Impact of SARS-CoV-2 viral load on restrictive spirometry patterns in mild COVID-19 recovered middle-aged individuals: a six-month prospective study

Abstract

Background Long term respiratory complications of Corona Virus Disease-2019 (COVID-19) are of great concern. Many studies have reported altered respiratory patterns in COVID-19 recovered individuals and most of them were from severe to critically ill patients. The association of viral load at the time of infection with symptoms of long COVID-19 specifically on pulmonary functions after months of recovery is still not known. This study was aimed to assess the impact of SARS-CoV-2 viral load during mild-moderate COVID-19 disease on pulmonary functions in middle-aged population after 6–8 months of acute infection. Methods This study included 300 (102 healthy controls and 198 COVID-19 recovered) individuals between age 30–60 of either gender. Mild-moderate COVID-19 recovered individuals were recruited between a period of 6–8 months post-acute infection. Spirometry was performed with MIR-Spirolab-III. The association of spirometry pattern was compared with SARS-CoV-2 viral loads during acute infection. Results We observed up to 70% of the participants presented with either shortness of breath (11.5%), body aches (23.5%), recurrent cough (4.4%), recurrent respiratory infections (9.5%) and/or fatigue (33.3%) at follow up. In our study, 35.5% of COVID-19 recovered individuals had abnormal respiratory patterns (33.5% had restrictive and 2% had obstructive patterns). Viral load ≤ 20 CT value was associated with restrictive respiratory patterns ( p = 0.004). No association was found between viral load and disease severity ( p = 0.23). Conclusion In this study, we found one third of mild-moderate COVID-19 recovered individuals have restrictive respiratory patterns after 6–8 months of recovery. These findings had a strong association with SARS-CoV-2 viral loads during acute infection which has been reported for the first time in our study. Studying the relationship between viral load and pulmonary functions can contribute to identifying potential risk factors for long COVID and developing preventive measures to mitigate the long-term impact on lung health. Clinical trial number Not applicable.