New Insights into Persistent SARS-CoV-2 Infections and Long COVID

A recent study published in Nature has put the spotlight on persistent SARS-CoV-2 infections, their prevalence, and their connection to long COVID. The study reveals that these persistent infections are more common than previously believed, and are linked to a higher likelihood of long COVID. Furthermore, reinfections with genetically similar viruses are found to be rare.

Persistent Infections and Post-COVID Symptoms

The study, which involved 6551 patients diagnosed with COVID-19 at a medical institution in Hiroshima from March 2020 to July 2022, aimed to explore the natural course of post-COVID symptoms and reveal the prevalence and duration of each symptom in both adults and children. The results showed that the prevalence of post-COVID symptoms was 78.4% in adults and 34.6% in children upon initial recovery, and decreased to 31.0% and 6.8% after over one year.

Independent risk factors for symptoms lasting over three months included age, being female, having diabetes mellitus, infection during the Delta variant period, and current smoking. The severity of the disease was classified into four categories, and the epidemic periods were categorized based on the dynamics of major variants in Hiroshima.

Persistent Infections and Long COVID

Another study led by the University of Oxford used data from the Office for National Statistics Covid Infection Survey (ONS-CIS) and found that a high proportion of SARS-CoV-2 infections in the general population lead to persistent infections lasting a month or more. Between 0.1-0.5% of all infections may become persistent and last for at least 60 days. Individuals with persistent infections were 55% more likely to report having Long-COVID symptoms more than 12 weeks since the start of the infection.

The Role of Mutations in Persistent Infections

Interestingly, the study also found that certain individuals showed an extremely high number of mutations, including mutations that define new coronavirus variants, alter target sites for monoclonal antibodies, and introduce changes to the coronavirus spike protein. However, most individuals carried a smaller number of mutations, suggesting that not every persistent infection will be a potential source for new concerning variants.

Implications of the Findings

The findings of these studies shed light on the implications of persistent infections and their association with long-term COVID symptoms. The higher likelihood of long COVID in persistent SARS-CoV-2 infections underscores the importance of continued surveillance, research, and patient care to manage the ongoing pandemic effectively. The identification of individuals with persistent SARS-CoV-2 infections and higher odds of self-reporting long COVID through viral sequence data further emphasizes the need for robust data collection and analysis in tracking and understanding the virus and its impacts.