Chloroquine and other drugs for COVID-19


This is not medical advice and I am not attempting to advise anyone on their health, so please don’t suggest that I am.  Please do not attempt to treat yourself without supervision by a qualified medical doctor.  

I have no medical qualifications whatsoever; I am a physicist, not a physician. I am however well accustomed to scientific research, sourcing and reading scientific papers, which I have done for over 40 years, and that includes biochemical and bio-medical ones. Having survived a non-Hodgkins lymphoma in 1996-7, owing my life to what was then a clinical trial protocol, I learned that when your life depends on it, previously obscure subjects like haematology and immunology can suddenly become very interesting. 

Medical professionals may find this summary and sources from the primary literature of interest, relevance, and – who knows – even of use. 

Political leaders should have their expert advisers evaluate the findings of these potential treatments for C19 infection. There is no time to lose.

Patients with symptoms of Covid-19 are encouraged to show these pages to their doctor. As I said at the top, there is no way I am qualified to recommend treatment for any individual.

Chloroquine and other drugs for COVID-19


A lot of excitement has been generated by news of a drug combination apparently successful at treating C19.  Chloroquine was trialled in the Chinese outbreak (reports mainly in Chinese with English abstracts), and taken up by President Trump announcing a formal clinical trial, whilst counterpoints from liberal media have been very keen to rubbish the possibility. Democratic state governors have even banned the use of the drug, and one even threatened to strike off doctors using it. 

Yet as of 30 March, the US FDA has announced an emergency approval, as has France. A limited clinical trial of the combination at a hospital in Marseilles has shown all patients on the combination cured after 6 days, compared with a control group who remained ill.  The Marseilles group have recently published a larger study of 80 without controls; the majority were cured; of nearly 2000 patients treated to date with the combination only 7 have died. The Marseilles group have now announced, citing their Hippocratic oath, that they will treat all patients with the combination, without control groups, as they are in the business of getting sick people better. They post a running total of patients treated on the protocol on their website. 

On March 31st Italian doctors announced that they were adopting the Marseilles protocol, and President Trump announced a million doses of chloroquine were being made available. 

Meanwhile, Prof Didier Raoult, the infectious diseases expert who is head of the Marseilles team, has once walked out of a French Government advisory committee and has latterly urged Africans not to accept Bill Gates’ claimed vaccine, asserting that chloroquine will be Africa’s salvation against Covid-19, not a vaccination.

The drugs involved

So what are the drugs and what is going on ?

Chloroquine (phosphate), one brand name Nivaquine, is a very old anti-malarial drug used since the 1930’s, now de-emphasised for malaria because of resistant strains, but remaining in use for many other purposes e.g. rheumatoid arthritis, polio, HIV and systemic lupus erythamatosus (aka "lupus" or SLE). It is a derivative of quinine, a natural product, before WWII the standard treatment for malaria and still used in tonic water as a flavouring. 

Having been used for decades, its tolerance and contra-indications are well known and in many parts of the world it is still routinely available, especially where malaria remains endemic, without prescription. (France only required a prescription from January his year). A strip of 5 tablets can be bought in India for Rs12 i.e. about 1.5p. There is absolutely no money in it for Big Pharma. 

It tastes unbelievably bitter (I was allowed a small shot of sherry as a child when taking it as a malaria prophylactic), overdoses will risk liver damage and it can change heart rhythms, but it did what it said in the packet, i.e. prevent, and treat, malaria. 

The relative hydroxychloroquine (sulphate) (typical brand Plaquenil) is newer and better tolerated; likely to be the drug of choice if it is truly successful for Covid-19. 

Shorthands for these notes: HCQ for hydroxychloroquine (as sulphate), CQ for chloroquine (as phosphate).

Azithromycin (shorthand AZM, typical brand name Zithromax or Z-pak) is an antibiotic similarly well-established for infections like traveler's “runs” and chlamydia. It also has known anti-viral action against larger viruses such as Ebola and Zika. Given to patients in Marseilles with the intention of preventing bacterial “super-infection” i.e. infection “on top of” the C19, they conjectured a synergistic effect with chloroquine against C19; in their first clinical trial, some but not all patients were cleared of the virus with HCQ alone; all were cleared with the combination. 

Also long-established, with tolerance and contra-indications well-known; it is obtainable by mail-order subject to consent from a GP.

Zinc (as a simple chemical compound) is also of relevance, is a component of the Marseilles protocol; and is widely available as a “nutraceutical” or “health food supplement”. You can get zinc gluconate tablets from Holland and Barrett, and it is added to some Vitamin C supplements available at retail outlets.

The excitement over these drugs is that they already exist. Their tolerances and contra-indications are very well-known. The only question is if they are effective against Covid-19 infections, and in particular if the HCQ+AZM combination is yet more so. The Marseilles group clearly have had significant success, are now using it routinely, as are doctors in New York state; the US FDA and French authorities have now issued emergency licensing for their use in Covid-19 and evidence is mounting from doctors across the world, when confronted with the necessity of "battlefield medicine", that the combination is effective, particularly when taken early in the infection (a recent report from Brazil says Days 2-4 of symptoms)

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Chloroquine for the 2019 novel coronavirus SARS-CoV-2

Enter Prof Didier Raoult in Marseilles: “re-purposing” existing drugs

The Marseilles team of Prof Didier Raoult noted chloroquine as a potential broad-spectrum antiviral, of negligible cost, and extremely well-known tolerance in a short Letter on 11 February with a terse summary of the possible modes of action.

1-s2.0-S0924857920300662-main.pdf Chloroquine for the 2019 novel coronavirus SARS-CoV-2 Philippe Colson et al. International Journal of Antimicrobial Agents 55 (2020) 105923

11 February 2020


Prof Didier Raoult in Marseille

Enter Prof Didier Raoult in Marseille

 The Marseille team of Prof Didier Raoult noted chloroquine as a potential broad-spectrum antiviral, of negligible cost, and extremely well-known tolerance in a short Letter on 11 February with a terse summary of the possible modes of action.

Prof Raoult is founder and director of l'Institut Hospital-Universitaire Mediterannee Infection (IHI-MI) and one of the world's leading experts in infectious diseases - some sites rate the "World #1" based on research publications. 

He is an advocate of "drug repurposing" i.e. finding new uses for established medicines, which are well out of patent (so no profit motive for anyone), cheap, and with established safety and tolerance. This certainly applies to chloroquine, which has been known since 1934, and has negligible cost anywhere.

This letter proposed the use of CQ and HCQ against the SARS-CoV-2 virus.

Primary source


Chloroquine for the 2019 novel coronavirus SARS-CoV-2 

Philippe Colson et al. (2020) International Journal of Antimicrobial Agents 55 (2020) 105923 


11 February 2020


The Breakthrough paper

So much for lab work: What about clinical treatments ?

This paper is rightly called a "Breakthrough". 

Cited by the Marseilles group on 11 February when available as pre-publication e-print; 

not actually published until 19 February 2020.  

From Chinese scientists at Qingdao. Multi-centre clinical trials in China were showed success against controls in treating COVID-19 pneumonia, in a group of over 100 patients.

Primary source


Breakthrough: Chloroquine phosphate has shown apparent efficacy in treatment of COVID-19 associated pneumonia in clinical studies 

Jianjun Gao et al. (2020) BioScience Trends. 14(1):72-73 Feb 19 2020

Breakthrough: Chloroquine phosphate has shown apparent efficacy in treatment of COVID-19

So much for lab studies “in vitro”: what about clinical treatments “in vivo”?


Chinese clinical trials show success against COVID-19 with chloroquine

The Marseilles group on 11 February cite a “breakthrough” paper not actually published until 19 February but available as an e-print beforehand, from Chinese scientists at Qingdao. Multi-centre clinical trials in China were showed success against controls in treating COVID-19 pneumonia in a group of over 100 patients.

14_2020.01047.pdf Breakthrough: Chloroquine phosphate has shown apparent efficacy in treatment of COVID-19 associated pneumonia in clinical studies Jianjun Gao et al.  BioScience Trends. 2020; 14(1):72-73 Feb 19 2020


all the known Sources on chloroquine against sars-COV-2 in v

Chloroquine known to work in vitro; just shown to work in vivo

By 14 March, the Marseilles group had tabulated the principal studies on the effectiveness of chloroquine against coronaviruses in vitro; and cited the Qingdao clinical trial paper (11 or 19 February), and noted from their own experience that effective concentrations of CQ could be reached with clinically tolerable doses.

Primary source

1-s2.0-S0924857920300820-main.pdf Chloroquine and hydroxychloroquine as available weapons to fight COVID-19 

Philippe Colson et al. (2020)  International Journal of Antimicrobial Agents xxx (xxxx) xxx 



The First Marseille clinical trial

16 March: IHU-MI release first trial results; discovery of a synergistic effect with Azithromycin

The major advance in a clinical trial came with a study published on 16 March:

This paper compared three groups of patients (i) an untreated control group (16) (ii) a group treated with HCQ alone (14) (iii) a third group treated with HCQ plus azithromycin (AZM) (6 patients). Whilst a small patient number (36 patients) and not a randomized or double-blinded trial, the results were dramatic; after 6 days only 2/16 patients in the control group showed no remaining virus; 8/14 (57%) treated with HCQ were clear of virus by Day 6, and in the combination treatment group 6/6 (100%) were cured after 6 days. 

Figure 2 (is the graph above) 

Percentage of patients with PCR-positive nasopharyngeal samples from inclusion to day6 post-inclusion in COVID-19 patients treated with hydroxychloroquine only, in COVID-19 patients treated with hydroxychloroquine and azithomycin combination, and in COVID-19 control patients.

The addition of azithromycin was made to control bacterial “super-infection” (ie bacterial infection on top of the Covid-19 disease) but from these results the Marseilles group conjectured a synergistic effect of the two drugs in combination. 

AZM had been demonstrated as effective against Zika virus by the Marseilles group, and against Ebola by others. Its established use to treat chlamydia is likewise action against an obligate parasite (chlamydia trachomatis) that has to invade a host cell in order to reproduce. 

Anti-viral action is therefore not unexpected although it was not the principal reason for inclusion. (Again, statements on the lines of "this is an antibiotic, and cannot be expected to be effective against viruses", are wide of the mark).

Their summary:

We therefore recommend that COVID-19 patients be treated with hydroxychloroquine and azithromycin to cure their infection and to limit the transmission of the virus to other people in order to curb the spread of COVID-19 in the world. Further works are also warranted to determine if these compounds could be useful as chemoprophylaxis to prevent the transmission of the virus, especially for healthcare workers.

A video announcing the results was also released:

Primary source


Hydroxychloroquine and azithromycin as a treatment of

COVID‐19: results of an open‐label non‐randomized clinical trial. 

Gautret et al. (2020) 

International Journal of Antimicrobial Agents 

17 March 2020 DOI:10.1016/j.ijantimicag.2020.105949

PUBLIC health administrators in the USA take notice

The Economic Standard

Opinion piece 24 March by Dr Jeff Colyer


By 24 March, American public heath administrators were taking notice, including Dr Jeff Colyer who is National Chairman of the Advisory Commission on Rural Health, and former governor of Kansas.

Click image for the article: "Combo of existing drugs shows promise against COVID-19" 

Use this treatment cocktail early, and don’t wait until a patient is on a ventilator in the intensive-care unit.” 

They also note that in some places hydroxychloroquine is being used as a prophylactic treatment for health workers in high exposure situations.

Key takeaway: Our experience suggests that hydroxychloroquine, with or without a Z-Pak, should be a first-line treatment. Unfortunately, there is already a shortage of hydroxychloroquine. The federal government should immediately contract with generic manufacturers to ramp up production. Any stockpiles should be released.

Zheijiang pilot study

Detail your services

In the US, this triggered critiques such as the following, cited 25 March:

with link to a small Chinese study 10.378_j.issn.1008-9292.2020.03.03.pdf A pilot study of hydroxychloroquine in treatment of patients with common coronavirus disease-19 (COVID-19) CHEN Jun et 13 alia (note appears to be error in printed doi reference) DOI : 10.3785/j.issn.1008-9292.2020.03.03 J. Zheijiang University, March 2020.

(Please see figure on left)


where patients treated with HCQ were mainly clear of virus after treatment – but so were the o-called “control” group. More careful study however shows that the other patients received “standard” Chinese protocol anti-viral drugs and therefore did not constitute a proper control group.



27 March: a larger trial study from Marseille

Released on Twitter on 27 March, results showed  93% patients no longer contagious after 8 days; 97.5% of those tested had no virus cultured from lung samples after 5 days.

Figure 1 (above). SARS-CoV-2 PCR from nasopharyngeal samples overtime. Black bars: number of patients with available results, grey bars: number of patients with PCR Ct value <34, solid line: percentage of patients with PCR Ct value <34, dashed line: polynomial regression curve.


Given the urgent therapeutic need to manage this disease with effective and safe drugs and given the negligible cost of both hydroxychloroquine and azithromycin, we believe that other teams should urgently evaluate this therapeutic strategy both to avoid the spread of the disease and to treat patients before severe irreversible respiratory complications take hold

Primary source


Clinical and microbiological effect of a combination of hydroxychloroquine and azithromycin in 80 COVID-19 patients with at least a six-day follow up: an observational study P. Gautret et 27 alia