- Antiviral drugs for postexposure prophylaxis (PEP) represent a potential strategy for preventing secondary COVID-19 transmission following initial contact exposure.
- Clinical trials exploring prophylactic hydroxychloroquine are either underway or recruiting ( China , Spain , and South Korea).
- A multicentre study is evaluating standard of care (SOC) plus remdesivir; plus lopinavir and ritonavir; plus lopinavir, ritonavir, and interferon-beta; or plus hydroxychloroquine.
- Trial launched March 23 in France with 800 patients hospitalized with COVID-19; enrollment will scale to 3200 European patients.
Why this matters
- Standard public health interventions (social distancing, cordon sanitaire, contact tracing) alone are insufficient.
- Early pharmacological modeling, anecdotal reports suggest potential benefit of hydroxychloroquine (at approved doses) against SARS-CoV-2 infection and COVID-19, and possible amelioration of viral shedding.
- Strategies to protect individuals at high risk for COVID-19 acquisition (especially health care workers, close contacts) are urgently needed.
- Secondary COVID-19 attack rates are ~15% among households, ~10% among close contacts.
- Based on prior clinical experience (e.g., rifampicin PEP to prevent invasive meningococcal infection following contact with index case), starting PEP immediately post-COVID-19 symptom onset may reduce viral shedding in respiratory secretions (those in sputum peak ~5-6 days post-symptom onset, lasting up to 14 days).
- Targeted PEP might reduce infection risk among close contacts.