Telehealth's moment has arrived at long last. The idea of visiting healthcare professionals from the convenience of your home isn't new. But virtual visits have skyrocketed in 2020 due to the COVID-19 pandemic.

As a result, Teladoc Health (NYSE:TDOC) has been a big winner for investors. Shares of the leading telehealth services provider have soared by more than 130% so far this year to an all-time high. And that was after a 69% gain in 2019.

A recent McKinsey & Company survey found that 76% of consumers who have used telehealth services say they would be likely to do so again. McKinsey projects that the telehealth market could reach $250 billion.

With all of this good news, you might think that Teladoc's continued business and share price growth is unstoppable. But if anything can derail Teladoc, I think there's one company with by far the best shot at doing it. 

Woman holding a smartphone with a physician appearing on the screen

Image source: Getty Images.

Lots of contenders

Teladoc isn't the only company in the telehealth market. There are quite a few contenders. 

One of the best-known rivals to Teladoc is AmWell, formerly known as American Well. The Boston-based company is reportedly planning to conduct an initial public offering later this year. Several big-name players in the healthcare sector have already invested in it, including health insurer Anthem and Japanese drugmaker Takeda Pharmaceutical

Doctor on Demand is another telehealth services provider that's on the move. Its Synapse product won "Best Telehealth Platform" honors at the 2019 MedTech Breakthrough Awards. Doctor on Demand has partnered with Walmart to offer virtual-care services to the retail giant's associates. It also teamed up with Humana to provide telehealth services to the health insurer's members.

Some companies in adjacent markets are also getting into the act. Zocdoc is a start-up that has a platform for booking medical appointments. It expanded into telehealth in April. Only seven days after the launch of its new service, Zocdoc had booked more than 350,000 telehealth appointments.

These three contenders are just the tip of the iceberg. There are hundreds of mainly small companies involved in some aspect of the telehealth market. 

An 800-pound gorilla waiting in the wings

My view is that Teladoc Health's momentum probably won't be impacted by any of its smaller rivals. It's not that several of them won't be successful; they will. However, there is an 800-pound gorilla waiting in the wings that just might be able to disrupt Teladoc's ascent. That gorilla is named Amazon (NASDAQ:AMZN).

It's no secret that the tech powerhouse is eyeing the healthcare market. Its most publicized steps into healthcare have been in the pharmacy arena. But the e-commerce leader has also quietly dipped its toes into the waters of telehealth.

In September, Amazon began offering telehealth services to its Seattle-based employees. The Amazon Care service includes video visits with healthcare professionals similar to those provided by Teladoc. So far, this telehealth offering is only available to Amazon employees and their families in the Seattle area. There are hints, though, that it could at some point be offered to Amazon employees elsewhere.

Don't be surprised if Amazon eventually markets its Amazon Care telehealth product to other employers. The company has taken a similar approach in other areas. Its super-lucrative Amazon Web Services business started out with the company's internally focused cloud hosting. Amazon initially developed its cashier-less store technology for its Amazon Go convenience and grocery stores, but it's now talking with other major retailers about licensing the technology.

Should Teladoc be worried?

I don't think that Teladoc Health should be too worried about the threat from Amazon yet. Over the longer term, though, it's very possible that Amazon will emerge as a formidable rival in the telehealth market and in the healthcare sector in general.

The good news for Teladoc is that it has a huge head start. The scope of services it offers and its geographic footprint are unparalleled in its niche. Teladoc claims 40% of the Fortune 500 in its customer base. It ranked No. 1 in J.D. Power's 2019 Telehealth Satisfaction Study. And the company is likely to continue acquiring smaller telehealth providers.

These advantages make Teladoc a clear leader in the telehealth market. My Motley Fool colleague Will Healy even views Teladoc as "the Amazon of online healthcare." I think Will is right -- at least for now. However, I wouldn't discount Amazon's ability to gain traction in the telehealth market. A decade from now, the "Amazon of online healthcare" just might be Amazon itself.