Virus World

To understand the roles of acute phase viral dynamics and host immune responses in PASC, we enrolled 136 participants within 5 days of their first positive SARS-CoV-2 real-time PCR. Participants self-collected nasal specimens up to 21 times within the first 28 days after symptom onset; Interviewer-administered clinical questionnaires and blood samples were collected at enrollment and days 9, 14, 21, 28, and month 4 and 8 post-symptom. Defining PASC as the presence of any symptom new or worse since infection reported at their 4-month visit, we compared viral markers (quantity and duration of viral RNA load, infectious viral load, and plasma N-antigen level) and host immune markers (IL-6, IL-10, TNF-a, IFN-a, IFN-g, MCP, IP-10, and Spike IgG) over the acute period.

In comparison to those who fully recovered, those who developed PASC demonstrated significantly higher maximum levels of SARS-CoV-2 RNA, infectious virus, and N-antigen, longer duration of viral shedding, and lower Spike-specific IgG levels within the first 10 days of the acute phase of illness. No significant differences were identified among a panel of host immune markers, though there was a trend toward higher initial levels of certain markers (e.g., MCP-1, IFN-a, and IFN-g) in those who went on to develop PASC. Early viral dynamics and the associated host immune responses play a role in the pathogenesis of PASC. These findings highlight the importance of understanding the early biological markers from acute SARS-CoV-2 infection in the natural history of PASC.

Preprint available in medRxiv (July 16, 2023):

https://doi.org/10.1101/2023.07.14.23292649