There are many different ways you can diversify your investments. You can invest in different industries and in different parts of the world to try and bring down your overall risk. However, given the unpredictability of the coronavirus pandemic, it's clear that it may also be a good idea to ensure you have exposure to both the best and worst situations that could come about due to COVID-19.

Two types of stocks that may be useful to hold right now are stay-at-home investments that will do well if conditions deteriorate and there are lockdowns in the near future, and also those stocks that will do well under a best-case scenario in which the economy is fully up and running. Here are some of the best growth stocks to hold in either situation.

Young student wearing a mask.

Image source: Getty Images.

Stocks that could do well if COVID-19 case numbers continue climbing

Many businesses have done well during the pandemic and could get a boost if people need to spend more time at home. While it's not an ideal situation for the economy, it's a scenario that investors may want to prepare for.

Testing company Fulgent Genetics (FLGT 1.10%) could see a spike in demand for its COVID-19 tests should the delta variant keep case numbers rising and raise concerns about reopenings. Fulgent is coming off of a record-breaking 2020 in which its sales topped $422 million -- nearly 13 times the $33 million it posted a year earlier. Although the business is still expecting strong numbers in 2021, projecting growth of 90% for the full year, there will be some uncertainty ahead; demand for COVID-19 tests will undoubtedly play a huge role in how it does in 2021.

Zoom Video Communications (ZM 0.98%) is another example of a company that will likely do well in the event of heightened restrictions. While many businesses may be comfortable with doing more Zoom meetings this year, there will also be a significant number of workers who are eager to travel again and see colleagues in person. For the fiscal year ending Jan. 31, Zoom's revenue of $2.7 billion was more than four times the $623 million it reported in fiscal 2020.

The company is looking beyond the pandemic, however; one example is its recent acquisition of cloud contact center Five9 for $14.7 billion. The move will further expand Zoom's services and help it diversify its offerings, paving the way for some growth even after COVID-19. While Zoom may still generate strong growth numbers even after the pandemic is no longer a concern for investors, there's no doubt that if there are renewed stay-at-home orders and businesses will again be relying on Zoom for conference calls, the stock could be a hot buy.

Stocks to buy if you're hopeful of an economic recovery

If you are a glass-half-full type of person or just want to make sure you don't miss the opportunity to cash in on stocks that could surge in the wake of an economic recovery, there are a couple of great investments to buy for that purpose as well.

Restaurant Brands International (QSR 1.35%) owns top fast-food chains Burger King, Tim Hortons, and Popeyes. A year ago, the company struggled amid shutdowns, with systemwide sales (revenue from all stores) down 20.9% from the prior-year period. Fast-forward to now, and the company has generated systemwide sales growth of 31.9%, more than reversing the decline in revenue last year. (Compared with 2019, revenue was up by a more modest 5.5%.) Restaurants are hopeful that pent-up demand this year could make up for a difficult 2020, when the pandemic led many businesses to close for good. The National Restaurant Industry expects foodservice sales to rise 11% this year (they declined 24% in 2020).

Another good buy as things get back to normal is AmerisourceBergen (COR 0.42%). As physicians and hospitals resume normal operations, the medical distribution company will benefit.

While there was some initial stockpiling of pharmaceuticals during the early stages of the pandemic, COVID-19 disrupted the industry as a whole and caused significant variability for companies like AmerisourceBergen. Last year, during the period ended June 30, revenue was flat for the business.

However, a recovery already looks to be under way. For the same period this year, sales of $53.4 billion grew 18% from the prior-year period. Although these numbers were boosted by the company's acquisition of pharmaceutical wholesale Alliance Healthcare (which is still partly owned by pharmacy retailer Walgreens Boots Alliance), resulting in revenue from AmerisourceBergen's "other" segment rising by 128%, its pharmaceutical division also generated strong year-over-year growth of 13%.

With a return to normal healthcare treatments and regular patient visits to the doctor's office, AmerisourceBergen could continue to see some improved growth numbers this year, making it an attractive buy for an economic recovery.