The new coronavirus that has sickened more than 70,000 people in central China is spreading, setting off outbreaks in South Korea, Iran, and Italy, and now threatens to move around the globe as a true pandemic. The US Centers for Disease Control today said that its spread in the US is inevitable too, although how many people will get the disease is unknown.

“We are asking the American public to prepare for the expectation that this might be bad,” Nancy Messonnier, director of the National Center for Immunization and Respiratory Diseases, said today.

If the disease known as Covid-19 does become a pandemic, one thing is for sure: billions of people will be hoping for a drug or vaccine.

While there’s no proven treatment yet for the virus and the pneumonia it causes, there are more than 70 drugs or drug combinations potentially worth trying, according to the World Health Organization.

Here are some of the most promising, fast-moving research projects.

Virus blockers

Although experimental, the injectable drug remdesivir, made by Gilead Sciences, is a broad-spectrum antiviral that Francis Collins, head of the National Institutes of Health, says he’s “optimistic” about.

The drug forms a misshapen version of a nucleotide that the virus needs to build new copies of itself, thus preventing it from multiplying. The same type of strategy led to Gilead’s blockbuster hepatitis C drug.

Remdesivir is a good prospect because it’s broadly active against viruses whose genetic material is made of RNA, like the coronavirus. It works well in mice and monkeys infected with MERS (a related germ), although it didn’t help very much when it was given to Ebola victims in Congo starting in 2018.

In January, remdesivir was given to a 35-year-old man in Washington state who caught the coronavirus during a trip to China and who then recovered. To find out whether it really works, the NIH said today that it would run a study of remdesivir at the University of Nebraska Medical Center in Omaha, where some Americans with the disease are being cared for or are under quarantine.

According to the agency, the study will be blinded: some subjects will get the drug and others a dummy injection, or placebo. The first person to join the trial is an American who was on the Diamond Princess cruise ship, the site of a major outbreak.

Vaccines

Probably the best defense in the long term, a conventional vaccine has the drawback that such drugs usually take three or four years to reach the market, at the quickest. That’s because it takes time to prove they protect people from infection and manufacture them in large amounts. As well, it’s not unusual for vaccines to simply fail, sending scientists back to the drawing board.

Luckily, a bunch of prototype vaccines were developed against SARS, the coronavirus disease that killed 774 people starting in 2003. Though the vaccines were never needed after SARS stopped spreading, some of those approaches are being dusted off for the new virus.

One company developing a coronavirus vaccine is Sanofi. Its approach is to manufacture proteins called antigens from the virus; these can be injected into the bloodstream, training people’s immune system to recognized the germ. Usually that kind of vaccine is made in chicken eggs, but that’s a big bottleneck. Millions of eggs aren’t easy to come by. Sanofi has developed other ways to make antigens inside insect cells.

Faster vaccines

Some companies are experimenting with new types of vaccines that involve injecting short strands of genetic material from the virus directly into people’s bodies. That way, their own cells make the viral antigens. Although such vaccines haven’t had major success in medicine yet, they are among the quickest varieties to create prototypes of.

That became clear this week when one company, Moderna Therapeutics, said it had already shipped some doses of an RNA vaccine to the NIH. Those could be given to volunteers in a safety test starting as soon as April. “We have never rushed to intervene on a pandemic in this time frame before,” says Stephen Hoge, the company’s president.

Plasma from survivors  

A person who gets infected with a virus but beats it has blood swarming with antibodies to the germ. It’s been shown that collecting blood plasma from survivors and infusing it into another person can sometimes be life-saving. While plasma is not certain to work, more than 27,000 people are already listed as recovered from coronavirus in China, so there could be an ample number of donors. Doctors in Shanghai are among those trying plasma infusions.

HIV drugs

To help patients in severe respiratory distress from the virus, doctors in China are prioritizing drugs they can get hold of, and these include several medications already approved for HIV. One hospital in Shanghai, for instance, tested a combination of the pills lopinavir and ritonavir in 52 patients. The company AbbVie markets this combination as Kaletra in the US. While they didn’t see any effect, more studies are planned or under way using other drugs, including Descovy, a once-daily pill taken by people who don’t have HIV but are at risk for getting infected through sex.

Chloroquine

According to some social-media posts, the cure for coronavirus is already known, and it’s the old anti-malaria drug chloroquine. Actually, that’s not proven. But studies of the cheap, well studied, and readily available compound are under way in China, with patients getting 400 milligrams a day for five days. Initial laboratory tests suggest the drug, discovered in 1934, may be highly effective.

Correction 2/27/2020: Descovy is the trade name of the once-daily HIV prevention medication being tested in China, not Truvada.