COVID-19 isn't going anywhere, not anytime soon at least. For investors, that means it's time to adapt and invest based on strategies that may be successful amid the pandemic. By holding investments in your portfolio that are able to do well even during adverse conditions like those that exist today, you'll save yourself some stress and possibly even earn a good return along the way.

Below, I'll show you four different investing strategies, involving 3M (MMM 0.79%)Teladoc Health (TDOC 0.21%)Abbott Laboratories (ABT 0.04%), and Viemed Health (VMD 1.67%). These companies all sell products and services that are in high demand during the pandemic. Here's a closer look at the different approaches and why each stock could be an attractive buy right now.

1. 3M for its protective equipment

3M offers a wide variety of products, but one area that's likely to remain strong is protective equipment. Masks, respirators, protective equipment, and cleaning materials are just some examples of the different types of products that consumers and businesses will need during the COVID-19 pandemic. 

Mask showing map of the world.

Image source: Getty Images.

The company's most recent results, which 3M released on July 28 for the second quarter ending June 30, were a bit disappointing with sales of $7.2 billion declining 12.2% year over year. However, a big part of that is likely due to many businesses not operating during the period amid shutdowns, leading to less demand for building and other materials. Personal safety sales of $1.1 billion, however, rose by 19.4% year over year. In the third quarter, with cities no longer under lockdown and heavy restrictions, 3M may see a recovery in many areas of its business while demand for personal safety, cleaning, and other products is likely to continue increasing.

As businesses adapt to their new normals, they'll need the tools and safety equipment from a trusted brand like 3M to help keep their customers and workers safe. And that's why investing in 3M could be a good move to make today. The stock's down 5% this year and could be an underrated buy.

2. Teladoc Health for virtual care

Teladoc's been seeing a surge for its services during the pandemic. Its virtual doctor visits are popular, especially among patients who may not want to physically visit the doctor's office right now. On July 29, Teladoc reported strong second-quarter results for the period up to June 30, with sales rising by 85% year over year and the number of virtual visits tripling to 2.8 million.

And it's not just in areas where COVID-19 cases are soaring that demand is high. Teladoc's services are getting lots of attention in places where it's less of a concern. "In some states where the curve has flattened, we are still seeing twice as many patient visits as last year," says CEO Jason Gorevic. 

Investing in virtual care looks to be a good move right now, as many people are looking to minimize their movements and exposure to the coronavirus. That makes Teladoc's planned merger with Livongo, which the companies expect will close later this year, a great way for it to reach even more people, in particular patients with diabetes. The acquisition only makes Teladoc stronger, and an even better buy if you're looking to benefit from the surge in virtual care services.

3. Abbott Laboratories for testing

Another service that's in high demand right now is testing. And with Abbott Laboratories shipping out 13 million antibody tests, 6 million molecular lab tests, and 7 million rapid ID NOW tests throughout the country, it's fair to say this is likely going to be a strong growth area of Abbott's for a while. That's without even mentioning its latest test, BinaxNOW, which delivers results in 15 minutes and costs only $5.

The potential for a cheap and quick test is massive, which is why the U.S. government is looking to order at least 150 million of them. The U.S. Food and Drug Administration (FDA) granted emergency use approval for BinaxNOW on Aug. 26, permitting its use on patients who are experiencing COVID-19 symptoms if it's been no more than seven days since the symptoms started.

There's tremendous potential for testing, given the government's desire to resume some sort of normalcy in the economy while balancing safety. With a quick and inexpensive way to test for COVID-19, Abbott can help minimize the spread of the disease. It's a top stock for anyone looking to invest in companies that do coronavirus testing.

4. Viemed for ventilators

Viemed makes medical devices, including ventilators. On Aug. 4, it reported strong second-quarter sales of $42.9 million for the period ending June 30. That was a year-over-year increase of 111% that is primarily due to what management calls its "COVID-19 response sales." Viemed's been working with hospitals and state agencies to help provide the necessary equipment to help treat people with COVID-19. That includes not just ventilators, but also protective equipment, respiratory equipment, and other supplies. 

Viemed's pre-tax profit of $12.8 million in Q2 was 30% of total revenue, and it was nearly 10 times the $1.4 million that it earned in the prior-year period.

Unfortunately, the need for ventilators and respiratory-related items is likely going to continue as long as COVID-19 is hospitalizing people. Viemed's one of the better options out there if you want to invest in a company that makes ventilators.

Which stock is the best buy?

There are many good options to choose from here for healthcare investors. But before deciding which one is the best, let's take a look at how each stock is doing this year.

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Only 3M has underperformed the S&P 500 this year, while Teladoc's soaring far above the other stocks on this list. Ultimately, I give the edge to Abbott Laboratories today because of its relatively modest rise in price and also how important testing will be, even after concerns about COVID-19 subside. With the company making a big name for itself with respect to COVID-19 testing, it's sure to play a key role in the economy getting back to some sort of normal, which could lead to strong results in future quarters.