Understanding respiratory illnesses: Flu, COVID-19, or just a cold?

As winter settles in, South Africans are grappling with respiratory illnesses, including flu, COVID-19, and the common cold. Symptoms often overlap, making it hard to distinguish between the three without a test. The National Institute for Communicable Diseases (NICD) reports that the 2026 influenza season started earlier than usual, with A(H1N1)pdm09 and A(H3N2) being the most prevalent subtypes. The NICD also noted that RSV and SARS-CoV-2 cases were detected in both private and public settings.

The key differences lie in the onset and severity of symptoms. Flu typically comes on rapidly, causing high fever, chills, body aches, headache, and fatigue. In contrast, a common cold progresses more gradually, presenting with milder symptoms such as a runny or stuffy nose, sneezing, and sore throat. COVID-19, meanwhile, can mimic both flu and cold symptoms, including fever, cough, sore throat, fatigue, and loss of taste or smell.

Testing is crucial to determine the specific virus causing the illness. While symptoms alone cannot differentiate between flu and COVID-19, at-home multiplex tests can detect both viruses simultaneously. If symptoms persist or worsen, especially for those at higher risk, consulting a healthcare professional for further testing is recommended. Antiviral treatment for flu is most effective when initiated promptly, especially for those with severe symptoms or underlying health conditions.