Antibiotics are designed to prevent bacteria from reproducing, and most will not have an effect on viruses. That’s because bacteria are cells which can reproduce, while viruses are packages of genetic material which cannot reproduce until they get inside cells. The way viruses replicate is different from bacteria, so drugs need to work in different ways to affect them.

However, antibiotics may be used if someone gets a bacterial infection on top of a viral infection – for example, if bacteria invade the lungs and cause bacterial pneumonia when someone is already ill with coronavirus.

Because of the pressing need for effective treatments for COVID-19, researchers are considering whether drugs already used for other conditions might have an effect, and this includes some antibiotics.

For example, an antibiotic called azithromycin is being tested in combination with antimalarial drugs in COVID-19 patients. Until the results of these studies are available, we won’t know if these drugs also have anti-viral activity.


Where did the story come from?

The Mail Online reported that “a team of researchers at the Norwegian University of Science and Technology” had said that four antibiotics could “stop the virus” in laboratory tests. The study itself, however, reported that the drugs have not been directly tested against the virus that causes COVID-19.


What is the basis for the claim?

The research paper on which the Mail Online article is based is a review of 120 drugs which have been used in humans before, and which the researchers believe may be active against a range of viruses. The researchers say these drugs would be good places to start to look for a treatment for COVID-19.

The majority of the drugs discussed in the review are already used against viruses (antiviral drugs), while some have been used for other infectious diseases such as malaria. The researchers list what stage the research on each drug is at (with laboratory tests the earliest stage and large-scale trials in humans the final stage) and which viruses or groups of viruses the drug has been tested against.

The list includes four antibiotics – teicoplanin, oritavancin, dalbavancin and monensin. These have been used in laboratory tests against other coronaviruses, but not against the virus that causes COVID-19. None of them was reported to have been tested beyond basic laboratory tests. Another 41 drugs were also listed as having been tested against one or more coronaviruses.

It is not clear why these four drugs were picked up by the Mail article as being of particular interest. None of them is the priority drugs currently being tested in large-scale trials on patients with COVID-19. There are ongoing trials of another antibiotic called azithromycin, which is being tested in combination with antimalarial drugs.


What do trusted sources say?

The World Health Organization says: “Antibiotics do not work against viruses, only bacteria. The new coronavirus (2019-nCoV) is a virus and therefore antibiotics should not be used as a means of prevention or treatment.

It adds: “However, if you are hospitalised for the 2019-nCoV, you may receive antibiotics because bacterial co-infection is possible.”

Analysis by EIU Healthcare, supported by Reckitt Benckiser



  1. Andersen P et al. Discovery and development of safe-in-man broad-spectrum antiviral agents. International Journal of Infectious Diseases, 2020; 93, 268-276.

Reading list

  1. World Health Organization. Myth-busters: Are antibiotics effective in preventing and treating the new coronavirus?