A study by the Centers for Disease Control and Prevention (CDC) found that people who tested positive for COVID-19 reported having long-term symptoms 1.5 times more common than those who gave negative.
Nearly 66% of people who tested positive for the virus reported that at least one of the symptoms related to COVID-19 lasted more than four weeks, compared with 42.9% of people who always tested negative.
The non-probability-based survey, conducted April 9-23 by Porter Novelli Public Services, aimed to collect a national sample of American adults to compare the prevalence of long COVID-19 symptoms.
Of the 3,135 adults who responded that COVID-19 had been tested since January 2020, nearly 700, a weighted 22.2%, reported that they had never received a positive test result, compared with 2,437 who they always gave negative. Another 2,750 said they were never tested and were not included in the CDC analysis.
A total of 86.5% of respondents who tested positive and 61.7% of those who tested negative said they had some initial symptoms. A higher proportion of patients confirmed with COVID-19 who had an initial symptom said it lasted more than four weeks than people who tested negative and had an initial symptom.
Fatigue was the most common symptom among patients confirmed with COVID-19, with 22.5% reporting it compared with 12% of those who tested negative. Respondents who had tested positive also reported a higher prevalence of symptoms such as a change in smell or taste, shortness of breath, cough, and headache.
The CDC’s Weekly Morbidity and Mortality Report (MMWR) described the long COVID-19 as an “emerging public health concern that is not well understood.”
Several studies have attempted to pinpoint the percentage of COVID-19 survivors who develop long-term COVID-19, although early results have covered a wide range. But the CDC noted that few studies on the long COVID-19 have compared it to the adult population that tested negative, “limiting the ability to assess the prevalence of underlying symptoms.”
“Estimating the population-level frequency of specific long-term symptoms among the general population and patients infected with SARS-CoV-2 could help healthcare professionals better understand the types and prevalences of symptoms that their patients may experience and could help guide health systems in preparing care management strategies for patients with post-COVID conditions, ”says the MMWR.
The agency said its survey could help address the long-term COVID-19 and further promote vaccinations.
Only 28.3% of those who tested positive reported receiving at least one dose of the COVID-19 vaccine, while 39.4% of those who tested positive received at least one vaccine. All adults were officially eligible for the vaccine on April 19th.
A higher proportion of patients confirmed with COVID-19, with 28.7%, said they thought the vaccine improved their long-term symptoms, compared with 15.7% of those who refused.
The CDC noted that the study could not determine the accuracy of the COVID-19 tests, so false positive and false negative results may have affected the results.