
With the omicron COVID variant proving more transmissible than any other, there's a very good chance you'll catch it, no matter how careful you are. To keep you safe, Dr. Tatiana Prowell, an Associate Professor of Oncology at Johns Hopkins School of Medicine, who serves people with COVID-19, tweeted a viral thread to lay out exactly what you should do the minute you or someone you know has symptoms (and she described the symptoms, too). Read on for the exact steps—and to ensure your health and the health of others, don't miss these Sure Signs You've Already Had COVID.
This is the First Thing to Do if Someone Has Omicron Symptoms

"The first thing to say is that if someone has COVID-19 symptoms (Omicron most common: nasal congestion/runny nose, scratchy sore throat, fever, and aches), you have to assume they have it. You may not have a test (urgent cares are still open and do) or they may still be negative," said Dr. Prowell. "You, as the person exposed to the one with symptoms, have to assume that you both do and don't have Omicron too. Wait, what? I mean: assume you could infect others now and take care to avoid exposing them, BUT don't assume it's too late for you to avoid getting it." She added: "Especially in households with vaccinated (and boosted) family members, I have seen people manage to limit Omicron to the first person who was infected. This COVID variant is incredibly contagious, but It CAN be done. Don't give up on the idea!"
Mask Up and Ventilate. "Shared Air is the Enemy."

"If you have N95/KN95/KF94 masks, get in them immediately," said Dr. Prowell. "If you have only one, put the sick person in it for source control. If you have >1 but not enough for all. put the sick one and the highest risk (older, immunocompromised) people in them. Then get outside, and leave the door open." She added: "Fresh air is a friend and shared air is an enemy. The more you can ventilate your house, now and until this is over, the better. You want the concentration of Omicron in air as low as possible. This lowers odds of infection and may make you less sick if you do get infected."
"Filter That Omicron"

"Plan to bundle up if you're in a cold climate, because you're going to need to leave windows and doors open enough for air exchange, especially for the next five days or so, and a cross draft. If you have a fresh HVAC filter, change it. If a hardware place is open, get a MERV13 HVAC filter. (Amazon has too.)" Added Dr. Prowell: "Run the fan on your thermostat on high. Filter that Omicron virus!" And: "If you need supplies of any kind, please do curbside pickup or same-day delivery or drive-thru. No one exposed should be indoors in public, and def not the one with symptoms, to prevent further spread."
What to Do If You Don't Have the Right Masks

"If you don't have any N95/KN95/KN94 masks, please see if a nearby friend or neighbor has unused ones you can have and order them replacements. The nonprofit Project N95 is a great place to get them. Your backup plan for right now is a surgical mask." She added: "A surgical mask (ASTM level 3, 3-ply is best) has good filtration but usually not good fit. There are often gaps. Knot ear loops where they join the mask and then tuck to improve the mask fit. Here's a short video demo. Put a cloth mask over the surgical mask," said Dr. Prowell.
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Create a Space For the Infected Person

"Now it's time to create the space where the infected person or people will isolate for 10 days to let Omicron run its course," said Dr. Prowell.
- "Pick a room w/ windows to open and its own door if your home allows. Today, put a fan there that can be used to improve air exchange. Put a thermometer, an O2 sat monitor, good masks. Go get a MERV13 filter for your HVAC at Home Depot or Lowe's or online. While here, get the stuff to build a simple, inexpensive, highly-effective Corsi-Rosenthal box." (We found instructions for making one here.)
- "If you have a little microwave or a mini fridge or cooler or something, put those in there too, along w/ food/snacks/rehydrating drinks. The goal is to create a space where the ill person can be as self-sufficient as possible to minimize their need to enter the main space."
- "Pretend you're going away for a long weekend. Make sure the room has stuff you'd need—basic toiletries, a phone charger, etc. I assure you I am not a prepper….You need to prep."
- "It seems like overkill now, but I promise you when someone tests positive and they will (come back and say hi to me), you'll be delighted to have the quarantine suite ready to go. Decide who will stay with the ill person if it's a kid (or anyone dependent on you) if only one is ill."
- "Get a few rapid tests online so you can rapidly determine if anyone else is positive. That may make the above decision simple. Make sure you have good masks for the ill person and others. Get them today. You don't want to be faced with needing to go out to stores when you should be at home in quarantine due to a close contact exposure. Though vaccines work to reduce risk, especially of severe/fatal COVID-19, Omicron is still far more likely to infect you than any prior COVID variant."
How to Tell if the Infected Person is "OK"

"This whole scenario assumes that things are going OK with the person who has Omicron," said Dr. Prowell. "How do you know if they are OK? If you have a pulse oximeter (O2 sat monitor)—the thing doctors put on your fingertip to measure O2—use it." (For how to use it, see here.) "If you don't have a pulse oximeter, many pharmacies carry them. They are over the counter. Ask the pharmacist if you don't see them. You can order them online from many places too. Get one highly rated by many people. They need not be expensive. $15 gets a very good one."
"Some of your devices (smart watches, fitness trackers) can detect heart rate (60-100 normal for adults) and less reliably O2 levels. If you have them and they read low O2 levels, def do call a doctor or seek care. Video calls on phone or computer are helpful to check on the sick as well." Ask your doctor if you are unsure what to do about how you feel.
What to Do if The Person is High Risk

"If the person with Omicron is high-risk (especially immunocompromised, organ or bone marrow transplant, active cancer, pregnant, diabetes, older, etc), they should contact a doctor even if they seem ok. There are outpatient treatments that significantly lower risk of being hospitalized. These include monoclonal antibodies (some brands no longer work vs Omicron, but 1 called sotrovimab remains effective). It is given IV as a single dose. There are also two types of pills taken for 5d at home. All are in short supply at the moment." she added: "All of these things to treat outpatients with Omicron, the monoclonal antibody sotrovimab, as well as the pills (Paxlovid) and (molnupiravir) are new, so they are being reserved for higher-risk folks while supply increases."
If You Are Not the Sick Person

"If you are not the sick person, but one of the exposed, and you can walk-up/drive-up (NOT indoors and ONLY in a mask!) to get vaccinated, do it. If age 16+ and 6+ mos post dose 2 of vaccine (or 2+ post J&J), go get boosted now! The booster protects within a week!"
Final Word From the Doctor

"Know that if you are indoors with people from outside your household, you WILL be exposed to Omicron. The only Q is whether you'll get infected. If you wear a very good mask and are careful, you CAN prevent it." So follow the public health fundamentals and help end this pandemic, no matter where you live—get vaccinated or boosted ASAP; wear an N95 face mask, don't travel, social distance, avoid large crowds, don't go indoors with people you're not sheltering with, practice good hand hygiene, and to protect your life and the lives of others, don't visit any of these 35 Places You're Most Likely to Catch COVID.