A recent breakthrough in understanding the Covid-19 pandemic has shed light on the crucial role of persistent infections in the evolution of the virus… and to understand the mechanisms underlying long Covid and the pandemic.
A study recently published in the journal Nature, reveals that many SARS-CoV-2 infections in the general population become persistent, lasting a month or more. This discovery sheds new light on the dynamics of the Covid-19 pandemic, particularly with regard toemergenceemergence new variants and the challenges posed by long Covid.
Characteristics of persistent infections
Until recently, the dominant hypothesis attributed the genesis of virus variants, such as Alpha and OmicronOmicron, prolonged infections in immunocompromised people. However, the extent and implications of persistent infections in the general population remained poorly understood. This new study fills this gap by analyzing data from the UK Office for National Statistics Covid Infection Survey (ONS-CIS), involving more than 90,000 participants and extending from November 2020 to August 2022. Of this total, 3,603 people provided two or more positive samples, allowing sequencing of the virus. Of these, 381 were identified with persistent infections lasting a month or more, of which 54 lasted at least two months.
Researchers estimate that between 0.1% and 0.5% of all SARS-CoV-2 infections can become persistent and last 60 days or more. Surprisingly, some of these persistent infections were due to variants of the virus that have since disappeared in the general population, highlighting the rarity of reinfection with the same variant, likely thanks toimmunityimmunity developed by the host.
A link between persistent infections, symptoms of long Covid and variants?
The study also examined the relationship between persistent infections and long Covid, revealing that people with persistent infections were 55% more likely to report symptomssymptoms of long Covid more than 12 weeks after the start of the infection, compared to those who had shorter infections. This suggests a possible link between viral persistence and prolonged manifestations of Covid-19.
Researchers observed a high number of mutations in certain individuals, including those characterizing new variants and modifying the proteinprotein Virus spike. However, the majority of persistent infections did not have large numbers of mutations, indicating that not all persistent infections are necessarily sources of variants of concern.
This study highlights the importance of surveillance genomicsgenomics community to understand the evolution of SARS-CoV-2 and its implications for public health, particularly with regard to long Covid and the emergence of new variants. It provides essential insights into prolonged viral dynamics and their potential effects on pathologypathology of long Covid.