Last update and review: May 6, 2020.
Huang et al., 2020 (1), submitted a publication that describes the use of chloroquine phosphate in the treatment of COVID-19 patients in the Hubei and Guangdong provinces in China.
The most interesting detail is the following sentence. Huang et al., 2020 (1):
“The epidemic in Guangdong had been brought under control rapidly during the study making it difficult to recruit patients as planned.”
Indeed, there are doubts that China reports real data on the number of its COVID-19 cases. The sentence above from the study by Huang et al., 2020 (1), hints that China is telling the truth.
Regarding effectiveness of chloroquine phosphate for treatment of COVID-19, there results require additional analysis. On one hand, the authors found that chloroquine was effective at clearing viral RNA faster. On the other hand, the treatment with chloroquine started late in the course of the disease. That is, when the viral RNA is normally not found anymore in most of COVID-19 patients.
Huang et al., 2020 (1):
Eligible patients received chloroquine phosphate 500mg, orally, once (half 85 dose) or twice (full dose) daily. Patients treated with non-chloroquine therapy 86 were included as historical controls.
A total of 197 patients completed chloroquine treatment, and 176 patients were included as historical controls. The median time to achieve an undetectable viral RNA was shorter in chloroquine than in non-chloroquine (absolute difference in medians -6.0 days; 95% CI -6.0 to -4.0).
In the table below, you can see that chloroquine phosphate treatment started on average (mean) 7 days (Guangdong) and 19(!) days (Hubei) after the onset of symptoms.
Lescure et al., 2020 (2), published an informative study that described the first cases of COVID-19 in Europe. You can see in the figure below from their study that by day 10 since the onset of symptoms, the viral load was below the “quantification level” in the patients’ nasopharyngeal swabs, with the exception of the patient 3. Patient 3 was a man in his eighties who had a severer course of the disease and later died.
Huang et al., 2020 (1), write that they used “respiratory samples” but do not say exactly if they used nasopharyngeal swabs:
(The COVID-19 patients were) tested by the local Center for Disease Control (CDC) or by a 342 designated diagnostic laboratory, using reverse-transcriptase-polymerase- 343 chain-reaction (RT-PCR) assay (Shanghai ZJ Bio-Tech Co Ltd) for SARS- 344 CoV-2 in a respiratory tract sample.
The criteria of stopping chloroquine was defined as undetectable 356 viral RNA for two consecutive respiratory tract samples.
So, there remains uncertainty over the results and the meaning of the chloroquine study by Huang et al., 2020 (1), since the authors achieved undetectable viral RNA levels in patients who should not have had detectable RNA by the time the treatment started.
Selected references:
1. Huang (Mingxing) et al. Preliminary evidence from a multicenter prospective observational study of the safety and efficacy of chloroquine for the treatment of COVID-19. Pre-print. 2020.04.26.20081059; doi: https://doi.org/10.1101/2020.04.26.20081059
2. Lescure et al., Lancet Infect Dis, 2020. Published: March 27, 2020 DOI:https://doi.org/10.1016/S1473-3099(20)30200-0
1 Comment