Pfizer (NYSE:PFE) confirmed this week what everyone has been expecting. COVID-19 vaccine sales are falling drastically. The company reported a 77% drop in Comirnaty sales in the first quarter compared to the same time a year ago. As we head toward a post-pandemic world, demand won't equal that of a pandemic situation.

The big pharmaceutical company also sells coronavirus treatment, Paxlovid. And that product, too, is set to see declines. In fact, Pfizer expects Comirnaty and Paxlovid sales to fall 64% and 58%, respectively, this year. Considering this, should you still buy Pfizer shares? Let's find out.

The coronavirus portfolio

First, let's talk about the coronavirus portfolio. It's true that coronavirus products have driven growth at Pfizer over the past couple of years. But Pfizer was addressing a pandemic, which is an exceptional situation.

Pfizer calls 2023 a transition year for Comirnaty and Paxlovid. Vaccine makers will shift to selling their products directly to pharmacies instead of to governments. And people may begin to opt for annual coronavirus boosters. Pfizer expects vaccine demand to decline through next year then pick up as of 2025 if companies are able to launch combined coronavirus/flu shots. The idea is the population that generally goes for a flu shot would instead go for one of these combined products.

Last year, Pfizer even said it expects its coronavirus program to generate multibillion-dollar revenue for the "foreseeable future." Even with the sharp declines predicted this year, Comirnaty and Paxlovid together should bring in more than $20 billion. That's a significant level of revenue for two products.

And, if we start using this year or next year as a basis for comparison, we may see growth in coronavirus-product revenue over time.

All of this means the program still represents a valuable asset for Pfizer even if it won't bring in the same level of revenue we saw during the pandemic. At the same time, another positive point is Pfizer doesn't rely uniquely on its coronavirus program for revenue. The company has a full portfolio of products across treatment areas, and right now, it's in the middle of a major shift that should boost growth over the next few years and beyond.

Nineteen potential launches

Some of Pfizer's older products face patent expirations and therefore declining revenue. But Pfizer has been working on its pipeline and signing business deals that should more than compensate for revenue losses. Pfizer expects 19 potential launches over an 18-month period. That's a record for the pharma giant.

One big one ahead is the regulatory decision -- set for later this month -- on Pfizer's respiratory syncytial virus (RSV) vaccine candidate for older adults. This market is worth more than $10 billion, according to Moderna (a potential rival). But this market size leaves plenty of room for more than one player to succeed.

Plus, Pfizer is leading in the development of an RSV candidate for use in pregnant individuals to protect unborn babies through the age of six months. The U.S. Food and Drug Administration aims to decide on that indication in August.

Finally, Pfizer's business deals should also offer growth ahead. The company recently announced the acquisition of Seagen to boost its position in oncology. It says Seagen could deliver $10 billion in risk-adjusted revenue in 2030 and possibly "significant growth" beyond that.

Now, let's look at Pfizer's valuation. The stock trades for 11 times forward-earnings estimates, down from 15 earlier this year.

It's true Pfizer shares may not take off overnight. Investors may focus on the sluggishness of growth during this time of transition. But this is the perfect time to get in on the stock for a good price and benefit from passive income while you wait; Pfizer has increased its dividend for 14 years and makes dividend growth a priority. And down the road, you'll potentially see your investment gain ground as Pfizer's new products spark a new wave of growth.