A bad seven-month stretch just got worse for Moderna (MRNA -1.96%). The messenger RNA (mRNA) pioneer provided a business and pipeline update at the J.P. Morgan Healthcare Conference on Monday. This update wasn't well-received by investors, and Moderna's share price sank nearly 17%.

The conventional investing wisdom is that you shouldn't "try to catch a falling knife." Moderna's stock chart certainly looks like a falling knife. Even before the latest decline, the biotech stock was down roughly 73% since early June 2024. But is Moderna stock instead a no-brainer buy on the sell-off?

How concerning is Moderna's latest bad news?

Let's first look at why investors were so unhappy with Moderna's business update. The company generated product sales of between $3 billion and $3.1 billion in 2024. That total is less than half of the $6.67 billion in net product sales reported in 2023, and is on the low end of Moderna's previous guidance range.

But investors were even more disappointed by Moderna's outlook for 2025. The company expects to deliver revenue of between $1.5 billion and $2.5 billion. The upper end of this range is well below the average analyst estimate of $2.92 billion compiled by LSEG. It's also lower than Moderna's previous forecast of 2025 revenue between $2.5 billion and $3 billion.

Moderna cut its guidance because there's a lot of uncertainty in the vaccine market. It acknowledged "additional competitive pressure in [the] COVID market" in the J.P. Morgan presentation, along with the potential for lower vaccination rates.

The company does have another product on the market now, respiratory syncytial virus (RSV) vaccine mResvia. However, it cited "uncertainty around ACIP [Advisory Committee on Immunization Practices] RSV revaccination and age group recommendations."

How concerning is Moderna's latest bad news? From a near-term perspective, I'd give it an eight on a scale of one to 10, with 10 being the most worrisome. Anyone who thought (as I did) that the worst was over for Moderna's COVID-19 vaccine sales will be especially bothered by the company's update.

More to the story

But while Moderna's near-term prospects don't look as good as many of us expected, there is more to the story. The mRNA innovator's long-term prospects still seem bright.

Moderna continues to project 10 product approvals over the next three years. It's already awaiting regulatory decisions on three: a next-generation COVID-19 vaccine, a combination influenza/COVID vaccine for adults ages 50 and over, and approval for mResvia in adults ages 18 to 59.

The company anticipates five approvals in 2026 and two in 2027. Together, these potential new products target a total addressable market of over $30 billion.

Meanwhile, Moderna is reducing expenses. It estimates cash costs of around $6.5 billion in 2024, and expects the total to fall to roughly $5.5 billion this year and $5 billion in 2026.

A no-brainer buy?

I've been bullish about Moderna over the long run, even viewing it as a possible five-bagger by 2030. The company's lower guidance has forced me to reevaluate my position.

If we assume Moderna only hits the low end of its 2025 revenue forecast, the stock trades at roughly 9 times forward sales. That's well above the 7.2 price-to-sales ratio for the biotech industry.

However, Moderna's enterprise value (EV) is $10.75 billion -- lower than its market cap thanks to a hefty cash stockpile and manageable debt load. If the company can generate $2 billion in sales this year (the midpoint of its guidance range), its stock will be trading at under 5.4 times its EV. I think that's an attractive valuation, considering Moderna's growth prospects.

Is Moderna a no-brainer buy on the sell-off? I wouldn't go that far. Investors should think long and hard about the company's challenges in the vaccine market, and the probability of success with its pipeline programs. However, I still view this beaten-down stock as a good pick for aggressive investors with a long-term horizon.