Studies comparing SARS-CoV-2 nasopharyngeal (NP) viral load (VL) according to virus variant and host vaccination status have yielded inconsistent results. We conducted a single center prospective study between July and September 2021 at the drive-through testing center of the Toulouse University Hospital. We compared the NP VL of 3775 patients infected by the Delta ( n = 3637) and Alpha ( n = 138) variants, respectively. Patient’s symptoms and vaccination status (2619 unvaccinated, 636 one dose and 520 two doses) were recorded. SARS-CoV-2 RNA testing and variant screening were assessed by using Thermo Fisher ® TaqPath™ COVID-19 and ID solutions ® ID™ SARS-CoV-2/VOC evolution Pentaplex assays. Delta SARS-CoV-2 infections were associated with higher VL than Alpha (coef = 0.68; p ≤ 0.01) independently of patient’s vaccination status, symptoms, age and sex. This difference was higher for patients diagnosed late after symptom onset (coef = 0.88; p = 0.01) than for those diagnosed early (coef = 0.43; p = 0.03). Infections in vaccinated patients were associated with lower VL (coef = −0.18; p ≤ 0.01) independently of virus variant, symptom, age and sex. Our results suggest that Delta infections could lead to higher VL and for a longer period compared to Alpha infections. By effectively reducing the NP VL, vaccination could allow for limiting viral spread, even with the Delta variant.
【저자키워드】 COVID-19, SARS-CoV-2, vaccination, delta variant, Viral load, 【초록키워드】 Evolution, SARS-COV-2 infection, Prospective Study, variant, Infection, Delta, Symptom, delta variant, viral spread, virus, Symptoms, variants, infections, Viral, nasopharyngeal, Patient, Alpha, SARS-CoV-2 RNA, university, dose, lead, Vaccination Status, symptom onset, single center, doses, Thermo Fisher, Host, assays, diagnosed, conducted, reducing, age and sex, were recorded, were assessed, 【제목키워드】 Delta, load, influence, the SARS-CoV-2,