In recent times, Moderna (MRNA -6.86%) shares haven't exactly been stock market superstars. The stock that climbed 1,200% over the past two years has lost a good deal of momentum. It's dropped 39% year to date. So, investors may be wondering what could offer shares of this coronavirus vaccine giant a boost.

The company reports earnings on May 4. Considering Moderna's $21 billion in advance purchase agreements for this year, we may expect another billion-dollar quarter. Could that sort of news boost the shares? For some clues, let's check out what Moderna shares did in the months following the past three earnings reports.

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Performance loses steam

Let's start with second-quarter 2021 earnings, reported back in August of last year. Moderna shares soared immediately following news of the company's billion-dollar revenue and profit. But the performance quickly lost steam. And, a month later, Moderna shares found themselves almost back at their pre-earnings-report level.

MRNA Chart

MRNA data by YCharts

Now, let's see what happened a few months later following the third-quarter earnings report. Here, investors were disappointed when Moderna revised its full-year revenue estimates lower. The shares fell in the days following the report, but they rebounded as investors digested the news -- and understood that the lower guidance actually was due to a timing issue. The company was favoring deliveries to lower income-countries first, and they pay less for vaccine doses.

MRNA Chart

MRNA data by YCharts

Finally, let's look at Moderna's share performance after the company's latest earnings report. This is the fourth-quarter and full-year 2021 report, announced in February of this year. In the chart below, you can see the shares initially declined. But in the month following the report, they climbed more than 15%.

MRNA Chart

MRNA data by YCharts

What does this say about share performance ahead?

So, what does this say about Moderna's potential share performance following the upcoming earnings report? In the past, Moderna has announced positive news: blockbuster earnings, increased vaccine orders, and advancement of candidates in the pipeline, for example. In the last two reports, though, this hasn't been enough to push the stock to huge immediate gains. And that may be the case when Moderna reports in May.

But this shouldn't discourage long-term investors. All of the positive news Moderna has been announcing in these recent earnings reports should help boost the stock down the road. Moderna's earnings today are helping it invest in its pipeline. These candidates are progressing -- and in the future, they may result in major revenue. And all of that should help Moderna's stock gain over time.