—Photo by JellyBean Pictures

Most moms know to quarantine a tot with a fever. But what about a lingering cough or a runny nose? There are a lot of conflicting opinions out there about what’s contagious when, where germs live—and for how long. With cold and flu season settling in, we asked Dr. JJ Levenstein, co-founder of MD Moms, to set the record straight on the cooties.

Kids’ colds can last forever. When are they actually contagious? For most viral illnesses, the prodromal (or early) phase—generally that day your child is a little “off”—starts the period of contagion. And for the first few days of a cold, when coughs, sneezes, and snot are at a maximum, a child is contagious.

And what’s the rule with fevers? Keep your little one out of contact with others until fever is gone for at least 24 hours—without fever relief medicine. For influenza, the fever typically lasts 4 to 7 days. A child is contagious on all of those days, and likely for a few days more after the fever breaks, especially if cough or nasal secretions are still present.

Snots are gross, but are they always contagious? Not always. Clear runny noses in the setting of sneezing, watery eyes, and itching usually indicate allergies, and therefore are not contagious. Unrelenting green, yellow, or cloudy snots coming from both nostrils for longer than 8 to 10 days may indicate a sinus infection, which is a secondary complication of a simple virus and is not contagious.

What about a lingering cough? This is a tough question. Chronic coughs can come from many sources, ranging from sinus infections to bronchitis to post-nasal drip from allergies to impacted wax in the ear canals (believe it or not). So if your baby has a cough for longer than the usual 5-to-7-day duration of a cold, circle back to your health care provider to see what’s going on.

Are indoor play spaces as germy as they seem? Yes. Viruses and bacteria can live on inanimate objects: toys, ball pits, market carts, and banisters can all house unwelcome germs.

Ew. Gross. So exactly how long can germs “live” on surfaces like toys and elevator buttons? 
Estimates range from minutes to up to 48 hours. Hard surfaces seem to harbor germs longer than fabrics or tissues. Flu viruses outlast typical cold viruses.

So when a baby class or play space claims to clean its toys, how can we be sure their cleaning method is effective? It’s basically an impossible expectation unless they are cleaned between all classes with bleach, cleansing wipes, or alcohol.

What about airborne germs? Airborne germs live for hours after a sneeze or cough.

Really? Wow. Dare we even ask about tech gadgets? It’s as bad as you’d imagine. To clean a remote control, cell phone, or keyboard, disconnect it from power, pull out the batteries, and take a bleach-saturated wipe or alcohol wipe and give a good rub. Let sit for a few minutes until dry, then put the batteries back in.

We already know that hand-washing is key. How often should kids do it, and with what? If your little one loves to touch everything, periodic hand cleansing is the name of the game. Older kids who are not thumb-suckers should wash before all meals and snacks, and after the toilet. Younger ones should wash frequently, especially outside the safe confines of home. Good old soap and water is the safest. If that’s not available, cleansing wipes are reasonable, as long as you apply friction for 15 to 30 seconds.

Is the fresh air thing an old wives’ tale, or does opening a window actually help kill germs during or after illness? Ventilating a room sweeps potential airborne germs to the outside, so it may decrease the potential germ load hovering over a family.  If weather permits, ventilation is always a good idea.