Commentary
On 31 December 2019, the Chinese health authorities declared an outbreak
of a novel coronavirus (COVID19), which rapidly extended to many
countries. Last 11th of March 2020, the World Health
organization (WHO), after reported outbreaks in more than 110 countries,
declared COVID-19 as a pandemic [1].
Currently, vaccines and antivirals for COVID-19 are being investigated
around the world [2]. Several reports claimed the chloroquine
phosphate (chloroquine) could be an effective treatment for patients
with COVID-19, by inhibiting viral entry into the host cells [3].
The aim of this meta-analysis is to investigate the effectiveness of
chloroquine in treating coronavirus, in general not only COVID-19, by
pooling the results of randomized controlled clinical trials (RCTs).
A comprehensive PubMed search (from July 1966 until 15 March 2020) was
conducted using a variety of Medical Subjects Headings and free text
words: coronavirus AND chloroquine AND/OR clinical
trials . Additional searches were conducted in Cochrane Central Register
of Controlled Trials, Trip Database, Science Direct, and previously
published reviews. No attempts were made to locate any unpublished
studies. On the basis of the inclusion criteria, 28 publications were
identified. A copy of each paper identified was obtained, and relevant
data were abstracted.
The identified 28 publications none of which was a RCT. Identified
studies were published between 1987 and 2020.
Of these 28 publications, 7 were published from January 1, 2020 till
March 15, 2020 and discussed the effectiveness of chloroquine against
COVID-19 [4-10]:
- Multicenter clinical trials currently conducted in China with only
promising results that chloroquine could be effective for treating
COVID-19 (2 publications).
- Expert consensus on usage of chloroquine for treating COVID-19
associated pneumonia (1 publication).
- Reviews and recommendations in light to old experiments (2
publications).
- In vitro experiments, with one comparing chloroquine with
hydroxychloroquine (2 publications).
Table 1 summarizes the types of studies and the results of each.
Till March 15, 2020, the final results of the clinical trials currently
conducted in China were not available; only the preliminary results
reported promising effectiveness of chloroquine against COVID-19
[11].
The other 21 publications not related to COVID-19 were distributed as
follow; in vitro experiments (11 publications), in vivo experiments (5
publications), both in vitro and in vitro experiments (1 publication),
and reviews (4 publications). Only 2 in vitro experiments were about
Middle East Respiratory Syndrome coronavirus (MERS-CoV) and 5
publications (2 in vitro experiments, 2 reviews, and 1 in vivo
experiment) were about Severe Acute Respiratory Syndrome coronavirus
(SARS-CoV).
In conclusion, this meta-analysis could not prove that chloroquine is an
effective treatment against coronavirus in general or COVID-19 in
particular. Expanded access trials should be encouraged especially that
chloroquine is available, cheap and relatively safe drug.