Moderna and BioNTech plummet more than 15% following news of Merck's COVID-19 antiviral pill

• Moderna and BioNTech both fell more than 15% on Friday after Merck announced positive results for its antiviral COVID-19 pill.
• Merck's antiviral cut hospitalizations and deaths in half for those infected with COVID-19.
• The drug is another option to help curtail the pandemic as countries struggle to reach herd immunity via vaccinations.
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The success of Merck's COVID-19 antiviral pill came at the expense of vaccine makers on Friday, with shares of both Moderna and BioNTech plummeting as much as 16%.

Shares of Novavax, which is developing its own COVID-19 vaccine, plunged as much as 26% in Friday trades, while more established vaccine makers like Pfizer and Johnson & Johnson fell 3% and 2%, respectively.

Merck jumped as much as 12% on Friday after it said its antiviral pill, molnupiravir, reduced the risk of hospitalization and death by 50% for those infected with COVID-19. The pharma company ended its phase 3 trial early due to the positive results and will file for emergency use authorization with the FDA as soon as possible.

Former FDA commissioner Scott Gottlieb said Merck's drug results are a "game changer," as the five-day pill regimen posted solid results and will likely have an impressive safety profile.

"This is a phenomenal result. This is a profound game-changer that we have an oral pill that had this kind of effect on patients who are already symptomatic," Gottlieb told CNBC on Friday.

The antiviral drug could put a dent into the uptake of COVID-19 vaccines, as countries still struggle to reach herd immunity due to vaccine hesitancy among certain segments of the population.

Whereas many in America have been hesitant to take vaccines, those same people haven't been as hesitant to take anti-viral drug cocktails from companies like Regeneron. That bodes well for Merck's antiviral pill among those who are unvaccinated and contract the disease.

Shares of Regeneron and Gilead fell as much as 8% and 3% on Friday, as Merck's antiviral drug is seen as far superior to their experimental therapies being offered in the treatment of symptomatic COVID-19 patients.