The World Health Organization has declared monkeypox a public health emergency. Infections are rising rapidly, including in the U.S. The rapid spread of the virus has investors jumping on so-called monkeypox stocks. As with Covid-19, not all will be winners.

Monkeypox Solutions Are Built on Smallpox

The stocks that are jumping mainly offer anti-viral drugs or vaccines in use against smallpox.

$SIGA Technologies(SIGA.US)$ is up almost 23% thanks to TPOXX, an oral drug used to treat smallpox. The drug is not yet approved for monkeypox in the U.S., but has been approved in Europe. Its market capitalization early on July 25 was $1.1 billion.

$GeoVax Labs(GOVX.US)$ is a pre-revenue company with a market cap of just $13 million. The stock jumped by two-thirds overnight on hopes its Modified Vaccinia Ankara-Virus Like Particle (MVA) vaccine program can quickly yield a monkeypox vaccine.

Bavarian Nordic (OTCMKTS:BVNRY) said it won European approval to apply its IMVANEX vaccine, already used against smallpox, to monkeypox. It has a market cap of $3.4 billion on 2021 sales of about $1.9 billion.

$Chimerix(CMRX.US)$ makes Tembexa, a drug used to treat smallpox. The U.S. Food and Drug Administration (FDA) is pursuing an expanded protocol to test it against monkeypox. It has a market cap of $188 million but 2021 revenue of just under $2 million.

$Emergent BioSolutions(EBS.US)$ bought Tembexa from Chimerix in May, in an agreement that could include royalties. Emergent has a market cap of $1.66 billion on $1.8 billion of 2021 sales. Its product line already includes vaccines against anthrax and smallpox.

What Happens Now for Monkeypox Stocks?

The moves on all these companies are pure speculation, largely based on similarities between the smallpox virus and monkeypox. Whether vaccines and treatments for the former will work on the latter remains unclear.

How rapidly the story unfolds at the regulatory level will determine whether these companies go anywhere in the drug market, as opposed to the stock market. There could also be other companies in the mix, and the chances of a large drug company buying one of the monkeypox players can't be discounted.