The COVID-19 epidemic looks increasingly likely to become a pandemic, but a number of biotech companies are racing to develop vaccines that can protect people against SARS-CoV-2, the coronavirus that causes it. One of these companies is Inovio Pharmaceuticals (INO 2.17%), which famously crafted its first vaccine candidate for the novel coronavirus in a mere three hours, at least according to CEO J. Joseph Kim. 

Shares of Inovio have been red hot over the past month or so, a stock performance that it can credit to investors' faith that one of its vaccines will prove effective against the rapidly spreading virus. However, not everyone believes that Inovio was able to create INO-4800 (its candidate vaccine) so rapidly. The well-known short-seller Citron Research recently tweeted that the claim that Inovio had produced INO-4800 in three hours "ludicrous and dangerous."

Citron Research then went even further, warning investors that the stock would fall back to $2, and called for the Securities and Exchange Commission to investigate Inovio and suspend trading of its stock. Inovio's shares plunged by more than 30% on the heels of Citron Research's tweet. However, even after that sharp decline, the company's shares are up by 140% year to date, which compares quite favorably to the S&P 500's 13.6% loss thus far in 2020. 

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Inovio responds to Cintron Research 

The biotech company sent out a tweet of its own to reassure investors, dismissing Citron Research as a third-party that had "demonstrated a lack of understanding of the science behind DNA medicines."  Inovio also reaffirmed its claim that it had created a potential vaccine for COVID-19 within three hours after the genetic sequence of SARS-CoV-2 was made public. Inovio says it still plans to start human clinical trials of INO-4800 in the U.S. in April.