Study Suggests Long COVID-19 Is Prevalent, Risk Varies Among Populations

Findings from a recent study suggest that long COVID is highly prevalent, although the risk varies among subgroups and vaccination may reduce this risk.

Some individuals with COVID-19 can experience symptoms beyond 1 month, and some may report symptoms at least 6 months later, according to the study, published by JAMA. The World Health Organization has defined long COVID as generally occurring 3 months from the onset of COVID-19 with symptoms that last for at least 2 months.

Prevalence estimates vary widely due to variability in the definition and sampling frame. A self-report symptom tracking study with 4182 individuals found rates of symptomatic persistence of 13.3% at 1 month and 4.5% at 2 months. Additionally, a study in the United Kingdom among 20,000 individuals with a positive SARS-CoV-2 test found that 13.7% reported symptom persistence at 12 weeks based on a single survey question.

To investigate these questions further, researchers included data collected from 8 waves of the COVID States Project, a large-scale internet survey conducted for an academic consortium approximately every 6 weeks between February 5, 2021, and July 6, 2022, including all 50 states and the District of Columbia. Participants were 18 years of age or older who resided in the United States.

Without reweighting the survey sample, the investigators found that the 16,091 survey respondents reporting test-confirmed COVID-19 at least 2 months prior had a mean age of 40.5 years, 62.6% were women, 5.1% were Asian, 11.3% were Black, 9.6% were Hispanic, and 71% were White. From this cohort, 14.7% reported continued COVID-19 symptoms more than 2 months after acute illness.

The researchers then reweighted the sample to reflect national sociodemographic distributions and found that individuals meeting the criteria for long COVID represented 13.9% of those who had tested positive for COVID-19, including 12.6% of Asian adults, 9.7% of Black adults, 15.3% of Hispanic adults, and 15.5% of White adults.

In a reweighted analysis of all survey participants to estimate the proportion of the US adult population who met the criteria for current long COVID, these individuals represented 1.7% of US adults, including 1.3% of men, 2% of women, 0.7% of Asian adults, 1% of Black adults, 2% of Hispanic adults, and 1.8% of White adults.

The investigators then examined the association of the predominant variant at the time of infection and of vaccination prior to acute illness with risk for long COVID. Compared with ancestral COVID-19, infection during periods when the Epsilon or Omicron variant were predominant was associated with a diminished likelihood of long COVID.

Additionally, completion of the primary vaccine series prior to acute illness was associated with a lower risk of long COVID. However, partial vaccination was not associated with a significant reduction in the risk in fully adjusted models.

Taken together, the findings provide an estimate of the mean point prevalence of long COVID in a large, representative population sample of individuals in the United States. The authors said the findings support the potential protective association of vaccination in reducing long COVID risk, although it does not appear to eliminate the risk. If confirmed in prospective studies, the results may help facilitate risk stratification, with the goal of early intervention to minimize the effect of long COVID.

REFERENCE

Perlis R, Santillana M, Ognyanova K, et al. Prevalence and Correlates of Long COVID Symptoms Among US Adults. JAMA Netw Open. 2022;5(10):e2238804. doi:10.1001/jamanetworkopen.2022.38804. Accessed November 14, 2022.