After becoming infected with SARS-CoV-2, the majority of people recover in a couple of weeks. For a significant number of patients, though, symptoms can hang on for more than four months, a condition known as long COVID. The National Institutes of Health (NIH) announced yesterday (September 15) that it has awarded a $470 million grant to the REsearching COVID to Enhance Recovery (RECOVER) Initiative to study 40,000 people for more insights into the mechanisms behind the condition, along with possible treatments.

See “Mechanisms of Long COVID Remain Unknown but Data Are Rolling In

In June, the NIH announced the creation of the RECOVER Initiative to study how and why some people with past SARS-CoV-2 infections experience symptoms such as fatigue, loss of taste and/or smell, coughing, and mental fog for months on end. RECOVER now boasts more than 100 researchers from more than 30 institutions, and close to half a billion dollars in funding.

“We know some people have had their lives completely upended by the major long-term effects of COVID-19,” NIH Director Francis Collins says in the press release. “These studies will aim to determine the cause and find much needed answers to prevent this often-debilitating condition and help those who suffer move toward recovery.”

Beginning next month, RECOVER will recruit 30,000–40,000 adults and children from the onset of COVID-19 for a period of 12 months. It is estimated that 10 percent to 30 percent of people who become ill will develop long COVID, though the study hopes to better quantify its prevalence.

Other questions the study aims to answer include who is most likely to develop long COVID and why, along with exploring COVID-19’s potential role in contributing to other chronic illnesses.

The study’s design has its critics. Diana Berrent, founder of the long COVID patient group Survivor Corps, tells Science she believes that widespread vaccination will make it difficult to recruit enough patients to the study. “The people who are just getting Long Covid now because they’re not vaccinated are not the same people who are going to enroll in an NIH longitudinal study,” she says.