What happened

Shares of Inovio Pharmaceuticals (NASDAQ:INO) were sinking 12.8% lower as of 3:27 p.m. EDT on Wednesday. The decline appeared to be caused primarily by two factors.

Inovio's shares slipped earlier in the day following comments that Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases (NIAID), made in an interview with JAMA editor Howard Bauchner. Fauci stated that he was concerned that COVID-19 vaccines likely won't provide a long period of immunity.

The stock fell harder later in the day, though, after The New York Times reported that the Trump administration selected five COVID-19 vaccines as the most likely to be successful. Inovio didn't make the cut.

So what

Fauci's remarks caused the stocks of several companies that are developing COVID-19 vaccines to tumble early on Wednesday. He stated that the durability of immunity with types of coronaviruses other than SARS-CoV-2 (the coronavirus that causes COVID-19) ranges from three to six months and is "almost always less than a year."

Gloved hand holding COVID-19 vaccine syringe

Image source: Getty Images.

The bigger story, though, was that Inovio wasn't in the group of five COVID-19 vaccine candidates that are reportedly on the Trump administration's list. The vaccine candidates that did make the top five, according to the New York Times report, were ones being developed by AstraZeneca (NYSE:AZN) and the University of Oxford, Johnson & Johnson (NYSE:JNJ), Merck (NYSE:MRK), Moderna (NASDAQ:MRNA), and Pfizer (NYSE:PFE) and BioNTech (NASDAQ:BNTX).

Inovio is currently evaluating COVID-19 vaccine candidate INO-4800 in a phase 1 clinical study. The company's preclinical data for INO-4800 demonstrated the production of what Inovio referred to as "robust neutralizing antibodies and T cell response" against SARS-CoV-2. 

Now what

Inovio expects to report results from its phase 1 study of INO-4800 in June. The company hopes to begin a phase 2/3 clinical study in July or August pending FDA approval. In the meantime, it's likely that the biotech stock will remain highly volatile with big swings on positive and negative news related to the development of COVID-19 vaccines.