Cathie Wood is known for her success over the long term. That's why so many of us love to follow her lead. Her biggest fund, Ark Innovation ETF, has steadily outperformed the S&P 500 for the past five years, for example. The founder of Ark Invest is particularly on the lookout for innovation and staying power.

In Wood's most recent shopping spree, she bought up shares of two pandemic winners. But here's the best part: These companies are likely to continue to win post pandemic too. So should you follow this star investor into these investments? Let's look at these two companies that Wood loves -- and see whether they make good candidates to add to your portfolio right now.

An investor looks pensively at a computer screen.

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Pfizer

Pfizer (PFE -0.15%) has been a big pharmaceutical player for years. But only last year did it reach superstardom. The company and partner BioNTech became the first to win emergency authorization for a coronavirus vaccine. Even better, just this month, the duo scored the first full approval of their vaccine. Some predict the vaccine will be the best-selling pharmaceutical product ever. Pfizer estimates the vaccine will generate more than $33 billion in sales this year alone. Even after sharing vaccine profit with BioNTech, the product still represents a huge contributor to the Pizer story. The company expects vaccine sales to make up 42% of this year's revenue.

And another potential product may truly crown Pfizer as the world's leading coronavirus player. The company is working on a treatment candidate. Pfizer's coronavirus pill would be given for a few days after the first signs of illness. Pfizer has reported positive preclinical data and encouraging safety data from early clinical trials. The company started a phase 2/3 trial in July and expects to report data in the fourth quarter.

Experts predict coronavirus vaccination may be annual. So it's likely Pfizer will generate billions of dollars in revenue from the vaccine into the future -- even after the pandemic is over. If Pfizer's treatment candidate is successful, it could become another blockbuster product. Beyond the coronavirus market, the company sells other billion-dollar products such as oncology drug Ibrance and anticoagulant Eliquis.

Pfizer shares have lagged behind biotech vaccine players like BioNTech or rival Moderna.

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I don't expect Pfizer to replicate their performance. Pharmaceutical companies usually don't soar on good news or drop drastically on bad news. Their performance tends to be steadier than that of biotech players. But I do expect Pfizer's growing sales and strong profit to make it a stock that will increase over the long term.

Teladoc Health

Teladoc Health (TDOC 2.93%) offered exactly what the world needed during a pandemic: virtual medical visits. This way, patients could consult with doctors from their armchairs -- and avoid exposure to the coronavirus in a waiting room. And it also offered patients an option if their local doctor's office closed temporarily or reduced hours.

As a result, Teladoc's business surged. The company reported a 98% increase in revenue last year to more than $1 billion and a 156% increase in patient visits.

Now, hearing all of this, you might have one big worry: What will happen after the pandemic is over? We already have a major clue. And it signals good things ahead for Teladoc.

The pandemic continues -- but medical offices have reopened, and people have returned to their routines. And at the same time, Teladoc reported a triple-digit revenue increase in the quarter ended June 30. This is key because the year-earlier comparison period was during the worst of the pandemic. So it shows that even as it becomes easy to return to in-person medical visits, many patients still are opting for Teladoc. The company also lifted full-year revenue guidance.

Analysts predict that growth in telemedicine is here to stay. The global telemedicine market is expected to climb from $79 billion last year to more than $396 billion in 2027, according to Fortune Business Insights.

Teladoc made acquisitions last year to ensure a successful future. The company bought InTouch Health to work more closely with a broad range of hospitals and health systems. And Teladoc's purchase of Livongo added strengths in the management of chronic diseases. More than 20% of Teladoc's chronic care patients today are enrolled in multiple programs. That's up from 6% a year ago.

What about the stock price? Teladoc shares have dropped 27% this year. This is amid concern growth will stagnate post-pandemic. But, as I've mentioned, Teladoc has shown us evidence that isn't likely to happen.

So, should we follow Cathie Wood?

My answer is: yes. Pfizer's and Teladoc's revenue clearly will benefit during the pandemic. But revenue at both companies is on track to continue growing well beyond the crisis. That means long-term investors should see share price weakness today as a great opportunity. An opportunity to get in on companies that have proven themselves during the worst of times -- and are set to show their strengths in better times, too.