(B-275) Adherence to Recommended Antiviral Treatment Guidelines for COVID-19 and Influenza during Pregnancy

Background: Pregnancy is a risk factor for severe COVID-19 and influenza. Antiviral medications, including nirmatrelvir/ritonavir (Paxlovid®, NMV/r) and oseltamivir (Tamiflu®) are recommended to treat COVID-19 and influenza in an outpatient setting. Despite these recommendations, little is known about prescribing behaviors and patient acceptance of these medications during pregnancy.

Objectives: To determine the proportion of patients who are prescribed and treated with recommended antiviral medications for COVID-19 and influenza during pregnancy.

Methods: We conducted a retrospective cohort study at Kaiser Permanente Southern California, including all pregnancies with a date of delivery on or after 22 December 2021 (i.e., date of NMV/r availability) through 30 June 2024. COVID-19 and influenza diagnoses were identified during pregnancy using ICD-10-CM coded outpatient encounters in electronic health records (EHRs). Medications prescribed and dispensed were identified in patient EHRs. We estimated the proportion of pregnancies diagnosed with COVID-19 and/or influenza who were prescribed and treated with (i.e., dispensed) a recommended antiviral medication.

Results: We identified 9,615 pregnancies with a COVID-19 diagnosis and 1,597 with an influenza diagnosis; 11% (n=1,036/9,615) of pregnancies with a COVID-19 diagnosis were prescribed and 6.7% (n=642/9,615) received NMV/r. In contrast, 57% (n=909/1,597) of pregnancies with an influenza diagnosis were prescribed and 44% (n=704/1,597) received oseltamivir. Treatment rates for NMV/r increased over time from 3.5% in 2022 to 19% in 2024, while annual treatment rates for influenza ranged between 38% and 47%. Among pregnant patients with other comorbidities (i.e., asthma, cardiopulmonary disease), treatment rates for COVID-19 remained low (8.0%) and higher treatment rates were observed for influenza (45%). Regardless of the trimester of pregnancy at the time of COVID-19 diagnosis, treatment rates were 11%. In contrast, treatment rates increased from 49% for pregnancies with an influenza diagnosis during the first trimester to 63% for pregnancies with a diagnosis during the third trimester.

Conclusions: Four-in-five pregnant patients with COVID-19 are not receiving recommended antiviral medications, yet nearly one-in-two pregnant patients with influenza receive recommended treatment. Low treatment rates for COVID-19 appear to be the result of a combination of prescriber and patient behaviors. Given the large portion of pregnant patients who are unvaccinated and untreated for COVID-19, risk of progression to severe disease remains high. Targeted work to increase access to recommended antiviral medications during pregnancy, especially for COVID-19, is needed.