Effect of hospitalization, vaccination unclear
Ms. Ballering said it’s unclear from this data whether vaccination or whether a person was hospitalized would change the prevalence of persistent symptoms.
Because of the period when the data were collected, “the vast majority of our study population was not fully vaccinated,” she said.
However, she pointed to recent research that shows that immunization against COVID is only partially effective against persistent somatic symptoms after COVID.
Also, only 5% of men and 2.5% of women in the study were hospitalized as a result of COVID-19, so the findings can’t easily be generalized to hospitalized patients.
The Lifelines study was an add-on study to the multidisciplinary, prospective, population-based, observational Dutch Lifelines cohort study examining 167,729 people in the Netherlands. Almost all were White, a limitation of the study, and 58% were female. Average age was 54.
The editorialists also noted additional limitations of the study were that this research “did not fully consider the impact on mental health” and was conducted in one region in the Netherlands.
Janko Nikolich-Žugich, MD, PhD, director of the Aegis Consortium for Pandemic-Free Future and head of the immunobiology department at University of Arizona, Tucson, said in an interview that he agreed with the editorialists that a primary benefit of this study is that it corrected for symptoms people had before COVID, something other studies have not been able to do.
However, he cautioned about generalizing the results for the United States and other countries because of the lack of diversity in the study population with regard to education level, socioeconomic factors, and race. He pointed out that access issues are also different in the Netherlands, which has universal health care.
He said brain fog as a symptom of long COVID is of high interest and will be important to include in future studies that are able to extend the study period.
The work was funded by ZonMw; the Dutch Ministry of Health, Welfare, and Sport; Dutch Ministry of Economic Affairs; University Medical Center Groningen, University of Groningen; and the provinces of Drenthe, Friesland, and Groningen. The study authors and Dr. Nikolich-Žugich have reported no relevant financial relationships. Dr. Brightling has received consultancy and or grants paid to his institution from GlaxoSmithKline, AstraZeneca, Boehringer Ingelheim, Novartis, Chiesi, Genentech, Roche, Sanofi, Regeneron, Mologic, and 4DPharma for asthma and chronic obstructive pulmonary disease research. Dr. Evans has received consultancy fees from AstraZeneca on the topic of long COVID and from GlaxoSmithKline on digital health, and speaker’s fees from Boehringer Ingelheim on long COVID.
A version of this article first appeared on Medscape.com.