Moderna

(WAND) - Moderna, which makes a two-dose COVID-19 vaccine, believes people will need a third booster dose before the winter. 

According to NBC New York, the company said Thursday it is at work on a single shot that would be an annual booster against the virus. It would also protect against the flu and RSV, a respiratory condition. 

At least 63 million Americans have received both doses of the Moderna vaccine.

An investor presentation said the company believes "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." 

The company claimed early-stage testing for the booster showed it was effective against variants, including the more contagious delta strain. 

With the delta variant continuing to spread in the United States and cases rising, the Centers for Disease Control and Prevention have recommended people wear masks indoors, regardless of their vaccination status. New infections have risen to 120,000 a day - about six times more than they were a month ago. 

The CDC said unvaccinated people are eight times more likely to get a delta variant infection and 25 times more likely to be killed by it.

While Moderna claims people will need a booster, it's unclear if those who had the Pfizer or Johnson & Johnson shots will need another dose for additional protection. Pfizer's CEO has said a booster would be needed, but according to federal officials, not enough evidence exists to say that it's warranted.  

In San Francisco, health officials are offering a "supplemental" Pfizer or Moderna vaccine dose to those who got the Johnson & Johnson vaccine.Â