What happened

Shares of Inovio Pharmaceuticals (INO -2.21%) closed up 18% on Wenesday after Jim Cramer gave the vaccine maker a shout-out on his Mad Money show yesterday. Fellow COVID-19 vaccine-maker Moderna Pharmaceuticals (MRNA 0.02%) closed up 4% on the day. https://www.thestreet.com/jim-cramer/oil-rout-spooks-stocks-cramers-mad-money-april-21

So what

Inovio is developing a COVID-19 vaccine called INO-4800 that entered a phase 1 clinical trial earlier this month. Data from Inovio's study is expected by late summer, so it isn't readily apparent why investors would be buying today other than Cramer's call-out. Moderna is a little ahead of Inovio, so it should have data before Inovio.

Inovio and Moderna were able to develop their vaccines quicker than the large pharmaceutical companies, such as Johnson & Johnson (JNJ -0.43%), which won't start a clinical trial until September, because their vaccines use patients' cells to express the protein vaccine, eliminating the need for developing a new manufacturing system like Johnson & Johnson. Inovio's vaccine uses DNA to express the protein, while Moderna's mRNA-1273 uses RNA.

Gloved hands about to give an injection into a shoulder

Image source: Getty Images.

Now what

At a market cap of $1.7 billion, Inovio isn't particularly expensive if the biotech is able to keep pace with Moderna and show that INO-4800 can induce an immune response.

But investors should keep in mind that investing in Inovio is still risky. There are no guarantees that the vaccine will create antibodies that protect patients. And estimating exactly how much of the vaccine Inovio will be able to sell is difficult without knowing the price, how much it'll be able to manufacture, and how much competition INO-4800 will have if regulators approve it.