Early terminated PEP RCT comparing HC
Q and vitamin C with 781 patients (83% household contacts), reporting no significant differences.
The study has not been released yet but partial details were provided in a presentation at IDWeek.
The study enrolled people with their last exposure within 4 days, i.e., if someone was exposed for 30 days in a row, they could be enrolled anywhere from day 1 to day 34. Therefore many were likely infected earlier than the enrollment date. Note that PCR has a very high false negative rates, e.g., 100% on day 1 and 67% on day 4 here .
50% of infections were detected by day 4. With the PCR false negatives and treatment delays it is likely that a majority of infections happened before enrollment or before HC
Q can reach therapeutic levels.
Therapy started one day after enrollment and study supplies were sent to the participant "either by courier or mail". So the arrival time of the medication is not specified. In Boulware et al., the shipping delay was up to 3.5 days, if the delay is similar here the overall delays may be:
time since first exposure - unlimited
time to enrollment - up to 4 days
time to telehealth meeting - 1 day (3 days if Friday enrollment?)
time to receive medication - up to 3.5 days
Most results including the primary 28-day PCR+ result has not bee reported yet. The study uses a low and slow dosage regimen, therapeutic levels may only be reached nearer to day 14, if at all, so day 28 results should be more informative when available (although labeled a PEP trial, with the low dosage and continuous exposure for most participants it is more of a PrEP/PEP trial where benefit might be seen later as HC
Q levels increase).
PCR+ @28 days - NOT REPORTED YET
PCR+ @14 days - aHR 0.99 [0.64-1.52]
PCR+ symptomatic @28 days - NOT REPORTED YET
duration of shedding - NOT REPORTED YET
Not in study protocol:
PCR+ symptomatic @14 days - aHR 1.23 [0.76-1.99]
Dose in first 24 hours - 0.8g (compare with Boulware et al. 2g)
Dose in first 5 days - 1.6g (compare with Boulware et al. 3.8g)
Other research suggests vitamin C may be beneficial for COVID-19, e.g. . No information on severity is provided - binary PCR does not distinguish replication-competence. There were 2 COVID-19 hospitalizations but the group(s) have not been reported yet.
Side effects were similar for HC
Q and placebo. 84% medication adherence at day 14.