Moderna says third dose likely necessary this fall as antibody levels wane and impact vaccine's efficacy

Drugmaker Moderna says a third dose of its COVID-19 vaccine will "likely to be necessary this fall." The pharmaceutical and biotechnology company believes a booster shot will likely be necessary because the spread of the Delta variant and vaccine efficacy could be diminished since antibody levels were expected to wane.

"We believe that increased force of infection resulting from Delta, non-pharmaceutical intervention (NPI) fatigue, and seasonal effects (moving indoors) will lead to an increase of breakthrough infections in vaccinated individuals," Moderna said on Thursday. "While we see durable Phase 3 efficacy through 6 months, we expect neutralizing titers will continue to wane and eventually impact vaccine efficacy."

The vaccine maker noted, "Given this intersection, we believe dose 3 booster will likely be necessary prior to the winter season."

Moderna CEO Stéphane Bancel told Fox Business the company is "waiting for a bit more data," but the COVID-19 booster shot could be available "as soon as September" for elderly populations who received the COVID-19 vaccine in January and February.

"And so it's important that people who are vaccinated a long time ago, especially with vaccines that have had lower efficacy, be protected so they are not hospitalized this fall and winter," he told host Maria Bartiromo on Thursday.

On Wednesday, the World Health Organization implored wealthy nations to hold off on the coronavirus booster shots because of vaccine inequity.

"We need an urgent reversal from the majority of vaccines going to high-income countries, to the majority going to low income countries," WHO Director General Tedros Adhanom Ghebreyesus said at a press briefing.

Moderna claimed a study found its COVID-19 vaccine to be 93.2% effective against the coronavirus six months after the second dose, 98.2% effective against severe coronavirus maladies, and 100% effective in stopping death caused by COVID-19. The biotech company also boasted that its COVID-19 offers "effectiveness against variants of concern (VOCs), including Alpha, Beta/Gamma and Delta, even after partial vaccination."

"We are pleased that our COVID-19 vaccine is showing durable efficacy of 93% through six months, but recognize that the Delta variant is a significant new threat so we must remain vigilant," Bancel told CNBC on Thursday.

Moderna expects to manufacture between 800 million to 1 billion COVID-19 vaccine doses in 2021 worldwide, and forecasts to supply up to 3 billion doses in 2022.

The United States has administered over 348.1 million doses of COVID-19 vaccines as of Wednesday, Reuters reported. Broken down by manufacturer, there have been 195 million coronavirus vaccine doses from Pfizer-BioNTech administered, almost 140 million from Moderna, and more than 13 million from Johnson & Johnson, according to CDC data.

The COVID-19 vaccine announcements were made on Thursday during Moderna's second-quarter earnings presentation. Moderna boasted about second-quarter revenue of $4.4 billion, $4.2 billion of which came from COVID-19 vaccine sales, according to the financial announcement. Moderna said it had generated $4 billion of cash in the second quarter, and held a total of $12.2 billion in cash and investments.

Despite the notable financial news, Moderna shares fell 2.4% in the premarket.

Last month, Pfizer announced that it enjoyed second-quarter revenues of $7.8 billion, half of which came from its COVID-19 vaccine developed with Germany's BioNTech. Pfizer expects to generate $33.5 billion in COVID-19 sales in 2021.

During Thursday's presentation, Moderna also announced that it is working on mRNA-1010, a quadrivalent seasonal flu vaccine. The pharmaceutical company said the mRNA flu vaccine was entering Phase 2 trials, and is currently looking for trial participants in the U.S. and Puerto Rico.

Moderna is also working on mRNA-1345m, a vaccine for Respiratory syncytial virus (RSV), a "common respiratory virus that usually causes mild, cold-like symptoms," but can be "serious, especially for infants and older adults."