HIV viral failure in pregnancy — DTM&H MCQ

Correct answer: B — Switch efavirenz to dolutegravir and recheck VL in 4 weeks

Option B, switching efavirenz to dolutegravir and rechecking viral load in 4 weeks, is correct because a viral load of 850 copies/mL at 24 weeks in a woman on adherent TDF/3TC/EFV represents virological non-suppression that must be corrected before delivery to prevent mother-to-child transmission. Efavirenz has a low genetic barrier to resistance, so persistent low-level viraemia despite adherence should prompt an empirical switch to a high genetic barrier integrase inhibitor rather than continued observation. Dolutegravir achieves rapid, potent viral suppression and is recommended in pregnancy once gestation is confirmed beyond the first trimester, with close viral load monitoring (typically 2 to 4 weeks after any regimen change) to confirm response. Acting promptly maximises the chance of an undetectable viral load by delivery, which is the key determinant of vertical transmission risk. Why the other options are wrong: C. Continue current regimen as VL is low: 850 copies/mL is not virologically suppressed (target is under 50 copies/mL); leaving a failing NNRTI-based regimen unchanged in pregnancy risks progression to overt failure and higher transmission risk. E. Add raltegravir as intensification: intensifying a failing regimen without addressing the underlying resistant backbone drug (efavirenz) does not correct the problem and is not standard practice; a switch, not addition, is required. D. Perform resistance testing and wait for results: resistance testing is reasonable to send, but waiting for results before acting delays effective treatment in a time critical pregnancy; empirical switch to dolutegravir should not be deferred. A. Switch to a PI-based regimen: protease inhibitor regimens have a slower and less potent viral load decline than dolutegravir and are not first-line for this indication in current pregnancy guidance. Key point: In pregnancy, detectable viral load on an NNRTI-based regimen warrants prompt empirical switch to dolutegravir with early viral load recheck, not watchful waiting or resistance-result delay.

Reference: BHIVA guidelines on the management of HIV in pregnancy and postpartum, 2020 (3rd interim update, 2024), section on detectable viral load in pregnancy: optimise regimen to include dolutegravir with close viral load monitoring. https://bhiva.org/wp-content/uploads/2024/10/BHIVA-Pregnancy-guidelines-2020-3rd-interim-update.pdf