In a 14‑week pregnant patient with a mild sore throat and pending PCR testing for influenza and SARS‑CoV‑2, is it advisable to prescribe oseltamivir (Tamiflu) or nirmatrelvir‑ritonavir (Paxlovid) if the tests are positive?

Treatment Recommendations for Influenza and COVID-19 at 14 Weeks Gestation

If your patient tests positive for influenza, prescribe oseltamivir (Tamiflu) immediately—it is safe and strongly recommended in pregnancy. If she tests positive for COVID-19, nirmatrelvir-ritonavir (Paxlovid) can be offered after careful discussion of limited pregnancy data, though it appears reasonably safe based on emerging evidence.

Influenza Treatment in Pregnancy

Strong Recommendation for Oseltamivir

Pregnant women with suspected or confirmed influenza should receive oseltamivir regardless of vaccination status, symptom severity, or laboratory confirmation 1. This is a firm recommendation because:

• Pregnancy itself is a high-risk condition for influenza complications, with increased rates of hospitalization, ICU admission, and death 2
• Treatment within 48 hours of symptom onset is ideal, but do not withhold treatment if this window is missed 1
• You can prescribe oseltamivir over the phone based on clinical suspicion alone—do not wait for PCR results 1

Safety Profile in Pregnancy

Oseltamivir has reassuring safety data across multiple studies:

• In 232 maternal exposures, spontaneous abortion rate was 6.1% (7/115), preterm delivery 2.1% (2/94)—all within background rates 3
• Animal studies show no teratogenic effects at therapeutic doses 3
• Transplacental transfer is very limited at normal therapeutic doses 3
• The FDA label states it should be used during pregnancy "only if the potential benefit justifies the potential risk," but the clinical consensus strongly favors treatment given the high maternal morbidity/mortality risk from untreated influenza 4, 1

Dosing

Standard adult dosing: 75 mg twice daily for 5 days. Can be taken with or without food, though taking with food reduces nausea 4.

COVID-19 Treatment in Pregnancy

Conditional Recommendation for Paxlovid

Nirmatrelvir-ritonavir (Paxlovid) can be offered to pregnant women with mild-to-moderate COVID-19 within 5 days of symptom onset, particularly if they have risk factors for severe disease 5, 6. The evidence is more limited than for oseltamivir, but emerging data are reassuring:

Recent Evidence

A 2025 systematic review and meta-analysis of 427 pregnant patients treated with Paxlovid showed 5:

• Hospitalization rate: 2% (95% CI: 1%-5%)
• Drug discontinuation: 0.7%
• No maternal or neonatal deaths
• Mean birth weight: 3186g (normal range)

A 2024 retrospective cohort of 114 pregnant patients taking Paxlovid found 6:

• Well-tolerated with no discontinuations due to side effects
• No ICU admissions
• Most obstetric outcomes similar to untreated group
• Small increases in preeclampsia (9.6% vs 3.7%) and surgical site infections (2.7% vs 0%), though numbers were too small for definitive conclusions

Important Considerations

Pregnancy is a recognized risk factor for severe COVID-19, with increased risks of preeclampsia, preterm delivery, and fetal death 7. The FDA label for Paxlovid does not specifically address pregnancy, but the EPIC-HR trial excluded pregnant women 8.

Critical drug interaction screening is mandatory before prescribing Paxlovid due to ritonavir's extensive CYP3A4 inhibition 8. Review all her medications carefully.

Mild Sore Throat Context

For a patient with only mild symptoms (sore throat), the decision becomes more nuanced:

• For influenza: Still treat with oseltamivir—the risk-benefit strongly favors treatment even with mild symptoms, as influenza can rapidly progress in pregnancy 2, 1
• For COVID-19: The benefit of Paxlovid is greatest in those at high risk of progression. At 14 weeks gestation without other risk factors and only mild symptoms, you could reasonably discuss watchful waiting versus treatment. However, pregnancy itself qualifies as a risk factor 7, so offering treatment is appropriate

Practical Algorithm

1. Prescribe oseltamivir immediately if influenza is suspected—do not wait for PCR results 1
2. If COVID-19 is confirmed and she wants treatment:
   • Verify she's within 5 days of symptom onset
   • Screen for drug interactions thoroughly
   • Discuss limited but reassuring pregnancy data 5, 6
   • Prescribe Paxlovid 300mg/100mg twice daily for 5 days if no contraindications 8
3. If both tests are negative: Supportive care only

Common Pitfalls to Avoid

• Don't delay oseltamivir waiting for test results—treat presumptively for influenza in pregnancy 1
• Don't dismiss mild symptoms—influenza can progress rapidly in pregnant women 2
• Don't forget to check drug interactions before prescribing Paxlovid—ritonavir has extensive interactions 8
• Don't withhold oseltamivir beyond 48 hours—late treatment still provides benefit 1