As the new human coronavirus spreads around the world, individuals and families should prepare—but are we? The Centers for Disease Control has already said that it expects community transmission in the United States, and asked families to be ready for the possibility of a “significant disruption to our lives.”

Be ready? But how? It seems to me that some people may be holding back from preparing because of their understandable dislike of associating such preparation with doomsday or “prepper” subcultures. Another possibility is that people may have learned that for many people the disease is mild, which is certainly true, so they don’t think it’s a big risk to them. Also, many doomsday scenarios advise extensive preparation for increasingly outlandish scenarios, and this may seem daunting and pointless (and it is). Others may not feel like contributing to a panic or appearing to be selfish.

Forget all that. Preparing for the almost inevitable global spread of this virus, now dubbed COVID-19, is one of the most pro-social, altruistic things you can do in response to potential disruptions of this kind.

We should prepare, not because we may feel personally at risk, but so that we can help lessen the risk for everyone. We should prepare not because we are facing a doomsday scenario out of our control, but because we can alter every aspect of this risk we face as a society.

That’s right, you should prepare because your neighbors need you to prepare—especially your elderly neighbors, your neighbors who work at hospitals, your neighbors with chronic illnesses, and your neighbors who may not have the means or the time to prepare because of lack of resources or time.

Prepper and survivalist subcultures are often associated with doomsday scenarios and extreme steps: people stocking and hoarding supplies, building bunkers and preparing to go off the grid so that they may survive some untold catastrophe, brandishing weapons to guard their compound while their less prepared neighbors perish. All this appears both extreme and selfish, and, to be honest, a little nutty—just check the title of the TV series devoted to the subculture: Doomsday Preppers, implying, well, a doomsday and the few prepared individuals surviving in a war-of-all-against-all world.

It also feels like a scam: there is no shortage of snake oil sellers who hope stoking such fears will make people buy more supplies: years’ worth of ready-to-eat meals, bunker materials and a lot more stuff in various shades of camo. (The more camo the more doomsday feels, I guess!)

The reality is that there is little point “preparing“ for the most catastrophic scenarios some of these people envision. As a species, we live and die by our social world and our extensive infrastructure—and there is no predicting what anybody needs in the face of total catastrophe.

In contrast, the real crisis scenarios we’re likely to encounter require cooperation and, crucially, “flattening the curve” of the crisis exactly so the more vulnerable can fare better, so that our infrastructure will be less stressed at any one time.

What does “flattening the curve” mean for the current COVID-19 threat facing us: the emerging pandemic of this human coronavirus? Epidemiologists often talk about two important numbers: R0 or how infectious a disease might be, expressed as the number of people that are infected by each person who’s been infected; and the case fatality ratio (CFR): the number of people who die as a result of being infected. For example, an R0 of two means each infected person infects two people on average, while a number less than one means the disease is likely dying out in the population. Some diseases are deadlier than others: the average case fatality ratio for Ebola has been around 50 percent, for example, while the common cold is rarely deadly for otherwise healthy individuals.

But here’s the thing. Such epidemiological numbers are not fixed or immutable. They are not constants that exist independent of our actions. Where they land depends on the characteristics of the pathogen but also our response. By preparing now, we can alter both of those key numbers and save many lives.

The infectiousness of a virus, for example, depends on how much we encounter one another; how well we quarantine individuals who are ill; how often we wash our hands; whether those treating the ill have proper protective equipment; how healthy we are to begin with—and such factors are all under our control. After active measures were implemented, the R0 for the 2003 SARS epidemic, for example, went from around three, meaning each person infected three others, to 0.04. It was our response to SARS in 2003 that made sure the disease died out from earth, with less than a thousand victims globally.

Similarly, how many people die of seasonal influenza (or COVID-19) depends on the kind of health care they receive. In China, death rates are much higher in the overwhelmed Hubei province than the rest of the country exactly because of the quality of the care. Hospitals only have so many beds, especially in their intensive care units, and those who have a severe case of COVID-19 often need mechanical ventilation and other intensive care procedures. When they are out of beds, people end up languishing at home and suffering and dying in much larger numbers.

All this means that if we can slow the transmission of the disease—flatten its curve—there will be many lives saved even if the same number of people eventually get sick, because everyone won’t show up at the hospital all at once. Plus, if we can flatten that curve, there is more time to develop a vaccine or find antivirals that help.

There are now COVID-19 cases around the world, and epidemiological data from tens of thousands of cases. Here’s what we know: no doubt to the relief of parents everywhere, this disease is mild to nonexistent in children. There are almost no pediatric deaths and very few kids even seem to fall sick (though children may still be having clinically barely detectable cases, thus infecting others).

On the other hand, for the elderly or for people who have other diseases or comorbidities, it’s very serious, with death rates reaching up to 15 percent. It’s also a great threat to health workers who handle people with the virus every day, with thousands of cases already. Overall, it appears to have a case fatality rate around 2 percent, which is certainly very serious: seasonal flu, a serious threat in and of itself, has a case fatality rate around 0.1 percent in the United States, so this coronavirus is about 20 times as deadly (though again, this number may get much better or worse depending on the kind of care we can provide).*

There are also enough examples of mild or barely symptomatic COVID-19 cases and a long enough incubation period that this disease will almost certainly not be contained: we can’t expect to reliably detect everyone who’s ill and infectious, as we could with the SARS 2003 epidemic where the victims always exhibited high fever and thus were easier to identify and isolate.

All of this means that the only path to flattening the curve for COVID-19 is community-wide isolation: the more people stay home, the fewer people will catch the disease. The fewer people who catch the disease, the better hospitals can help those who do. Crowding at hospitals doesn’t just threaten those with COVID-19; if emergency rooms are overwhelmed, more flu patients, too, will die because of lack of treatment, for example.

Community-wide isolation also means that people will depend on deliveries for essentials: in ground-zero of Hubei, for example, that’s what’s happening. But there are only so many delivery workers and while deliveries are better than people going shopping, it’s still a risk to everyone involved. So if fewer people need deliveries, then fewer people will get sick, and more people who need help such as the elderly can still get deliveries as the services will be less overwhelmed.

Here’s what all this means in practice: get a flu shot, if you haven’t already, and stock up supplies at home so that you can stay home for two or three weeks, going out as little as possible. The flu shot helps decrease the odds of having to go to the hospital for the flu, or worse yet, get both flu and COVID-19; comorbidities drastically worsen outcomes.

Staying home without needing deliveries means that not only are you less likely to get sick, thus freeing up hospitals for more vulnerable populations, it means that you are less likely to infect others (while you may be having a mild case, you can still infect an elderly person or someone with cancer or another significant illness) and you allow delivery personnel to help out others.

If you are in a position of authority, that means figuring out how to help people stay at home, by preparing for and allowing for remote work, or allowing for future work to make up for missed days and other similar plans. Households and others who employ part-time help can do this, too: continue paying the cleaners; it can be reconciled later: without pay, people will not be able to prepare and or stay home.

If you live in a regular household, here’s a handy, one-page guide on what you need, with up-to-date information on top, but it is essentially this: potable water (that’s a general just-in-case item for all emergencies), shelf-stable food (doesn’t need refrigeration, again just-in-case), your prescription medication and a few basic medical supplies (first aid/your usual over-the-counter meds). Depending on the composition of your household, things to keep you busy (books, board games, toys).

Many are trying to stock up on masks, and many places have already run out—giving us a taste of what it means not to flatten the curve. If everyone gets masks all at once, there is just no way to keep up. However, don’t worry if you cannot find masks; those are most important for health care workers. Masks are useful for protecting others from your germs and also for making it harder or reminding you not to touch your face. For non–health care people, washing your hands often, using alcohol-based hand-sanitizer liberally and learning not to touch your face are the most important clinically-proven interventions there are (and teaching this to kids is priceless, as they may well be healthy but they are quite the germ vectors!). Clinical studies show amazing results to just washing hands regularly and well (at least 20 seconds!). Of course, if you yourself have any illness (cold or flu!), don’t sneeze or cough on people!

For food, you can just buy two or three weeks’ worth of shelf-stable food that you would eat anyway, and be done; this could include canned food like beans and vegetables, pasta, rice, cereals or oats, oils/fats, nuts and dried fruits. It’s really not that hard because we’re talking two-three weeks, so whatever you get is fine. It doesn’t have to be expensive or super healthy or specialized ready-to-eat meals in camo boxes guaranteed to survive the meteor strike! Rice, beans, salsa, ramen, some sort of cooking oil, oatmeal, nuts and dried or canned fruits and vegetables enough for two weeks can be had at relatively little cost and take up fairly little space.

Why not rely on refrigerated food? Sure, keep your fridge full, but it isn’t the back-up you need for two weeks. I personally don’t think the lights or water are going out. They haven’t in China, even in places like Hubei that are under much more stress, and they didn’t even during the catastrophic Spanish flu pandemic at the end of World War I. However, it’s generally good advice to rely on shelf-stable food and have some potable water in the house just in case there is some sort of temporary hiccup. A portable power bank for your phone that is kept charged is similarly generally useful anyway.

If you need prescription or other medications, it’s a good idea to stock up if possible—if for no other reason than to avoid pharmacies, both to reduce their burden and also to not be in the same line as people who may be ill.

That’s mostly it, for a household, along with whatever will help keep your household entertained and busy.

If you get lucky and no community isolation is necessary in your area? At worst, you can just eat your pantry, or just rotate it so that you have a few days’ worth of food and water—for the next weather event or hiccup.

As a society, there are much larger conversations to be had: about the way our health care industry runs, for example. How to handle global risks in our increasingly interconnected world. How to build resilient communities. How to reduce travel for work.

Those are all important discussions, and nothing in this short article replaces that. However, the practical steps facing households are immediate and important; for the sake of everyone else, prepare to stay home for a few weeks. You’ll reduce your own risks, but most importantly, you will reduce the burden on health care and delivery infrastructure and allow frontline workers to reach and help the most vulnerable.

Read more about the coronavirus outbreak here.

*Editor’s Note (2/27/2020): This sentence was edited after posting to correct the fatality rate for seasonal flu.