A new study of more than 4,700 people from the Collaborative Group of Cohorts for COVID-19 Research (C4R) shows that more than one in five people who became infected with COVID from 2020 to 2023 did not recover within 90 days of infection. The study also found that people who were vaccinated and infected with the Omicron variant had a milder infection and recovered more quickly. The research, led by investigators at Columbia University Vagelos College of Physicians and Surgeons, was published in 2014. JAMA Network Open,
“Our study underscores the important role of vaccination against COVID, not only in reducing the severity of infection but also in reducing the risk of long COVID,” says Elizabeth C. Oelsner, PhD, lead author of the study and the Herbert Irving Associate Professor of Medicine at Columbia.
Currently, it is still unclear why some people suffer from “long Covid,” or symptoms and conditions that develop, persist, or recur weeks or months after the initial infection. However, the new study provides insight into people who are at higher risk of experiencing long-lasting symptoms.
Women and adults with heart disease before the pandemic were less likely to recover from Covid three months later. Other pre-pandemic health conditions such as chronic kidney disease, diabetes, asthma, chronic lung disease, depressive symptoms and a history of smoking were associated with longer recovery times, though the researchers found these associations were no longer significant after taking into account gender, heart disease, vaccination and variant risk.
“Participants with pre-pandemic health conditions had longer recovery times. When adjusting for all pre-pandemic conditions simultaneously, only clinical CVD was associated with recovery; infection severity attenuated this association by 20.0%, suggesting the importance of alternative pathways, such as systemic inflammation or endotheliopathy,” the researchers wrote.
Other groups disproportionately affected by long COVID — sometimes called post COVID-19 status (PCC) — were American Indian and Alaska Native study participants, who experienced more severe infections and longer recovery periods.
“Additional research is needed to determine the extent to which the pandemic has exacerbated social and health inequities in the US, including among Indigenous communities,” the investigators said. “Including racially and ethnically diverse participants in (long COVID) mechanistic research and clinical trials is essential to identify and equitably deliver interventions.”
The results of the new analysis were consistent with previous studies about the burden of PCC in the US population, namely the Researching COVID to Enhance Recovery (RECOVER) initiative – a large, prospective, case-control study of PCC. RECOVER had a longer follow-up period (six months vs 90 days) and patient self-reporting of 12 symptoms found a 10% prevalence of symptom score-defined PCC at six-month follow-up.
The team also said their research was consistent with data from earlier efforts that showed women had worse recovery rates than men despite lower rates of severe acute illness. “This finding may be due to reporting bias based on gender, although other possibilities should also be considered,” the team said. “Gender differences in PCC risk, and particularly PCC sub-phenotypes characterized by neurologic, musculoskeletal, and autoimmune conditions, may be explained by several mechanisms, including differences in immune response and a higher risk of autoreactivity and thrombosis in women (compared to men), which deserve further study.”