported zero confirmed cases, the 2 new alerts must be investigated within 24 hours. Cross-border coordination with Mozambique and Tanzania must also be maintained to make sure any imported cases are detected and managed promptly.
SARI & Respiratory Mortality
Severe Acute Respiratory Infections (SARI) presented 129 clinical cases and 2 deaths during Epidemiological Week 21. The severe respiratory burden continues to affect several central districts, with Kamuzu Central Hospital (KCH) in Lilongwe reporting 37 cases and 2 deaths, and Dowa DHO reporting 53 cases. This consistent concentration highlights the need for continuous sentinel respiratory surveillance and clinical preparedness within tertiary facilities to handle sudden influxes of acute respiratory cases.
When evaluated against the baseline from Epidemiological Week 20, the SARI surveillance data displays a notable decrease in respiratory morbidity but stable mortality. National SARI cases declined by 22.3%, dropping from 166 cases in Week 20 to 129 cases in Week 21, while SARI-associated deaths remained stable at 2. This persistent level of clinical mortality highlights the circulation of seasonal respiratory pathogens, such as Influenza A/B or RSV, requiring immediate diagnostic and clinical attention.
We recommend that clinical teams at Kamuzu Central Hospital, Dowa District Hospital, and other sentinel hospitals continue to systematically collect nasopharyngeal swabs from SARI patients for PCR diagnostic analysis. Healthcare facilities must ensure that pediatric oxygen delivery systems, clinical nebulizers, and essential respiratory therapeutics remain fully functional. Furthermore, clinicians must continue to document and report SARI cases on the OHSP, allowing public health teams to identify and respond to any new respiratory anomalies quickly.
IV. Vaccine Preventable Diseases
Measles & VPD Surveillance Distribution
Vaccine-Preventable Disease (VPD) surveillance remains a high-priority public health activity, with cumulative confirmed Measles cases rising significantly to 366 across 23 districts in 2026. This week recorded 84 new Measles alerts, emphasizing the persistent transmission risk in hotspot districts, with Balaka reporting the highest proportion at 21.9% (80 cumulative cases). Under the IDSR framework, Acute Flaccid Paralysis (AFP) surveillance recorded 6 cases, and Meningococcal meningitis recorded 26 cases, highlighting the need for sustained immunization coverage and active case searching.
When compared to Epidemiological Week 20, the VPD surveillance profile displays a highly concerning escalation in Meningococcal meningitis and AFP. While weekly Measles alerts declined from 108 cases in Week 20 to 84 cases in Week 21, the cumulative confirmed Measles cases remained stable. Conversely, weekly AFP alerts doubled from 3 in Week 20 to 6 in Week 21, reflecting high surveillance sensitivity. Most significantly, suspected Meningococcal meningitis cases experienced a sharp surge, jumping from 7 cases in Week 20 to 26 cases in Week 21, demanding immediate laboratory investigation.
We recommend that the Expanded Programme on Immunisation (EPI) immediately schedules targeted supplemental immunization activities (SIA) in Balaka and other high-burden districts to interrupt Measles transmission. For the 6 reported AFP cases, district coordinators must ensure that dual stool samples are collected and sent to the laboratory under strict cold chain conditions. To prevent further Meningococcal meningitis spread, healthcare facilities must strengthen routine surveillance, prioritize lumbar punctures for suspected cases, and ensure immediate diagnostic sample collection.
V. Summary of Recommendations
1. Reporting Quality & District Targets
Balaka, Dowa, Karonga, and Zomba DHOs must implement immediate data validation procedures to improve completeness and timeliness back to target levels of 80% or greater, with Zonal Officers verifying data immediately within the OHSP platform.
2. Signal Verification & Risk Assessment
All districts should strengthen the recording and reporting of community-reported Event-Based Surveillance (EBS) signals in OHSP. District Rapid Response Teams (DRRTs) must conduct rapid risk assessments for all verified signals without delay.
3. AEFI Safety Investigation
Mzimba North DHO is directed to perform a detailed vaccine safety investigation on the 52 reported Adverse Events Following Immunization (AEFI) to maintain high community trust in routine childhood immunizations.