The primary identified meta-analysis of how SARS-CoV-2 variant kind and time since an infection affect long-COVID signs ties Omicron to mind fog and paresthesia (numbness and tingling), whereas earlier variants have been extra prone to trigger shortness of breath and lack of scent.
The research additionally places the prevalence of the situation at 29%, although it dropped to 23% as soon as the Omicron pressure began to dominate.
Investigators in Manila, the Philippines, led the research, which concerned looking out six databases from December 2019 to December 2025 for research of adults identified as having lengthy COVID. To estimate pooled prevalence, the crew stratified the info by variants of concern (VoC) and follow-up (much less or greater than six months). The research have been of cross-sectional, case-control, potential cohort, and retrospective cohort design, and all however one relied on affected person self-report.
Amongst all variants recognized, Alpha, Beta, Gamma, Delta, and Omicron have been thought of VoC. “These VoC have been manifested with numerous pathologic phenotypes resembling heterogeneous illness severity, resistance to neutralizing antibodies, reinfection charges, and vaccine effectiveness,” the research authors wrote.
The research findings have been printed this week within the Worldwide Journal of Infectious Ailments.
Larger prevalence earlier than Omicron
The typical participant age was 46.7 years, 41.2% have been males, and the typical vaccination protection was 69.6%. Probably the most prevalent pre-infection persistent circumstances have been hypertension (24.2%), weight problems (20.0%), and diabetes (8.7%)
The pooled prevalence of lengthy COVID amongst 35 research from 19 nations involving 159,000 whole contributors was 29.4%, with greater prevalence of lengthy COVID within the pre-Omicron (35.5%) than within the Omicron (22.8%) interval. The best prevalence was throughout the Beta wave (59.5%), and the bottom was tied to the wild-type virus (18.3%). After excluding information units with combined or unspecified VoC, the general prevalence of lengthy COVID was 28.5%.
The long-COVID pooled prevalence at lower than six months after an infection (27.3%) was corresponding to that at six months or later (29.9%). Impaired sleep (32.5%), headache (19.8%), and rash (6.5%) have been extra prevalent within the six months after an infection than at six months or later. In distinction, malaise (normal unwellness; 33.1%) and problem swallowing (12.1%) have been extra widespread after six months. In 29.9% of circumstances, signs lasted greater than six months.
Want for tailor-made administration methods
Throughout all variant durations, fatigue was the commonest long-COVID symptom, adopted by mind fog, shortness of breath, and sleep issues. Pre-Omicron variants have been tied to shortness of breath and lack of scent, whereas Omicron was linked to mind fog and paresthesia. Most signs didn’t wane appreciably over six months.
Our findings underscore that post-COVID-19 situation shouldn’t be considered as a uniform syndrome however reasonably as a dynamic and multifaceted situation formed by VoC and temporal elements.
Charges of impaired sleep have been greater within the early pre-Omicron period however improved over time. In distinction, coronary heart palpitations and eye issues elevated in later pre-Omicron durations.
“Our findings underscore that post-COVID-19 situation shouldn’t be considered as a uniform syndrome however reasonably as a dynamic and multifaceted situation formed by VoC and temporal elements,” the authors wrote. “The shifting symptomatology profiles recommend that totally different mechanisms could drive the persistence of post-COVID signs throughout variants and over time.”
Future analysis ought to concentrate on harmonizing research methodologies and definitions to seize the true burden, variability, and trajectory of lengthy COVID, they stated.
“Submit-COVID situation stays a burden regardless of vaccination,” the crew concluded. “Distinct symptomatology patterns throughout VoC and timelines spotlight the necessity for tailor-made administration methods to mitigate long-term international impacts.”