UC Davis infectious disease experts weigh in on common novel coronavirus (COVID-19) mistakes and myths and give the science behind them.


hand touching door handle

Contaminated surfaces aren't the highest COVID-19 risk

The primary route of COVID-19 infection isn't by touching contaminated surface but through the respiratory system, said Dean Blumberg, chief of pediatric infectious disease at UC Davis Children's Hospital. People should focus on wearing masks and social distancing and less on sanitizing surfaces.

Tests have found traces of COVID-19 on surfaces, but no research has established that the virus is viable in those places, partly because research has veered in other directions.


wiping table with cleaning product

Cleaners need at least 1 minute to disinfect

Many people are unaware that most cleaning products should stay wet on a surface for at least one minute, potentially up to 10 minutes, before wiping it down, according to Natascha Tuznik, a UC Davis Health assistant clinical professor of infectious diseases.

Learn more about contact time of a cleaner from the Environmental Protection Agency's List N Tool: COVID-19 Disinfectants


woman using hand sanitizer

Hand santizer do: Rub your hands until they're dry

When using a hand sanitizer, don't just let your hands air dry. For the sanitizer to be most effective, rub your hands together until they're dry, Tuznik said.

Hand sanitizers should be at least 60% alcohol. The most commonly used safe version is ethanol, also known as ethyl alcohol.

Don't use a sanitizer with methanol. The U.S. Food and Drug Administration (FDA) warned that methanol is toxic and can be absorbed through the skin. It also warned that more than 100 sanitizers have been mislabeled as ethanol. You can find the list of hand sanitzers to avoid on the FDA's website.


wearing gloves pushing grocery basket

Wearing gloves isn't necessary

There are no studies that show disposable gloves increase protection against COVID-19. The virus won’t infect you through your well-moisturized hands, and remember, surface contact is not a primary source of COVID-19 transmission. If you do infect yourself, it would be from touching your face – with or without gloves.


large floor fan

Floor fans aren't good

Large floor fans create a focused blast that pushes air and the virus a long way. A number of studies show you can get infected at a good distance because of those large fans, Tuznik said.

Besides gyms – most are closed right now – these fans are also common in outdoor restaurants and other venues where people gather.


man wearing pollution mask with filter

Masks with filter ports are dangerous

These type of masks are designed for people working around caustic fumes or chemicals, Tuznik said. They force out the air you’re breathing through the port. Instead of protecting someone from you, they propel your breath even farther and more forcefully.

N95s with the filter in the middle also do not prevent someone from spreading the virus. They filter air coming in but do let air out.


nurse at blood collection tubes

Surviving COVID-19 doesn't necessarily make you immune

Experts still don't know if a recovered patient is immune and how long immunity lasts, Blumberg said. Our best estimates from similarities with other coronaviruses is that immunity will last a few months. That’s why it’s likely people will have to get booster shots once a COVID-19 vaccine is developed.


girls wearing masks

COVID-19 herd immunity isn't the best option

Herd immunity without a vaccine will come at a great cost to human life, according to Blumberg. Worldwide, 70-90% of people need to be infected with novel coronavirus, and currently, we’re at just 2-3%.

The fear is that too many people will get sick at the same time and hospitals will be overrun, like we saw in New York and Italy, Blumberg said. If this happens, there won't be enough hospital beds, doctors and nurses to care for people.


crowded beach

Even if people look healthy, still avoid gatherings

A common explanation some people give when going to beaches and large gatherings is that they feel safe because everyone "looks" healthy. The Centers for Disease Control and Prevention (CDC) estimates about two-thirds of COVID-19 infections come from people who show no symptoms. That's why there's such an emphasis on wearing masks, social distancing and avoiding large gatherings.