Because the coronavirus responsible for the Covid-19 pandemic is new to humans, doctors had no specific medicines to treat it at the start of the crisis. A scramble to fill that void is beginning to pay off, with the first medication backed by early clinical data authorized to fight the virus. Efforts will continue to ensure it works, find better treatments, and develop a vaccine that would prevent coronavirus infection to start with. In normal times, the process of approving new drugs and vaccines is slow and painstaking. It can be accelerated in times of crisis such as these, but at the risk of doing more harm than good.

1. What’s the proven treatment?

In late April, researchers announced that remdesivir, an experimental antiviral drug that Gilead Sciences Inc. originally made as a treatment for Ebola, helped patients recover from Covid-19 more quickly than standard care. Days later, it was cleared by the U.S. Food and Drug Administration for emergency use in Covid-19 patients. The authorization was limited to hospitalized Covid-19 patients with low blood-oxygen levels or who need breathing support. Japanese regulators authorized use of the drug based on the FDA’s approval.

2. Is there anything else?

The FDA in March controversially issued an Emergency Use Authorization providing for two malaria drugs, chloroquine and hydroxychloroquine, to be distributed and prescribed by doctors to Covid-19 patients. The move came after President Donald Trump repeatedly touted the drugs. Such authorizations are permitted during a crisis when a product’s “known and potential benefits” outweigh its “known and potential risks.” The Russian government in mid-April ordered the free distribution of hydroxychloroquine, which hadn’t been registered for use in the country previously, for treatment of coronavirus.

3. Why the controversy?

The FDA’s decision and Trump’s championing of the drugs have been criticized by scientists as premature. In a small study in France, hydroxychloroquine showed promising results, but the trial’s methodology has been challenged, and in another small trial in China, the drug was no more effective than conventional care. In another study published May 7, it failed to help those with infections stay off ventilators or live longer. And it carries significant side effects. In April, France reported 43 cases of heart incidents linked to treating coronavirus patients with hydroxychloroquine. Plus panic-buying of hydroxychloroquine has created shortages of the drug for patients with malaria and the autoimmune disease lupus, for whom it is a proven therapy. Larger trials of chloroquine and hydroxychloroquine are underway.

4. How do scientists prove a treatment is effective?

Even if a treatment shows promise in laboratory, animal or early human experiments, rigorous testing is needed to prove that it’s both safe and effective. That requires carefully structured and monitored tests known as clinical trials. Typically, these studies are designed to show that patients randomly assigned to get the drug do better than those in a “control group” who don’t, and that the results aren’t a product of chance. The trials try to subtract all the other influences and factors that might disguise the true effectiveness of the drug. For one thing, patients often recover from viral illness on their own, or improve because of supportive care such as rest and hydration. And some really sick patients might not respond to treatment no matter how effective it is. Treatments that don’t have approval from regulators should be viewed with extreme caution. The FDA and the U.S. Federal Trade Commission have warned multiple companies to stop selling unproven treatments for coronavirus.

5. How long does it take to prove efficacy?

It depends. Drugs that are already approved against one infection and shown to be safe can be tested for effectiveness against another in a matter of months. Experimental drugs may take longer to test, as they have to go through initial studies to evaluate whether they are safe. Other factors that can slow the process include the supply of drug candidates and the availability of patients to test them in. The trials also have to be approved by ethics watchdogs and drug regulators. According to a 2017 review, the median time for regulators to approve a new drug in 2015 was 333 days in the U.S., 422 days in Europe, and 639 days in China. China has since expedited its process. When drugs are deemed to fill an immediate need, regulators can speed them through the approval process using a number of paths.

6. What other treatments are being tested against Covid-19?

More than 100 different programs have been launched to develop and test treatments. These include everything from antiviral drugs and antibody-containing plasma from recovered patients, to traditional Chinese herbal medicine. A number of studies are looking at whether drugs for rheumatoid arthritis, cancer and autoimmune disorders can halt dangerous inflammation, sometimes called “cytokine storm,” which can be lethal. In a study in China published March 18, AbbVie Inc.’s Kaletra, an HIV treatment combining two drugs, failed to improve the condition of coronavirus patients. Another small, preliminary trial of the flu medication favipiravir, or Avigan, made by Fujifilm Holdings Corp. produced more promising results.

7. What about vaccines?

More than 70 experimental vaccines against the coronavirus are in some stage of development, according to the World Health Organization. Moving at record speed, researchers began preliminary human testing of the first one in mid-March in the Seattle area. It was developed by the U.S. National Institute of Allergy and Infectious Diseases in collaboration with the biotechnology company Moderna Inc. Since then, a handful of additional human trials have begun of vaccine candidates, including from CanSino Biologics Inc. and the Beijing Institute of Biotechnology and from Inovio Pharmaceuticals Inc. Some of the world’s biggest companies are working on vaccine projects. GlaxoSmithKline has teamed up with China-based Clover Biopharmaceuticals, while Sanofi and Johnson & Johnson are in separate collaborations with the U.S. government’s Biomedical Advanced Research and Development Authority. Widespread testing of experimental vaccines is important to reduce the possibility that they cause harm after being rolled out, as has been the case a number of times in the past. Documented reports of unexpected side effects from new vaccines are different from the persistent and incorrect belief that vaccines against childhood diseases carry significant risks.

8. How soon might there be a vaccine?

Anthony Fauci, director of the U.S. National Institute of Allergy and Infectious Diseases, said that it would take about a year and a half to complete trials of experimental coronavirus vaccines, scale up production and make a licensed product widely available. A team at the University of Oxford has set an ambitious aim of producing efficacy results for its vaccine candidate in September and aims to shorten the path to delivering the initial doses of a proven product by beginning manufacturing now. There’s no guarantee trials will yield a successful vaccine, however. The experimental products moving most rapidly are made using new technologies that have never proven useful in humans. SARS killed nearly 800 people in a 2002-2003 outbreak, and there still isn’t an approved vaccine. In a project that could deliver a vaccine sooner, researchers in four countries will test a shot that’s already licensed to prevent tuberculosis to see if it will protect health workers against the coronavirus.

For more articles like this, please visit us at bloomberg.com

©2020 Bloomberg L.P.