Long COVID, referred to clinically as post-COVID condition or postacute sequelae of SARS-CoV-2 infection, may now affect 15% of U.S. adults who have ever had COVID, according to early August data from the U.S. Census Bureau Household Pulse Survey. Yet the condition is still not well defined. Hypotheses abound, but the exact pathology of post-COVID condition remains elusive, leaving health care providers with little guidance for specific treatment.
The Centers for Disease Control and Prevention describes long COVID as "a wide range of new, returning, or ongoing health problems that people experience after first being infected with the virus that causes COVID-19." Symptoms may include fatigue and fever, or present as respiratory, cardiac, neurologic, or digestive disorders. But this hardly constitutes a working definition useful to clinicians trying to connect the dots between prior COVID infection and new or lingering illness.
However, research is underway to define core symptoms of long COVID and how to distinguish them from other non-COVID-related conditions. A recent observational study in the Netherlands, published in the August 6 Lancet, set out to analyze the nature, prevalence, and severity of post-COVID condition, using the World Health Organization's proposed case definition, which states that symptoms usually occur at three months from COVID onset, persist for two months or more, and cannot be explained by an alternate diagnosis.
The researchers compared symptom severity in COVID-positive patients with that of COVID-negative controls at 90 to 150 days, based on participants' responses to repeated digital questionnaires. Using those data, they determined that the core symptoms of post-COVID condition were ageusia, anosmia, difficulty with or painful breathing, chest pain, a lump in the throat, painful muscles, general fatigue, tingling and heaviness of the extremities, and alternating sensations of hot and cold. Headache, itchy eyes, dizziness, back pain, and nausea were not found to be significantly increased during that period.
Limitations of the study included possible underestimation of the prevalence of COVID-19 and reliance solely on a cohort of adults in the northern area of the Netherlands. The authors described their findings as merely a starting point for a working definition of post-COVID condition. More research is needed to hone that definition in order to establish best practice guidelines for treatment.-Gail M. Pfeifer, MA, RN