Detection of Severe Acute Respiratory Syndrome Coronavirus 2 in Pregnant Women Treated with Nirmatrelvir/Ritonavir (Paxlovid) Using Saliva Polymerase Chain Reaction: a Prospective Cohort Study

Abstract: Objectives We aim to study the relative viral load using saliva polymerase chain reaction among pregnant women treated with Paxlovid. Methods Pregnant women with coronavirus disease 2019 were allocated to two groups: those receiving Paxlovid and those receiving no antiviral agents. We compared the nasopharyngeal and salivary relative viral loads and their changes in saliva specimens. Results Among the 38 pregnant women, seventeen received Paxlovid, and 21 received no antiviral agents. The viral cycle threshold value of saliva was significantly higher than that from nasopharynx, with a median ± interquartile range of 26.44 ± 7.68 versus 17.6 ± 9.6 in the Paxlovid group (p = 0.005). Following treatment, the Paxlovid group showed a significant decrease in relative saliva viral load (cycle threshold value on Day 4/Day 5 minus Day 0) compared to the non-antiviral group (13.40 ± 5.64 versus -1.59 ± 9.63, p = 0.021). The detection rate of coronavirus disease 2019 using salivary polymerase chain reaction was 81.6% (31/38). Conclusions This study showed that saliva is a useful diagnostic tool for coronavirus disease 2019 in pregnant women, and a significant decrease in the relative viral load of saliva was observed in those treated with Paxlovid.