A drug used to treat people with HIV, the virus that causes Aids, is being trialled in patients in China as a possible therapy against the coronavirus.

News that HIV drugs are being deployed in hospitals, however, has led to panic buying on the black market by people who fear they are ill or are going to get sick. They have been obtaining the drug, Kaletra, from generics companies in India and even from people with HIV in China willing to sell or donate their own stocks.

Kaletra, a combination of two anti-HIV drugs, lopinavir and ritonavir, has been used on patients in a trial in China since 18 January. The aim is to test it in about 200 patients, whose condition will be carefully monitored. Their outcomes will be compared with those of similar people with the same degree of illness who have not been given the drug.

There are no proven treatments for the new coronavirus, nor the others that caused the earlier outbreaks of Sars (severe acute respiratory syndrome) in 2002 and Mers (Middle East respiratory syndrome) in 2012. There are still cases of Mers. In Saudi Arabia, where they are largely concentrated, there is already a trial of Kaletra, combined with another drug, interferon, but because of the small number of Mers cases it will take a long time to come to conclusions.

Quick Guide What are coronavirus symptoms and should I go to a doctor? Show What is Covid-19? Covid-19 is caused by a member of the coronavirus family that has never been encountered before. Like other coronaviruses, it has come from animals. The World Health Organization (WHO) has declared it a pandemic. What are the symptoms this coronavirus causes? According to the WHO, the most common symptoms of Covid-19 are fever, tiredness and a dry cough. Some patients may also have a runny nose, sore throat, nasal congestion and aches and pains or diarrhoea. Some people report losing their sense of taste and/or smell. About 80% of people who get Covid-19 experience a mild case – about as serious as a regular cold – and recover without needing any special treatment. About one in six people, the WHO says, become seriously ill. The elderly and people with underlying medical problems like high blood pressure, heart problems or diabetes, or chronic respiratory conditions, are at a greater risk of serious illness from Covid-19. In the UK, the National health Service (NHS) has identified the specific symptoms to look for as experiencing either: a high temperature - you feel hot to touch on your chest or back

a new continuous cough - this means you’ve started coughing repeatedly As this is viral pneumonia, antibiotics are of no use. The antiviral drugs we have against flu will not work, and there is currently no vaccine. Recovery depends on the strength of the immune system. Should I go to the doctor if I have a cough? Medical advice varies around the world - with many countries imposing travel bans and lockdowns to try and prevent the spread of the virus. In many place people are being told to stay at home rather than visit a doctor of hospital in person. Check with your local authorities. In the UK, NHS advice is that anyone with symptoms should stay at home for at least 7 days. If you live with other people, they should stay at home for at least 14 days, to avoid spreading the infection outside the home.

Gilead, a company that makes HIV drugs, has announced it will trial its drug remdesivir in the coronavirus outbreak. The drug was tested during the Ebola outbreak in the Democratic Republic of Congo in 2018, but the Congolese authorities announced it was not sufficiently effective against the virus.

The new trial of remdesivir will be gold standard, investigating how well it works in both moderately and severely ill patients compared with others given a placebo.

Peter Horby, professor of emerging infectious diseases and global health at Oxford University, said it was impossible to predict whether any of the drugs would be effective against the coronavirus.

“Nobody honestly knows. Most drugs that go into trials prove to be not effective. It is the more common outcome. One should be very cautious,” said Horby, who pioneered drug trials in the massive Ebola outbreak in west Africa.

If drugs are not given under strict trial conditions, he said, “we end up where we were after the 2009 [influenza] pandemic.” More than 40,000 people were treated for influenza by doctors with experimental drugs, mostly oseltamivir, better known as Tamiflu, which is licensed for seasonal flu but not for use in an epidemic. The crucial data on their condition and the difference the drugs made compared with other drugs or no drugs was not collected.

“People gave it [Tamiflu] because they thought there was no harm, said Horby. “You end up with large numbers of people being treated without the evidence you could have got. Trials are absolutely critical or you end up in limbo. The Chinese are really taking that on board.” They could have some answers within three or four months, he said.

But fear of the coronavirus has prompted many people to seek their own supplies of Kaletra, also known as Aluvia, which is drug company AbbVie’s off-patent version of lopinavir/ritonavir and the only one approved for sale in China – even though there is no evidence at the moment that it can help treat those who fall sick.

HIV patients have been offering their pills on Chinese social network Weibo.

“We felt like we were organised for a military mission,” said one of them, Andy Li, who has the nickname Brother Squirrel because he hoards stocks of his drugs. Hundreds of messages flooded in when they offered the pills, leaving him barely any time to sleep or eat in the first three days, he said.

“There are so many people in need of the drug, and I don’t want to waste time,” Li told Reuters. “Time is life.”

Others have seen a money-making opportunity, and have been buying stocks from India. Gatsby Fang, a Chinese cross-border buying agent, said he sold each bottle for 600 yuan (£66) each, earning 200-300 yuan in profit on each. His stock was sold out within two days. Some clients ordered 600 tablets at once, he said.

Until the trial results are in, most patients will receive supportive care in hospital, which means fluids and support for their breathing, if they need it, and for other organs if they begin to falter. Most healthy people’s immune systems fight off the virus and they recover.

Meanwhile, UNAids, the Joint United Nations Programme on HIV and Aids, says it is important that people with HIV continue to take their own medication and do not take risks by giving or selling their tablets to other people.

“UNAids stresses the importance of people on HIV treatment adhering to treatment and for access to adequate supplies of antiretroviral medicines to continue without interruption. People living with HIV must not be put under any pressure to go without or give up their medication,” it said in a statement.