8 Mistakes That Make You More Likely to Spread COVID-19

With several COVID-19 vaccines available, you may be wondering if you can let down your guard. The answer: It depends.

If you are fully vaccinated, returning to a semblance of your pre-pandemic life is OK, according to the Centers for Disease Control and Prevention (CDC). You'll still need to follow local guidelines and mask up on public transportation, but in general, you can resume everyday activities.

But if you're midway through your two-shot vaccine, or haven't yet been vaccinated, don't throw caution to the wind. Keep yourself safe, and help tamp down the spread of the virus by avoiding these eight mistakes.

Strapping on a mask to ride public transportation or attend an outdoor community event is a good habit to get into because the more people you interact with and the longer that contact lasts, the greater your risk of acquiring and spreading COVID, according to the CDC.

If you aren't fully vaccinated, exercise that same level of vigilance even if you're only having brunch with a few friends or watching a game on your neighbor's widescreen. On the CDC's sliding scale of risk, an indoor event with a mix of vaccinated and unvaccinated people is considered "safest" for vaccinated people, but "less safe" for unvaccinated people.

People tend to get lulled into a false sense of security in these more intimate settings.

"They're letting their guards down when they're in small groups and gatherings with their friends, not realizing that some of them could harbor the infection and are not really being as meticulous with social distancing or with face coverings," says Amesh Adalja, MD, senior scholar at the Johns Hopkins Center for Health Security in Baltimore.

Basically, for unvaccinated people, if you're with anyone who lives outside your household, you'd be wise to wear a mask, wash your hands and keep at least six feet of distance between you.

Mask "fails" are frustratingly common: masks that dangle from one ear, droop below the nose, peak out of a pocket.

The coronavirus doesn't care if you had good intentions. If you aren't vaccinated, you need to mask up properly to avoid possibly spreading the virus to other people (and to protect yourself from infection, according to a CDC analysis).

If you're not in the habit of putting on a mask, getting used to wearing one can be difficult, but then it becomes like a "second skin," says Hana El Sahly, MD, associate professor of molecular virology and microbiology at Baylor College of Medicine in Houston.

A quick refresher from the CDC: Your mask must completely cover your mouth and nose and fit snuggly around your face without gaps.

When COVID first began infecting people in hot spots across America, masks were in short supply. Now, with ample options on the market, why not replenish your stash with those that work best to cut your risk of transmission?

Airflow videos from the National Institute of Standards and Technology (NIST) suggest masks with exhalation valves don't make the cut.

"Most exhalation valves consist of a small, flexible tab that acts as a one-way check valve, opening upon exhalation and closing upon inspiration," writes NIST research engineer Matthew Staymates, author of a November 2020 ​Physics of Fluids​ study that included the videos. They're designed to allow exhaled air to pass through the mask, and that's the problem.

"These videos show how the valves allow air to leave the mask without filtering it, which defeats the purpose of the mask," he explains in a NIST news release.

Sophia Thomas, DNP, a doctor of nursing practice and president of the American Association of Nurse Practitioners, tells LIVESTRONG.com she's had a couple of COVID-positive patients who wore valve masks and infected other people close to them.

So what type of mask should you be wearing instead? The CDC recommends two or more layers of washable, breathable fabric. While a September 2020 ​Science Advances​ study found N95 masks — the fitted type used by health care workers and first responders — are best at blocking respiratory droplets, the CDC discourages their use by the general public so as not to deplete supplies. The same study found three-ply masks worked almost as well.

Be mindful when you get together indoors with others.

Viruses in aerosols "can remain suspended in the air for many seconds to hours, like smoke, and be inhaled," explain leading U.S. environmental and public health scientists in the journal ​Science​. Their October 2020 letter to the editor cautions that these airborne particles, especially in poorly ventilated indoor spaces, can lead to superspreading events.

Again: This applies only to people who aren't fully vaccinated. Going to the gym, movie theater, a full-capacity religious service and eating indoors in a restaurant are all considered "least safe" activities for the unvaccinated, according to risk assessment from the CDC. But for those who are fully vaccinated, these activities are deemed "safest."

Don't assume that you're in the clear when it comes to COVID-19 if you're young and healthy. Unvaccinated young adults are quite capable of getting the infection and passing it along to others.

Data from the last week of May 2021 shows that adults between the ages of 18 to 48 made up 39.9 percent of hospitalizations due to COVID-19, according to the CDC. That's higher than adults who are 65 or older, who accounted for 27.9 percent of hospitalizations that same week.

The rising rate of severe COVID-19 cases in younger people may be due to a difference in vaccination rates: 80 percent of adults who are 65 or older are fully vaccinated, compared to 47 percent of adults ages 18 to 64, per June 2021 data from the Mayo Clinic.

Anyone who is old enough to get vaccinated should do so, for your own safety and the safety of others around you, such as people who are immunocompromised. As much as 30 percent of infections are asymptomatic, based on CDC estimates. That means you can have COVID, not know it and inadvertently infect others.

If you had COVID and recovered, your immune system mounted antibodies to fight off the infection. That's great news, but don't count on it as a cloak of protection against future infections. Scientists don't how how long such immunity lasts.

It's rare to get reinfected after having COVID-19, per the CDC — but rare is not impossible. For that reason, the CDC recommends that people who have had COVID-19 get vaccinated.

Whether or not you've had COVID-19, if you haven't received your vaccine yet, you still need to wear a mask, social distance and wash your hands to avoid contracting and spreading the virus.

A normal body temperature is 97 to 99 degrees Fahrenheit, more or less, according to the Cleveland Clinic. But if you waltz out into the world thinking fever-free means COVID-free, you could be putting other folks at risk.

"Temperature checks are very difficult to use as an indicator," Thomas says.

A surface temperature reading might not be very reliable, say, if you've been in a chilly room for a period of time. And if you took a fever-reducing medicine like acetaminophen or ibuprofen before getting your temperature checked, you're less likely to register a fever.

A September-October 2020 report in ​Travel Medicine and Infectious Diseases​ cautions about the futility of temperature checks as a COVID-19 indicator, especially in young adults. The small study involved 84 mostly young men (in basic training with the Swiss Armed Forces) who had twice-daily temperature checks over a 14-day period following their COVID diagnosis.

A temperature cutoff of 100.4 identified only a minority of cases, the study found, while a higher cutoff of 101.3 still missed 92 percent of cases at the time they presented with symptoms.

In September 2020, the CDC announced a shift in its strategy for screening certain international airline passengers. It now acknowledges that some people with COVID may have no symptoms or fever at the time of screening. However, the agency continues to recommend temperature checks in the workplace.

Seasonal allergies and everyday colds can make it hard to know what's making you miserable. Please don't brush off symptoms.

You might need testing to firm up a diagnosis. If it's the flu, your doctor can prescribe antiviral medicine to speed your recovery. If it's COVID, you need to self-isolate.

A test doesn't change the course of the disease, explains Thomas. "But it does reassure individuals that, yes, I do have COVID-19. I do need to stay home, and I do need to isolate and I do need to notify others of my disease so they can take the proper precautions."