All three major indexes dipped into bear market territory this year, and this left many stocks across many sectors in the doldrums. The S&P 500 Index and the Dow Jones Industrial Average have rebounded from lows, but some stocks haven't caught up. In fact, many are greatly underperforming the market.

Teladoc Health (TDOC 0.50%), Novavax (NVAX -4.32%), and Disney (DIS -0.12%) are good examples. They've lost 69%, 87%, and 39%, respectively, compared to a 16% decline for the S&P 500. Should we give up on these laggards or is now the time to buy? Let's take a closer look and find out.

1. Teladoc Health

Teladoc disappointed investors when it reported two billion-dollar, non-cash goodwill impairment charges earlier this year. This was linked to the purchase of chronic-care specialist, Livongo.

Investors already were worried about Teladoc's lack of profitability. So this news prompted many to turn their backs on the telemedicine leader.

But things are looking better for Teladoc. In the most recent quarter, the company didn't report further impairment charges. And it's important to remember that chronic care is a key growth area for Teladoc -- so the Livongo acquisition may pay off over time. Teladoc also narrowed its net loss in the recent quarter.

Another positive point: Teladoc continues to grow revenue and visits in the double digits each quarter. The company also has progressively increased U.S. member numbers and revenue per member. Teladoc serves more than half of Fortune 500 companies, so there are plenty of reasons to be positive about the future.

Trading at its lowest ever in relation to sales, Teladoc is a screaming buy right now.

TDOC PS Ratio Chart

TDOC PS Ratio data by YCharts.

2. Novavax

Novavax was one of the earlier hopefuls in the coronavirus vaccine race. The stocks soared more than 2,700% back in 2020 as investors bet on its vaccine program.

But manufacturing problems slowed things down, and Novavax's vaccine reached the market a full year after rivals in most countries. In the U.S., it only won authorization this summer.

As a result, Novavax missed out on the initial demand for coronavirus vaccinations. It's revised this-year's revenue forecasts lower, and it seems unlikely the company will carve out significant market share in the near term.

All of this sounds grim, but there are some bright spots that could boost Novavax over the long term. First, the vaccine, as Novavax's first commercialized product, is generating revenue. That eventually can support pipeline growth.

Second, Novavax is working on a combined flu/coronavirus vaccine candidate. It expects to start a phase 2 trial by the end of this year. A combined product could be big down the road.

Should you buy the stock? Not if you're a cautious investor. Even though a potential combined vaccine could make Novavax a long-term winner, the next few months may continue to be rough. It's best to keep this player on your watch list.

3. Disney

Entertainment-giant Disney is struggling with higher costs across its businesses. It's made enormous investments in its streaming services -- and that's resulted in membership growth. The membership trend is positive, but Disney still must get costs under control.

Enter longtime Chief Executive Officer Bob Iger. The company called him out of retirement to take the helm last month. He'll stay for two years and name a successor.

Can Iger put Disney on the right path? He has a track record of growing earnings and share price during his tenure at the company, so there's reason to be optimistic.

DIS Chart

DIS data by YCharts.

Another positive point is that Disney's parks, experiences, and products segment continues to post double-digit growth. In the recently ended fiscal year, that unit's revenue climbed 73%. This is important because the parks unit generally has contributed most to Disney's total revenue. Disney parks remain the most popular in the world.

Now let's look at valuation. Disney is trading at 22 times forward earnings estimates, which is down from more than 40 earlier this year. This looks like a great time to buy -- and bet on Disney's recovery and, possibly, a new era of growth.