This week marks four years since the outbreak of Covid-19 was officially declared a pandemic. One of the most vexing legacies — one that science still hasn't solved — is long Covid. That's the debilitating condition that can develop in the aftermath of an infection. Millions of Americans are living with the often debilitating symptoms that can include brain fog, shortness of breath, and low energy. Some struggle with simple daily living tasks like laundry and cooking. Four years since the pandemic hit, patients with long Covid are still fighting for answers. For sponsor-free episodes of Consider This, sign up for Consider This+ via Apple Podcasts or at plus.npr.org. Email us at considerthis@npr.org.Learn more about sponsor message choices: podcastchoices.com/adchoicesNPR Privacy Policy