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