The most effective ways to prevent COVID-19 are staying up to date on vaccination, wearing a well-fitting respirator in crowded indoor spaces, and improving the air quality in rooms where you spend time. None of these measures alone is perfect, but layering them together dramatically lowers your risk. Here’s what works, how well it works, and how to put each layer into practice.
Get the Updated Vaccine
Vaccination remains the single most important step for preventing severe illness. The CDC recommends the 2025–2026 COVID-19 vaccine for everyone ages 6 months and older. If you’ve been vaccinated before, you’re eligible for the updated dose at least 8 weeks after your last shot. If you’ve never been vaccinated, you can start with a single dose (two doses for infants under 2 and for adults 65 and older using certain products).
For adults 65 and older, a second dose is recommended about 6 months after the first. The same applies to anyone 6 months or older with moderate or severe immune compromise, and those individuals can receive a third dose or more through shared decision-making with their provider. Three vaccine options are available for adults: two mRNA vaccines and a protein-based option from Novavax for those who prefer a more traditional vaccine technology. Children under 12 have fewer product choices, but at least one option covers every age group down to 6 months.
Protection from any COVID vaccine fades over months, which is why updated formulations are released to match circulating variants. Thinking of it like the annual flu shot is a reasonable mental model: get the newest version each year, especially before fall and winter surges.
Wear a Respirator That Actually Filters
Not all masks offer the same protection. A CDC-funded study of over 500 people in California found that wearing an N95 or KN95 respirator in indoor public settings was associated with an 83% reduction in the odds of testing positive for COVID-19, compared with wearing no mask at all. Surgical masks cut the odds by about 66%. Cloth masks showed no statistically significant benefit in that same analysis.
The key difference is filtration and fit. N95 and KN95 respirators are designed to seal around your nose and mouth, filtering at least 95% of airborne particles. Surgical masks filter reasonably well but have gaps at the sides. If you’re going to mask in a high-risk situation, like a crowded flight, a hospital waiting room, or an indoor event during a surge, an N95 or KN95 gives you meaningfully better protection than a loose surgical mask.
Fit matters as much as the material. A respirator that gaps at the bridge of your nose or hangs loosely under your chin loses much of its advantage. Look for models with adjustable nose wires and head straps rather than ear loops, and try a few brands to find one that seals comfortably against your face.
Improve Indoor Air Quality
COVID-19 spreads primarily through respiratory particles that hang in the air, especially in poorly ventilated indoor spaces. Moving more outdoor air through a room and filtering the air already inside are two of the most effective environmental controls available.
The CDC recommends aiming for 5 air changes per hour (ACH) in public indoor spaces, achieved through outdoor air ventilation alone or through a combination of ventilation, filtration, and air treatment. At home, you can move toward that target with a few practical steps: open windows on opposite sides of a room to create cross-ventilation, run bathroom or kitchen exhaust fans, and use a portable HEPA air purifier sized for the room. The EPA recommends upgrading HVAC filters to MERV 13, or the highest rating your system can handle. Higher-rated filters catch smaller particles, including the droplet nuclei that carry the virus.
A simple DIY option is a box fan with a MERV 13 furnace filter taped to the back. It won’t match a commercial HEPA unit, but it meaningfully reduces airborne particle counts for under $30.
Don’t Worry Much About Surfaces
Early in the pandemic, people wiped down groceries and mail. That turns out to be largely unnecessary. The CDC’s own assessment found that each contact with a contaminated surface carries less than a 1-in-10,000 chance of causing infection. The virus spreads overwhelmingly through the air, not through touch. Regular handwashing with soap and water is still good hygiene and prevents plenty of other infections, but obsessive surface disinfection doesn’t meaningfully reduce your COVID risk.
Use Rapid Tests Strategically
Rapid antigen tests are useful, but they have real limitations you should understand. Their sensitivity on days when a person has no symptoms is only about 18% compared to PCR testing. That means a negative rapid test in someone without symptoms misses the vast majority of infections. Even when compared against viral culture (which measures whether someone is actively contagious), sensitivity on asymptomatic days is only around 45%.
This doesn’t mean rapid tests are useless. They’re most reliable when you already have symptoms, when you test on two consecutive days, and when you swab both your throat and nose rather than just your nose. If you’re planning to visit someone at high risk, testing twice over 24 to 48 hours and watching for any symptoms gives you a better safety net than a single negative test the morning of your visit. A positive rapid test is highly reliable; it’s the negative results that deserve skepticism, especially without symptoms.
Layer Your Protections
No single measure eliminates the risk entirely. Vaccines reduce severe disease more than they prevent infection. Masks work best when everyone in the room wears one, but they still help even when only you do. Better ventilation dilutes airborne virus but can’t remove it all. Testing catches some infections but misses others.
The practical approach is to layer protections based on the situation. During a known surge or when spending time with someone who is elderly, immunocompromised, or otherwise vulnerable, stack as many layers as possible: make sure your vaccination is current, wear an N95 in transit, meet in well-ventilated spaces, and test beforehand. During quieter periods with low community transmission, you can reasonably relax some of those layers while keeping the basics in place. The goal isn’t perfection. It’s reducing the probability of transmission enough to protect yourself and the people around you.