There's been lots of excitement surrounding Novavax (NVAX -7.42%). The company beat earnings expectations for the first quarter as it has been slashing expenses, and recent clinical trials -- including those for its combination flu and COVID-19 vaccine -- have also been promising. The stock has been rising on these developments.

But before you rush out to add it to your portfolio, there are three numbers you need to look at first.

$625 million in cash

Cash burn is a big concern for a company such as Novavax, which is likely to see its revenue decline as demand for its COVID-19 vaccine dwindles. As of the end of March, the company had $625 million in cash and cash equivalents on the books -- down by more than half from more than $1.3 billion it reported at the end of 2022.

Source: Company filings. Chart by author.

It's especially problematic given that during the first three months of 2023, the company burned through $326 million just from its day-to-day operating activities. It's probable that Novavax will need to raise money through a debt sale or a secondary stock offering in the near future. The risk of dilution for existing shareholders can put pressure on an already-struggling stock -- shares of Novavax have fallen 84% over the past 12 months.

$81 million in Q1 revenue

Not only is demand low for Novavax's vaccine, but the company also had to record a revenue reversal due to doses it says were delivered last year but "that are scheduled for future replacement." For the full year, the company is projecting revenue of between $1.4 billion and $1.6 billion. That's down from the nearly $2 billion that the company reported in 2022. 

Source: Company filings. Chart by author.

But investors should take its guidance with a grain of salt. This is the same company that in 2022 cut its guidance in half. And earlier this year, management warned that it may even struggle to survive because of its dire situation. Even if revenue does bounce back, investors need to prepare for the reality that it will be much lower in future periods.

$394 million in Q1 operating expenses

Exacerbating those problems, Novavax's operating expenses remained high at $394 million last quarter. A quick look at the chart below shows why the company could be in trouble if it doesn't act fast to trim its costs.

Source: Company filings. Chart by author.

Novavax did announce this month that it would be laying off 25% of its workforce, but even that may not be enough to turn this into a sustainable business. A lot will depend on the level of revenue it can consistently generate, which at this point is unclear.

Investors should steer clear of Novavax

Novavax's pipeline isn't bare, but it's not terribly exciting, either. Assuming it earns regulatory approval, its vaccine for respiratory syncytial virus (RSV) will likely face competition from Moderna and Pfizer, which are both working on RSV vaccines of their own, and GSK recently obtained approval from the Food and Drug Administration for its shot.

And while Novavax does have a flu vaccine in the works as well, the global influenza vaccine market was worth just $7.28 billion in 2022, according to data from Grand View Research. And it won't be easy to win market share there, either.

Without a big catalyst or a product to get investors excited about the healthcare stock, it's little wonder Novavax's share price has been struggling. And based on its most recent results, there's no reason to expect things will really change. This is a stock that investors would be better off avoiding, as things could continue to get worse for the business.