Freeze dried food canneries are reporting 6-8 week backlogs due to increased demand. But these are prepper products for long-term storage up to 30 years. Your needs may differ and what Costco sells -- Kirkland canned chicken/beef/fish/veggies, bottled water, etc. may be sufficient.
The 6 x 1 gallon Kirkland bottled water has 18 month best used by date, but when stored properly it still tastes fine after 3 years. Smaller bottled waters, when left in the garage for a year, may have that plastic taste. But you still need some smaller bottled water (or water bottles) in case if you need to leave the house.
Kirkland canned foods have 3-5 year best used by date, and may last longer when stored properly. They're fully cooked "wet" cans that are ready to eat in an emergency, and can be rotated through monthly usage & replaced with new cans. You should eat fresh (not canned) food where possible, but canned food (and highly processed foods) is OK couple times a week or in emergencies.
If you're on prescription medication, call your doctor and see if you can refill your meds early. As last resort you can ask to buy generics out of pocket. If the virus spreads, hospitals and pharmacies will be like petri dishes filled with wiggly stuff.
Also consider what happens if utilities are cut or interrupted. If something is wrong at the substation or pump goes down, who's going to fix it if utility workers are staying home or bugged out? Costco sells Kirkland and Duracell batteries in large packs with 10 year shelf life, so get some extra batteries for your torch/flashlight and battery powered lamps.
Check camping section at Walmart or sporting goods stores for a "honey bucket toilet seat" that fits over a bucket. This is an emergency toilet. Stock up on toilet paper and boxes of quality kitchen bags at Costco, the kitchen trash bags will fit the toilet bucket and are leak proof. Instead of buying expensive disposable bucket toilet bags, just use the kitchen trash bags and toss (to your trashcan outside) often. Because there is nothing covering the excretion inside the bag, it's best to tie and discard as soon as possible. You can use those extra boxes of kitchen trash bags for your trashcan anyway.
Visit your local hardware store and pick up couple buckets, work gloves, and a shovel if you don't already have one. If trash pickup service is stopped then you may have to bury waste. Back when people built privy/outhouse the minimum safe distance away from house is 50 ft, preferably 100+ ft. Most of us don't have yards that big, so look around your community for suitable locations along green belts and such. Make sure you label the locations for cleanup later.
Other sanitation items to buy at Costco include Kirkland Nitrile Exam Gloves (disposable), bleach, 70% alcohol (near pharmacy area, don't buy 91%), Hydrogen Peroxide, disposable plates and utensils (you might not have running water to do dishes), etc.
