In case you haven’t heard, some are suggesting that we’ll be partying, eating out, and going back to work in a few weeks. Yes, this could be a disaster. However, whenever we do restart the economy, we should do it safely. And one of the best ways to do that is for everyone to start thinking and behaving like a microbiologist.

My background is in environmental microbiology — which means I’ve spent over a decade thinking about unseen microbes lurking in the environment around us. Although the coronavirus is an evil jerk, it’s not without its weaknesses. It can’t move on its own. It can’t multiply outside a living body. And it’s relatively wimpy … easily killed by soap, high heat, and other disinfectants.

Another added weakness of COVID-19 is that — if you could see it how I see it — preventing its spread can be almost like a game of pinball. The virus comes charging out of someone’s hole (mouth, nose, or butt), and then you just need to prevent it from entering one of your holes. And even if it eventually makes its way in, if you manage to stall it long enough (well … days), it loses its ability to infect you.

Here are all the germ holes (orifices) in your body and how they relate to the coronavirus:

This means that the only holes we need to worry about are, in order of importance: our mouths, noses, anuses, and tear ducts. Combined, these hot spots cover an area that’s smaller than the palm of your hand.

The following tips are not fully comprehensive—I’m sure you’ll think of some of your own as you go through this list. In fact, I encourage you to because this guide is meant to serve as a starting point to help you think about this problem proactively.

Here’s a microbiologist’s orifice-by-orifice guide to preventing COVID-19’s spread.

Mouths

Our mouths are the main transportation hub for SARS-CoV-2, the virus that causes COVID-19. An infected person’s sputum (saliva + mucus) can carry around 500 million viruses per teaspoon. Of course, the main target is the lungs, but our mouths (and noses) are the gates to the respiratory system.

When a person is infected, the fluid that comes out of their mouths can reach us in a variety of ways. They can pass it to us directly through kisses and other slobbery activities. They can also pass it to us indirectly — through shared food or drinks, through the air in tiny droplets, and through objects they’ve touched or coughed on. You can reduce oral transmission in the following ways.

Preventing other people’s saliva or phlegm from entering your body:

• Don’t share drinks, food, utensils, vape pens, or wind instruments with others.
• Pay attention to your shoes, and consider taking them off at the front door. In a patient’s hospital room, researchers found that the highest density of virus was on the floor, where the spray from the patient’s coughs settled to the ground. When they sampled different parts of a worker’s body who went into the patient’s room, only their shoes tested positive for the virus.
• Avoid public pens and pencils — especially ones with chew marks. Carry your own pen.
• Avoid buffets and family meals where multiple people are handling the serving utensils.
• Wash your hands after touching anything that was handled by someone else. Dirty dishes and half-eaten food could be particularly ripe with saliva.
• If you are nearby someone who coughs or sneezes, gently exhale through your mouth and nose as you swiftly leave the room. Don’t waste any seconds to glare disapprovingly. Go wash your hands and face with soap and water. Do not immediately reenter the room because it takes time for the spittle spray to settle out of the air (it’s impossible to say how long because it depends on the humidity and ventilation). Have the offender open a window if possible. If you’re really worried, you could change your clothing and wash your hair.
• The CDC recommends that we wear face masks while in the same room as or looking after infected people who aren’t wearing face masks. Homemade masks are being used in hospitals and in public when disposable masks are unavailable. (I wrote more about face masks here, including links for making them.)
• Don’t follow the advice to drink water every 15 minutes. This advice isn’t based on evidence and might put your face holes at extra risk, especially if you’re wearing a face mask.
• Keep all drinks and food covered in public places. Otherwise, spittle and sputum spray can settle into it.

If there’s any chance you could be infected

• Do not lick, bite, kiss, blow raspberries, sneeze, cough, spit, or suck on anyone or anything that isn’t yours.
• Keep your hands clean, and keep them away from your face.
• Don’t taste any food you’re preparing for others. They can salt it themselves.
• Wear a face mask while in public and while handling food or other items that’ll be touched or eaten by someone else. Even a homemade mask is better than nothing.
• While at the store, don’t touch anything you’re not planning on buying. Don’t squeeze the avocados. Don’t search for the milk with the best expiration date. Don’t fondle the eggplants.
• If you’re actively coughing or sneezing, unless it’s a medical emergency, don’t go into public or spend time with others. Surgical masks can’t contain all your infectious spray when you cough or sneeze.
• If you’re in public and suddenly need to cough or sneeze, cover your face and try to do it away from others in a well-ventilated area. Whatever you used to cover your face (elbow, tissue, pillow, dog) is now potentially contaminated and needs to be kept away from others.

Nose

The liquid that sprays or drips out of a person’s nose might be just as dangerous as the liquid that comes out of their mouths. Nasal swabs of people with COVID-19 test positive for the virus almost as often as sputum. Mouths were simply prioritized over noses because our mouths are large and used for so many different activities. The mouth tips above apply to the nose, with a few extra ones below.

Preventing other people’s nasal liquid from entering your body

• Avoid people who vigorously blow their noses.
• When throwing away dirty tissues, sterilize the surface the tissues were on and wash or sterilize your hands immediately after disposal.
• Be extra cautious of contaminated surfaces in cold climates. People’s noses drip more often in the cold, and coronaviruses stay infectious longer at cooler temperatures.

If there’s any chance you could be infected

• Always disinfect your hands after blowing, rubbing, or picking your nose.
• If you blow your nose, try to do it away from others in a well-ventilated area.
• Carefully dispose of used tissues.
• If your nose is a slow dripper, designate one hand (your nondominant hand) to hold a tissue for dabbing. Never put the dirty tissue down or touch anything with that hand. When you’re done, dispose of the tissue and wash/disinfect your hands.

Anus

COVID-19 doesn’t just infect the respiratory tract — it can also infect the digestive tract. This means infected people can spread the virus through their poop. By different estimates, a third or more of infected people have the virus in their poop. These are some tips to prevent the spread of COVID-19 via fecal matter (which, you might find, is surprisingly abundant).

Preventing other people’s fecal matter from entering your body

• Never eat food prepared or handled by someone who didn’t wash their hands after pooping.
• Don’t shake hands with or touch things handled by someone who didn’t wash their hands after pooping.
• As stated by the NYC Department of Health: No rimming (mouth on anus).
• If a fecal transplant is required, have your donor screened first.
• Coronavirus has been documented to spread through wastewater systems. If you live in an apartment building, run your unused taps and showers for five seconds, twice a day, in order to keep your waste traps functional and protect against wastewater aerosols.
• Avoid public restrooms when possible, especially those with exuberant toilets that spray unseen fecal matter into the air as they flush. Airplanes and cruise ships are often equipped with these.

If there’s any chance you could be infected

• Always wash your hands after pooping.
• If possible, don’t poop in public restrooms.
• If you poop in a public restroom, put the toilet lid down before flushing to decrease the toilet plume of aerosolized fecal matter.

Eyes

A small minority of people infected with the coronavirus carry the virus in their tears. Also, if the virus lands in your eye, it could spread from your tear duct to your respiratory system — which is why medical professionals should wear goggles or face shields in high-risk situations. Although your eyes are your lowest-priority orifice right now, here are some tips to consider.

Preventing other people’s tears from entering your body

• Don’t wipe away anyone else’s tears.
• Don’t let anyone cry on your shoulder.

If there’s any chance you could be infected

• If you cry around others, make sure to cry into a disposable tissue.
• Dispose of the tissue and wash your hands when you’ve finished crying.

Which Rules Should You Follow?

Since COVID-19 is often spread by people who don’t realize they’re sick, the best way to stop this disease is to follow both the set of rules for people trying to prevent themselves from getting infected and the set of rules for people who are infected and trying to prevent spreading the infection. We need to protect ourselves from infection while also protecting those around us.

Without a doubt, there will still be contagious people in our communities whenever we do return to face-to-face public life. But if you can learn to see this virus like a microbiologist, you can also learn how and when to protect yourself and those you love. Don’t be scared; be rational. Just because you can’t see the virus doesn’t mean you can’t figure out where it’s lurking.