Review on the global epidemiological situation and the efficacy of chloroquine and hydroxychloroquin

Review on the global epidemiological situation and the efficacy of chloroquine and hydroxychloroquine for the treatment of COVID-19


Covid-19 disease is caused by SARS-CoV-2, a virus belonging to the coronavirus family. Covid-19 is so new that there is currently no specific vaccine or treatment. Clinical trials are currently underway. In vitro tests are also being conducted to assess the efficacy of chloroquine and hydroxychloroquine for the treatment of this epidemic, which is considered a pandemic by the WHO. We note that the content of this review is dated. The information it contains is subject to change and modification as the epidemic progresses.


In mid-December 2019, in the city of Wuhan, in central China, an epidemic of coronavirus was declared. It is caused by a new type of coronavirus first named 2019-nCoV, then renamed SARS-CoV-2, never observed before its appearance in this metropolis of 11 million inhabitants.

Chinese health officials officially announced the discovery on 7th January, 2020. On 30th January, the World Health Organization (WHO) declared a public health emergency of international concern. On February 11, WHO gave a name to the disease caused by this new coronavirus: Covid-19. On 11th March, WHO upgraded the epidemic to a pandemic, the first triggered by a coronavirus [1,2].

On this subject which worries the whole world, several questions can arise on the coronavirus itself, the world epidemiological situation and the effectiveness of using chloroquine and hydroxychloroquine in the treatment. Answers to these questions will be found throughout this review.

What is a coronavirus? What is COVID-19?

Covid-19 disease, which appeared in China in late 2019, is caused by SARS-CoV-2, a virus that belongs to the great coronavirus. Very frequent, they can cause a simple cold as well as a serious respiratory infection such as pneumonia, causing fatal epidemics as it was the case with Sras or Mers and now with Covid-19 (for Coronavirus Disease) [1]. COVID-19 is the infectious disease caused by the last coronavirus that was discovered. This new virus and this disease were unknown before the outbreak appeared in Wuhan (China) in December 2019 [1]. Coronaviruses, which owe their name to the crown shape of the proteins that coat them, are part of a large family of viruses, some of which infect different animals, others humans. They are likely to cause a wide range of diseases. For humans, these diseases begin with a simple cold to a severe lung infection, responsible for acute respiratory distress [1].

What is the epidemiological situation of the coronavirus?

According to WHO, after an epidemic outbreak in China in January-February, the epidemic situation has changed globally since 23rd February, 2020. With the intensification of outbreaks in South Korea, Japan, and Singapore, and the appearance of new outbreaks in Iran and Italy. In these countries, we are witnessing community dissemination, with no identified link with cases imported from China. Two months after its appearance in China, the epidemic seems to have peaked there. In March 2020, the Chinese authorities announced that the number of new cases was declining sharply in the country. However, all the countries of the European Union are now affected by COVID-19 [1], especially Italy, Spain and France. On 16th March 2020, the WHO counted almost as many cases in China as outside of China: 165 515 confirmed cases worldwide, including 81 077 in China and 86 438 outside China (in 143 different countries). And 3218 deaths in China and 3388 outside China [3].

WHO has therefore called these countries to act for contain the coronavirus, which has killed more than 45 525 people and more than 896 450 cases of infection worldwide, according to data reported by the authorities on 2 April, 2020 [3].

The WHO Regional Director for Europe said the number of cases is expected to increase further. He urged countries to continue implementing a containment strategy while accelerating their efforts to fight the disease. It is essential to act quickly, and every day can make a difference [4]. Indeed, on 31st March 2020 Italy became at the top of the world ranking of deaths due to Covid-19, followed by Spain, but is just behind the United States in terms of cases tested positive for the virus. According to the newspaper, the world, in Africa, the sub-Saharan countries remain, until 28th March, still little affected by the Covid-19 in comparison with Europe, even if the number of cases increases rapidly. Indeed, the African countries multiply the measures much more precociously than Europe [5]. In the Maghreb, the States take early measures going from the simple prudence to the closing of the borders and confinement [5]. Indeed, the Situation on the scale reported by WHO (02 April, 2020) is shown in Table 1 and Fig. 1, Fig. 2 [3].

Review on the global epidemiological situation and the efficacy of chloroquine and hydroxychloroquin

Review on the global epidemiological situation and the efficacy of chloroquine and hydroxychloroquin

Fig. 1. Countries, territories or areas with reported confirmed cases of COVID-19, 02 April 2020 (WHO).

Review on the global epidemiological situation and the efficacy of chloroquine and hydroxychloroquin

Are there any drugs that can prevent or cure COVID-19?

The Center of Disease control (CDC), in a public document on its website published on 21st March 2020, informed that there are no US Food and Drug Administration (FDA)-approved drugs specifically for the treatment of patients with COVID-19. At present clinical management includes infection prevention and control measures and supportive care, including supplementary oxygen and mechanical ventilator support when indicated. An array of drugs approved for other indications as well as several investigational drugs are being studied in several hundred clinical trials that are underway across the globe [6]. Very recent studies have tested and shown the effectiveness and use of two drugs (chloroquine and hydroxychloroquine) for the treatment of COVID-19 disease. According to the US Centers for Disease Control and Prevention, hydroxychloroquine and chloroquine are oral prescription drugs that have been used for treatment of malaria and certain inflammatory conditions. Chloroquine has been used for malaria treatment and chemoprophylaxis, and hydroxychloroquine is used for treatment of rheumatoid arthritis, systemic lupus erythematosus and porphyria cutanea tarda. WHO includes it on its list of essential medicines, meaning it should be kept affordable and accessible at all times. Both drugs have in-vitro activity against SARS-CoV, SARS-CoV-2, and other coronaviruses, with hydroxychloroquine having relatively higher potency against SARS-CoV-2 [[7], [8], [9]]. Studies revealed that it has potential broad-spectrum antiviral activities by increasing endosomal pH required for virus/cell fusion, as well as interfering with the glycosylation of cellular receptors of SARS-CoV [6,10]. According to Colson et al., 2020 the activity of hydroxychloroquine on viruses is probably the same as that of chloroquine since the mechanism of action of these two molecules is identical, and hydroxychloroquine was prescribed for long periods, which would be therefore the first choice in the treatment of SARS-CoV-2. For optimal treatment, it may be necessary to administer a loading dose followed by a maintenance dose [8].

Conclusion hydroxychloroquine a steroid

Despite efforts in clinical trials to assess the efficacy of drugs, previously used in other diseases, for the treatment of COVID-19. However, given the current serious global epidemiological situation and given the urgent therapeutic need. It is interesting to do more research to find a specific vaccine or drug for this epidemic in order to manage this health crisis effectively, to limit the rapid spread and to save humanity.

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