hospital wastewater surveillance of sars-cov-2 rna: association with covid-19 cases and insights into environmental persistence

Introduction: analyzing municipal wastewater for the presence of sars-cov-2 rna serves as a cost-effective and timely tool for epidemiological surveillance to mitigate virus-related health risks. therefore, this study assessed the presence of sars-cov-2 rna in untreated hospital wastewater and its correlation with covid-19 case numbers over six months at shahidzadeh hospital in southwest iran. materials and methods: in this analytical investigation, a total of 24 grab samples of untreated hospital wastewater were systematically collected over six months, spanning from september 2020 to february 2021. each sample was subsequently processed and analyzed using a reverse transcription quantitative polymerase chain reaction (rt-qpcr) approach, with specific amplification targeting both the rna-dependent rna polymerase (rdrp) gene and the nucleocapsid (n) gene of sars-cov-2.results: all 24 wastewater samples tested positive for sars-cov-2 rna. concentrations ranged between 130 to 490 gene copies/100 ml, with mean values increasing from 247 (september) to 425 (february). rna levels were strongly correlated with hospitalized covid-19 cases (spearman’s p < 0.05, r² = 0.87). conclusion:  these findings highlight the value of hospital wastewater surveillance as a cost-effective epidemiological tool, particularly in settings with limited diagnostic capacity. future research should investigate viral viability and optimize disinfection strategies to reduce potential environmental risk.