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

Objectives: We aim to study the relative viral load using salivary 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 thirty-seven pregnant women, seventeen received Paxlovid, and twenty 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 ( = 0.005). Following treatment, the median salivary viral load decreased by 13.40 cycle threshold values in the Paxlovid group (from a median of [Day 0 Ct] to [Day 4/5 Ct]), compared to a change of -1.59 cycle threshold values in the no-antiviral group (from a median of [Day 0 Ct] to [Day 4/5 Ct]) ( = 0.021). The detection rate of coronavirus disease 2019 using salivary polymerase chain reaction was 83.8% (31/37).

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.