# Monitoring COVID-19 occurrence in a resource-limited setting – COVID-19 sentinel surveillance in Malawi

## TL;DR

This study describes an active surveillance system for monitoring COVID-19 in Malawi, showing higher infection rates among symptomatic and asymptomatic individuals in health facilities compared to entry points.

## Contribution

The study introduces an active sentinel surveillance system to improve real-time monitoring of SARS-CoV-2 in a resource-limited setting.

## Key findings

- Higher SARS-CoV-2 positivity rates were observed in health facilities compared to entry points.
- Positivity trends were similar among symptomatic and asymptomatic individuals.
- Active surveillance proved valuable during low incidence periods.

## Abstract

The routine COVID-19 surveillance in Malawi that relied on retrospective reporting could not efficiently steer timely measures to the rapidly evolving pandemic. To monitor real-time changes in infections and inform the COVID-19 response, we implemented an active sentinel surveillance system from July to December 2022. Symptomatic and asymptomatic patients with SARS-CoV-2 in selected health facilities (HFs) and anyone aged ≥5 years entering at Point of Entry (PoEs) sites were eligible to participate. Self-reported epidemiological and clinical data, and nasopharyngeal specimens were collected from 9,305 participants. A higher overall SARS-CoV-2 RT-PCR positivity rate was observed at HFs, 8.9% among symptomatic and 6.5% among asymptomatic patients, versus 3.5% at PoEs. The positivity trends among symptomatic and asymptomatic patient groups showed a similar pattern throughout the period. This active surveillance complemented routine surveillance, especially during a low incidence period and highlighted the need to target both symptomatic and asymptomatic populations.