Why there is finally a smallpox drug, even if the disease does not exist anymore

This is an excerpt from Second Opinion, an eclectic and sub-radar weekly news bulletin on health and medical science sent to subscribers every Saturday morning.

If you're not a subscriber yet, you can do it by clicking here

For centuries, people have lived in fear of smallpox, a disease characterized by an eruption that is unclear. is transformed into pustules, especially on the face, arms and legs. If you were lucky, you would survive, but you would often have scars. Up to a third of the millions of infected people in the world have died.

Fortunately, it does not exist anymore. After a worldwide vaccination campaign, smallpox was declared eradicated in 1980.

So why did the US Food and Drug Administration announce its approval of tecoviramat (brand name TPOXX) – the first drug for this terrible disease?

defense against bioterrorism. In fact, the drug company's first client is the US government's Advanced Biomedical Research and Development Authority.

The manufacturer, SIGA Technologies, delivered two million courses (each consisting of two capsules per day for 14 days) from TPOXX to the US National Strategic Reserve – a vaccine and drug depot for use in the US 39, event of an epidemic of rare disease or biothreat.

The company would not tell CBC News the price per dose, but its initial contract with the government is worth 472 million US dollars, including drugs.

This actor was made to appear to have smallpox in the biocontainment unit of the Nebraska Medical Center in 2006. (Nati Harnik / Associated Press)

] At present, smallpox is only approved for sale to the US government, but SIGA has declared its intention "to explore additional markets and potential indications for TPOXX in the United States and around the world." "

One of those clients might be the Canadian government.

" I think this is a potential option for the future, "said Dr. Theresa Tam, the administrator Chief of Public Health of Canada

"Although we have a smallpox vaccine, we are following treatments such as TPOXX at developmental stage."

Synthetic Viruses

Canada has its own own national stock of vaccines and treatments "for things that are unlikely to occur, but [are] potentially high impact ", including smallpox, as well as Ebola and anthrax.

If the manufacturer went to the federal government, Canadian authorities would badess the scientific merit of the drug and weigh the risks and benefits before deciding whether to approve or purchase it. said Tam.

But if smallpox has been eradicated, how could it be used as a biological weapon?

Stocks of viruses still exist, kept in two secure laboratories – one in the United States and one in Russia – for research purposes. These places are regularly inspected by the World Health Organization (WHO).

Although there is no evidence of remnants elsewhere, it is possible that there are, said David Evans, a professor of virology at the University of California. # 39; Alberta. member of the WHO Advisory Committee on Smallpox. He is also a consultant for a competing company working on a different smallpox drug.

A big concern is the advent of synthetic viruses, Evans said. His own research has shown that it is possible to recreate the smallpox virus – which is in the same family as smallpox.

"This is not beyond the field of technically competent people to make the virus [smallpox]" Evans said. "It's not easy to do, it would take a very sophisticated lab to access technologies for synthesizing DNA."

This 1975 microscope image made available by the Centers for Disease Control and Prevention shows a group of variola virus. (Fred Murphy / CDC / Associated Press)

If anyone wanted to make a virus for bioterrorism purposes, there would be others that would be more infectious and simpler to manufacture than smallpox, he said.

But smallpox "unfortunately has some kind of cachet" and the threat of it would cause "total panic" because of its devastating history, Evans said. That's why governments want to have treatments in stock.

"It's insurance," he said.

So how does TPOXX work?

Smallpox is caused by variola virus. The drug blocks the release of the virus from the cells that it infects, containing it before it can spread anywhere else in the body, Evans said.

"So the drug prevents the disease from progressing but you still rely on an immune system to eliminate it."

WHO documents confirm that there are more drugs to treat smallpox. In 2016, Russia was developing one called NIOCH-14, and another US company reported progress on a drug called brincidofovir.

To read the full Second Opinion newsletter every Saturday morning, thank you for subscribing.