Pfizer (PFE 0.12%) has been one of the pandemic's success stories. The company and its partner BioNTech were the first to bring a coronavirus vaccine to market. And last year, that vaccine generated more than $36 billion in sales.

Looking ahead, though, the picture for Pfizer's revenue isn't 100% positive. There's some good news -- the green flag. And there's some bad news -- the red flag. Which piece of news will be most important for Pfizer and its shareholders? Let's take a look at the following three charts.

A healthcare worker vaccinates an individual.

Image source: Getty Images.

The future of vaccine revenue

First, we'll take a look at the bad news. And that's the possibility that coronavirus vaccine revenue won't stay at today's levels forever. Our first chart shows Pfizer's coronavirus vaccine revenue already may start declining this year. This forecast is for a decrease to $29 billion.

This chart shows forecasts for coronavirus vaccine sales for 2022.

Image source: Statista.

That level doesn't represent a dramatic change. But the next chart might. It shows overall mRNA product revenue falling to $21 billion by 2024. This chart includes all companies selling mRNA products. At the moment, this means Pfizer and Moderna. But, by 2024, a few other players may come to market with these types of products. In any case, even if Pfizer and Moderna remained the only two in the mRNA market in 2024, both still would see a considerable drop in vaccine revenue.

This chart shows the trend for mRNA product revenue through the mid-2030s.

Image source: Statista.

Now, let's move on to some good news. And that's in the form of the following chart. It shows global spending on medicines has been and continues to be on the rise. In fact, spending is set to reach nearly $1.6 trillion by 2024.

This chart shows an increase in global spending on medicines over the years.

Image source: Statista.

Blockbusters and pipeline

Here's why this is positive for Pfizer. The COVID-19 vaccine has been a massive moneymaker for Pfizer -- but this big pharma company doesn't rely on this product alone. In fact, Pfizer sells seven other blockbuster drugs. Those are drugs that generate at least $1 billion annually. And Pfizer has what it takes to keep revenue going. It has 89 candidates in the pipeline. And 27 of those are in phase 3 studies. So, we might expect new revenue drivers down the road.

Which flag is most significant for Pfizer and its shareholders -- the red or the green? Considering Pfizer's portfolio of blockbusters and solid pipeline, I'll go with the green flag. Even if the coronavirus vaccine's revenue falls as much as some predict, it won't happen overnight. And Pfizer has plenty of other products to keep revenue growing. So, with or without the coronavirus vaccine selling at today's levels, this pharmaceutical company looks like it will have plenty of good days ahead.