The most effective ways to avoid viruses come down to a handful of habits: washing your hands properly, improving the air you breathe indoors, staying current on vaccines, and supporting your immune system. None of these are complicated on their own, but the details matter more than most people realize. A 10-second rinse under the faucet, for example, does almost nothing compared to a full 30-second wash with soap.
Why Handwashing Beats Hand Sanitizer
Soap and water is the single most reliable way to remove viruses from your hands. A 30-second wash with soap completely eliminated detectable norovirus particles (the most common cause of stomach bugs) from finger pads in lab testing. Alcohol-based sanitizers, by comparison, showed inconsistent results against the same virus, reducing it far less effectively.
That said, sanitizer isn’t useless. Alcohol-based hand disinfectants wiped out influenza and rotavirus completely within 30 seconds. The problem is that several other common viruses, including adenovirus and parechovirus, resisted alcohol even after three full minutes of contact. So sanitizer works well against some viruses and poorly against others, while soap and water works well against nearly all of them.
The technique matters: wet your hands, lather with soap for at least 20 seconds (scrubbing between fingers, under nails, and the backs of your hands), then rinse and dry. The friction of scrubbing physically dislodges viral particles, which is why soap succeeds where alcohol sometimes fails. Use sanitizer with at least 60% alcohol when soap isn’t available, but treat it as a backup rather than a replacement.
How Viruses Spread Through the Air
Respiratory viruses like influenza, COVID-19, and RSV travel primarily through tiny droplets and aerosols released when an infected person breathes, talks, coughs, or sneezes. Larger droplets fall to surfaces within a few feet. Smaller aerosol particles can hang in the air for hours, especially in poorly ventilated rooms. This is why crowded indoor spaces with stale air are where most respiratory infections spread.
The CDC recommends aiming for five or more air changes per hour of clean air indoors. You can get there through a combination of your building’s ventilation system, opening windows, and using portable air purifiers with HEPA filters. Even cracking two windows on opposite sides of a room creates cross-ventilation that meaningfully dilutes airborne virus concentrations.
The Role of Humidity
Indoor humidity levels influence how long viruses stay infectious in the air, but the relationship is more nuanced than “higher is better.” Enveloped viruses like influenza tend to survive longest in dry air below 50% relative humidity. Their viability drops in the middle range of roughly 50% to 70%, where evaporation lowers the pH of airborne droplets enough to damage the virus. Nonenveloped viruses, like those causing many stomach and respiratory illnesses, tend to be more stable at higher humidity.
Since no single humidity level neutralizes every virus, keeping your indoor air between 40% and 60% relative humidity is a reasonable target. This range also happens to be comfortable for most people and reduces the drying of nasal passages, which are part of your body’s first line of defense against infection. A simple hygrometer (available for a few dollars) lets you monitor this.
Masks Still Work When You Need Them
N95 and KN95 masks filter at least 95% of airborne particles in the size range that matters most for viruses (around 100 to 300 nanometers). At larger particle sizes, their filtration efficiency climbs above 99%. Surgical masks are less consistent, filtering roughly 53% to 75% of the smallest aerosol particles and up to 92% of larger ones. The gap between an N95 and a surgical mask is significant in high-risk situations like a crowded clinic waiting room or a long flight during a respiratory virus surge.
Fit matters as much as filtration. An N95 that gaps at the sides or nose performs no better than a surgical mask. If you’re going to wear one, press the nose wire firmly and check that air flows through the mask rather than around it. For everyday errands, a well-fitting KN95 offers equivalent protection to an N95 and is easier to find at pharmacies.
Don’t Touch Your Face (and Clean Surfaces)
Your eyes, nose, and mouth are direct entry points for viruses. The average person touches their face 16 to 23 times per hour without thinking about it, transferring whatever is on their hands straight to mucous membranes. Building awareness of this habit is one of the simplest things you can do during cold and flu season.
Surface contamination is especially relevant for stomach viruses. Norovirus can remain infectious on hard surfaces for up to two weeks. That’s why a single sick family member often triggers a household outbreak: the virus lingers on doorknobs, light switches, faucet handles, and countertops long after symptoms resolve. Standard cleaning sprays don’t always kill norovirus. A bleach-based solution (about 5 tablespoons of household bleach per gallon of water) is more reliable for disinfecting surfaces after someone in the house has been sick.
Keep Your Vaccines Current
Vaccination remains the most effective tool against several of the most dangerous viruses. The current CDC immunization schedule for adults recommends one dose of flu vaccine annually for everyone 19 and older. Adults 65 and over are recommended to receive a higher-dose or adjuvanted version for stronger protection. For COVID-19, adults under 65 need one or more doses of the current season’s updated vaccine, while those 65 and older are recommended two or more doses. RSV vaccines are now available for adults in their 60s and older.
Timing matters for flu and COVID vaccines. Getting vaccinated in early fall, before peak circulation begins, gives your immune system about two weeks to build full protection. If you miss that window, getting vaccinated later in the season still helps.
Nutrition That Supports Immune Function
Your immune system needs adequate vitamin D and zinc to mount an effective response to viral infections. Research on COVID-19 patients found that those with normal vitamin D levels (above 20 ng/mL in blood tests) had roughly 80% lower odds of developing general symptoms compared to those who were deficient. People with insufficient but not severely low levels still saw meaningful protection.
Most adults can maintain adequate vitamin D through a combination of moderate sun exposure, foods like fatty fish and fortified dairy, and supplementation during winter months when sunlight is limited. If your levels are low, around 40 micrograms (1,600 IU) of vitamin D3 daily has been studied as a preventive dose. For zinc, a daily intake of up to 25 milligrams through food and supplements supports immune readiness without risking the nausea and copper depletion that higher doses can cause. Good dietary sources include meat, shellfish, legumes, seeds, and nuts.
These nutrients don’t replace vaccines or hygiene. They fill gaps that make your body less prepared to fight off infections it encounters.
Putting It All Together
Virus prevention works in layers. No single measure is perfect, but combining several of them dramatically lowers your overall risk. Wash your hands with soap for 30 seconds after being in public spaces, before eating, and after using the bathroom. Keep indoor air moving and reasonably humid. Wear a well-fitting N95 or KN95 in crowded, poorly ventilated spaces during outbreaks. Stay up to date on your annual vaccines. Disinfect shared surfaces when someone at home is sick. Make sure you’re getting enough vitamin D and zinc, especially in winter.
Each of these steps removes a percentage of risk. Stacked together, they make it far less likely that a virus finds its way in.