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What works against COVID-19 — and what doesn't

Uta Steinwehr | Kathrin Wesolowski
January 20, 2021

A number of drugs have been mentioned as treatments for COVID-19. Some of them work well, some of them don't work at all, and some are still being tested.

Pile of colored medicinal pills and capsules
A number of drugs have been touted as helping combat COVID-19, but very few have been confirmed as effectiveImage: picture-alliance/Zoonar/R. Kneschke



As researchers sought treatments early in the pandemic, the Japanese drug Avigan, with the active ingredient favipiravir, was promoted within Asia and then worldwide. Used for severe strains of influenza, the drug has been found to be a potent inhibitor of many RNA viruses. The drug can shorten the time to recovery for patients with COVID-19 — but the possible side effects are severe, including anaphylactic shock and pneumonia.


The anti-inflammatory drug dexamethasone has been found to reduce the 28-day mortality in patients who are hospitalized with severe COVID-19. Germany's Robert Koch Institute (RKI) and the World Health Organization (WHO) recommend the use of the drug in such cases. 

Dexamethasone is not recommended for patients with mild symptoms, and it should not be used prematurely. "If you use it too early, you would dampen or block the immune system and could even provoke the disease to become more severe," Sandra Ciesek, director of the Institute of Medical Virology at the University Hospital Frankfurt, said in October in a podcast from the public broadcaster NDR.



At the outset of the pandemic, the active ingredient in the anti-malarial drug hydroxychloroquine was used on a limited basis. Several studies have found it to have severe side effects and to be an ineffective treatment for COVID-19.

Two malaria mosquitoes on human sking
Hydroxychloroquine has long been used to combat malaria but is not recommended as a remedy for COVID-19Image: H. Bellmann/F. Hecke/blickwinkel/picture alliance

Under study


No reliable clinical studies have produced results on the effects of artemisia, the active ingredient in wormwood, which was promoted early in the pandemic as a treatment in patients under the brand Covid Organics.

A team led by Peter Seeberger, the head of the Biomolecular Systems Division at the Max Planck Institute of Colloids and Interfaces, has established that extracts of the plant are effective against COVID-19 — at least in the test tube. The study has appeared as a preprint only and as not yet been finally peer-reviewed. A phase II study with 360 participants is currently underway in Mexico.

 Seeberger told DW that people should not drinking artemisia teas "in the belief that they prevent or cure COVID-19: At present there is no clinical evidence."

School students holding up bottles of Covid Organics in a classroom in Madagascar
Authorities in Madagascar distributed Covid Organics in schoolsImage: picture-alliance/dpa/L. Bezain

Tocilizumab and sarilumab 

The effectiveness of the anti-inflammatories tocilizumab and sarilumab is under review. The active ingredients are usually used to treat rheumatoid arthritis and, according to a recent preprint, could reduce mortality among COVID-19 patients in intensive care units. A study of 243 patients published in December, however, concluded that it did not significantly reduce intubation or death for patients with moderate COVID-19. The UK government plans to use the agents. 

Medical personnel in an ICU unit in Marseille, France
Researchers are looking for drugs that reduce the severity of COVID-19 and the need for hospitalizationImage: Theo Giacometti/Getty Images


The WHO and the US Food and Drug Administration advise against this anti-parasitic drug to treat COVID-19.

The US Frontline COVID-19 Critical Care Alliance, on the other hand, has evaluated clinical data and concluded that the drug could significantly reduce viral load and accelerate recovery in patients with mild and moderate cases. The drug is reported by the group to reduce the need for hospitalization and lower mortality.

Remdesivir — no evidence

US President Donald Trump was administered remdesivir while being treated for COVID-19, but the efficacy has not been proved. Within the European Union, it has been approved for conditional use in patients with COVID-19 pneumonia; in the United States, it is permitted for people who have been hospitalized. The WHO recommends against the use of remdesivir.

Donald Trump leaving the hospital and giving the thumbs-up
Remdesivir and dexamethasone were used to treat Donald Trump when he contracted COVID-19Image: Jonathan Ernst/Reuters

Unproven preventive

Mouthwash and nasal spray

The German Society for Hospital Hygiene (DGKH) recommends gargling with certain mouthwashes to kill viruses in the throat and temporarily reduce the risk of transmission by infected people.

British soldiers gargling in a bid to ward off the flu
Mouthwash, being used here by British soldiers in 1939 to try to ward off the flu, is an ages-old home remedy Image: Harry Shepherd/Fox Photos/Getty Images

"Of course, you don't reach the viruses as long as they are in the cells," DGKH spokesperson Peter Walger told DW. "So you're not eliminating the infection, but only eliminating the free viruses, which — if coughed up or exhaled — would be the basis for a new infection." 

It's a similar concept for antiviral nasal sprays. The product algovir has been under discussion. 

In a study by a research group in the German city of Bochum, scientists found that various mouthwashes reduced the amounts of coronavirus detected in test tubes. As of August, the WHO and German dental societies have recommended that patients gargle with mouthwash before treatment — even if there are no clinical studies proving that gargling and rinsing one's mouth is effective in preventing human-to-human transmission.

This article was adapted from German by Dagmar Breitenbach. 

What is remdesivir?