Worry over the growing spread of the novel coronavirus has sent shares of some of my favorite long-term healthcare stocks -- like leading telehealth provider Teladoc Health (NYSE: TDOC) -- skyrocketing in recent weeks against the cascade of red descending on stock markets. For investors, the hope is that a search for a vaccine and heightened demand for health services could help offset pain in other sectors. Picking stocks based on what is sure to be a transient disruptor of the economy is not the point of this article, though. Instead, these three healthcare stocks have my attention, two for their cheap valuation and one for its long-term potential: Amgen (NASDAQ: AMGN), AbbVie (NYSE: ABBV), and Veeva Systems (NYSE: VEEV). A pioneer of biotech still going strong Amgen has been around for decades now, but one of the largest pharmaceutical and biotech companies in the world still has a lot going for it. Its extensive portfolio of treatments covers everything from asthma and arthritis to cancer. Over 20 products are also undergoing phase 3 testing -- including psoriasis treatment Otezla for use in treating other inflammatory diseases, which it acquired in 2019. That drug is expected to drive renewed revenue growth in 2020. However, Amgen isn't without some imperfections. Biosimilar treatments have eroded the strength of its core portfolio of products, and a full-year 2019 revenue decline of 1.6% to $23.4 billion is proof of that. During that time, expenses were higher, offset by the company's share repurchase program (which reduces share count and thus increases earnings per share). As a result, earnings per share were still able to notch a 2.1% increase. A promised return to revenue growth in 2020 (at least 7% according to guidance) is nevertheless good news. But why buy this massive biotech stock now? Post-Q4 2019 earnings and coronavirus-fueled declines, Amgen is down nearly 15% from all-time highs on fear that pharmaceutical makers' access to ingredients may get disrupted due to manufacturing closures in China. As a result, Amgen stock trades for just 12.3 times one-year forward expected earnings. The drug developer also generated $8.5 billion in free cash flow (revenue less cash operating and capital expenses), giving it plenty of room to continue investing in new treatments, making acquisitions, and returning cash to shareholders. As to that last point, that is another reason to give the stock a look. Amgen is serious about increasing its cash payout (in addition to share repurchases) and has raised its dividend 84% since 2015. As of this writing, the biotech outfit yields 3% a year. With shares down double-digits on short-term worry and trading for a value, this looks like a good buy point for investors looking longer-term. Image source: Getty Images. An even steeper discount on big pharma Here's another timely buy for value-oriented investors: AbbVie, which expects its takeover of peer Allergan to be complete sometime during the first quarter of 2020. While that pending deal and AbbVie's patents on autoimmune disease treatment Humira expiring in the next few years (they already have expired in Europe) clouds the picture a bit, not to mention coronavirus-fueled selling like Amgen has been experiencing, quite a bit of uncertainty looks priced in. It's true that Humira still made up 58% of sales in 2019, in spite of losing a third of its sales internationally due to biosimilar competition. There will be further disruption in a few more years when the same happens to the treatment stateside. However, combining with Allergan will significantly diversify the product portfolio. Besides inorganic growth, though, AbbVie is also seeing great success with its oncology products, most notably with lymphatic cancer and leukemia treatment Imbruvica, which grew global sales by 30% last year. In total, AbbVie's full-year revenue grew just 1.6%, but it forecast an 8% increase in 2020 (excluding Allergan) over the $33.3 billion posted in 2019. Even better was expected adjusted earnings growth of 8% at the midpoint of guidance (again excluding Allergan). Shares are thus trading for only 9.6 times that new-year earnings guide. Much like peer Amgen, AbbVie is a cash cow. Free cash generation of $12.8 billion in 2019 means this biotech giant has plenty of wiggle room to keep investing and reward shareholders. Stock repurchases are ongoing, as is a current annual dividend yield of 5.1%. With patent expirations, merger worry, and global pandemic supply chain disruption keeping stock valuation low, AbbVie looks too cheap to ignore for investors looking for value and yield. A new digital toolkit for life sciences Let's go from value stock to growth stock. Veeva Systems is actually a software company, but with the purpose of helping modernize the life science industries -- biotech, pharmaceutical, and healthcare companies -- and more recently it announced it's making a push with its software into cosmetic and personal care products. Veeva is still getting north of 20% a year growth from its core competencies, but the new adjacent industry could provide an opportunity just as large as the first one. Through the first three quarters of 2019, Veeva's revenue is up 25%, and management has said to expect a full-year growth rate of 26% -- which would make it the first year Veeva crosses the $1 billion in revenue milestone. Even better than the top line, though, are high profit margins that are leading to even faster earnings growth. Adjusted earnings are up 41% through the first three quarters of 2019 and expected to finish the year up 33%. Veeva isn't a cheap stock; on the contrary, it's downright expensive when viewed purely in the context of profit generation. Shares trade for 56 times trailing one-year free cash flow and 49 times one-year forward earnings. It's all about the long-term future for this software outfit, though, and the company's steady addition of new revenue is leading to an increasingly efficient profit-generating machine. If the bottom line can continue to outpace the already-high rate of revenue growth, the premium on share prices isn't totally unreasonable. Of course, as I often suggest with growth stocks, it's advisable to start with a very small position (less than 1% of investable net worth) and buy more shares on the dips. And dip it has. Veeva is still off all-time highs set over the summer of 2019 by 15%, including a nearly 10% tumble since coronavirus fears have flared up. I'm a buyer ahead of the company's final 2019 report card due out on March 3. 10 stocks we like better than AbbVieWhen investing geniuses David and Tom Gardner have a stock tip, it can pay to listen. After all, the newsletter they have run for over a decade, Motley Fool Stock Advisor, has tripled the market.* David and Tom just revealed what they believe are the ten best stocks for investors to buy right now... and AbbVie wasn't one of them! That's right -- they think these 10 stocks are even better buys. See the 10 stocks *Stock Advisor returns as of December 1, 2019 Nicholas Rossolillo and his clients own shares of AbbVie and Teladoc Health. The Motley Fool owns shares of and recommends Teladoc Health and Veeva Systems. The Motley Fool has a disclosure policy.Source