Shares of Moderna (MRNA) are falling after the company said its newly approved RSV vaccine was only about 50% effective after 18 months.

Yahoo Finance's Anjalee Khemlani breaks down the efficacy of the vaccine and how it stacks up to similar vaccines from competitors GSK (GSK) and Pfizer (PFE).

For more expert insight and the latest market action, click here to watch this full episode of Market Domination Overtime.

This post was written by Melanie Riehl

Video Transcript

Well, one more here, Moderna That stock falling after the company said its newly approved RSV vaccine was only about 50% effective after 18 months, you find Angeli Klane following the story.

She joins us now for more.

This is RV was going to be a big deal for them.

It was maybe still will.

But this is a blow to it.

It could still be Well, we're seeing the stock down right now because investors are are looking at the Moderna drug compared to compared to Pfizer and those who also in the market in the same 60 older population.

And what we're seeing is that Moderna's efficacy after a longer period of time is much lower.

If you take a look at, uh, GSK, they have 60% and Pfizer at 77% over longer periods of time.

And this data came out in a in a CDC Advisors meeting that took place today, and they still voted unanimously to allow all three of these and to recommend rather, uh, all three of these vaccines on the market for one dose for those 16 older.

So that's going to be what the market looks like Now this is a $444 million opportunity for Moderna, according to J PM.

But as we know, uh, CEO Stefan Mansell has had his eye on the RSV market for a while, thinking about the broader opportunity.

Here's what he told us last month, anticipating the launch this spring.

If you look at analyst consensus, the market could be around $10 billion market.

So it's a big market.

It's bigger than the flu market of the do so, as you can see, you know, looking at that 10 billion as a potential.

What Moderna's actual take of this market will be will depend on whether or not those E numbers matter to the CDC who will make the ultimate decision as well as to providers.