NEWS | July 30, 2020

UC Davis experts detail common mistakes about COVID-19

Infectious disease physicians guide us through the science of coronavirus mistakes ranging from hand sanitizer and gloves to herd immunity and long-term impacts

(SACRAMENTO)

Do not blame yourself. The evolution of COVID-19 information has been the most rapid in medical history. It’s hard to keep up.

That’s why even the most well-intentioned people trying to keep themselves, their families and their communities safe from the coronavirus are still making mistakes.

UC Davis infectious disease experts offer this guide to some of the most common COVID-19 mistakes and the science that explains them. Some are mistaken assumptions, some are errors of execution, and some are because research has progressed.

Contact with a contaminated surface: Not the highest risk

This is an area where information has evolved.

“Stop focusing on contact transmission,” said Dean Blumberg, chief of pediatric infectious diseases at UC Davis Children’s Hospital. “That is not a primary route of infection. The primary route is respiratory. If people would focus more on masks and social distancing and less on sanitizing surfaces, we could get this surge of infections to die down quickly.”

Tests have found traces of the coronavirus on different surfaces, but no research has established that the virus is viable in those places, though that’s partly because research has veered in other directions.

Don’t just spray and wipe: One minute of contact time is common minimum

Cleaning is still important, but many people are unaware about the need for most cleaners to remain in contact with surfaces a minute or more.

“A lot of us give something a quick swipe and think we’ve disinfected it,” said Natascha Tuznik, a UC Davis Health assistant clinical professor of infectious diseases. “I don’t know of any product that gets it done with just a swipe.”

So how long should cleaning products stay wet on a surface before you wipe?

“It’s almost always going to be at least one minute,” Tuznik said. “Some are longer. Most people would never think you have to leave something on for 10 minutes.”

To learn the contact time of a cleaner, go to the Environmental Protection Agency’s List N Tool: COVID-19 Disinfectants. It allows people to search by product name, ingredients or registration number for contact time and whether the product works against the SARS CoV-2 virus.

“We see all these pictures of people wiping down things and hear about them giving a place a deep clean if someone tests positive,” Blumberg said. “That’s all useless. Given what we know about contact time and contact transmission, it has no real purpose. It’s for PR.”

Hand sanitizer mistakes: Contact time also required

“We see all these pictures of people wiping down things. We hear about them giving a place a deep clean if someone tests positive. That’s all useless. Given what we know about contact time and contact transmission, it has no real purpose. It’s for PR.”

– Dean Blumberg

“I see people using hand sanitizer then shaking their hands and trying to air dry them,” Tuznik said. “That doesn’t do the trick. For it to be most effective, rub until dry. It doesn’t take much time.”

Also, sanitizer needs to be at least 60% alcohol. The most commonly used safe version is ethanol, also known as ethyl alcohol.

Do not use a sanitizer with methanol. The U.S. Food & Drug Administration 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. Here is the list.

Don’t forget to moisturize

“All the washing and alcohol can take a toll on skin integrity and potentially even create microtrauma and skin tears you don’t see,” Tuznik said. “These can create an entry for all sorts of bad things. Moisturize every night, if not more.”

No real reason for gloves

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, contact is not a primary source of transmission. If you do infect yourself, it would be from touching your face – with or without gloves.

In addition, the World Health Organization recommends you wash or sanitize your hands after taking gloves off.

“Toss the gloves,” Blumberg said. “You’re going to sanitize your hands one way or the other. There is no reason to wear gloves, and they might create a false sense of security that gets people to let their guard down.”

Floor fans are dangerous

“Stay away from the big fans like you see at gyms that blow air across a room,” Tuznik said. “They 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.”

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

“Air flow is good, that’s why outdoor activities are safer,” she said. “But those fans are bad news. When you see one, go somewhere else.”

Masks with filter ports on the side are dangerous.

“Those should be banned,” Tuznik said. “Unfortunately, I see them advertised everywhere. They’re designed for people working around caustic fumes or chemicals – and 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.

“When I see someone wearing those masks, I walk the other way,” she said.

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.

Mistaken assumption No. 1: Surviving COVID-19 makes you immune


Large groups have gathered at beaches and lakes assuming no one will transmit the coronavirus because people look healthy. They are wrong. Two-thirds of transmissions come from people who don’t show symptoms.

“We simply don’t know if that’s true,” Blumberg said. “We don’t know if a recovered patient is immune and how long immunity lasts – weeks, months or years. Our best estimates from similarities with other coronaviruses is that it will last a few months.”

That’s why it’s likely people will have to get booster shots after a vaccine is created.

“Without a vaccine and, probably, booster shots, there’s a good chance you could keep getting COVID-19,” he said.

Mistaken assumption No. 2: If enough people get sick, our herd immunity will make the virus disappear

“If we get to herd immunity without a vaccine, that will come at a great cost in human life,” Blumberg said. “Worldwide, we’re not remotely close to the 70-90 percent of people infected that we need. We’re at 2 or 3 percent.”

The great fear is that too many people will get sick at the same time and hospitals will be overrun.

“We saw what happened in New York, Italy and Iran. Look at Florida,” he said. “People died because there were not enough hospital beds, not enough ICUs, not enough doctors and nurses to care for people. To think we could get there without a huge human disaster, possibly millions of lives, is just folly.”

Mistaken Assumption No. 3: Everyone looks healthy so it must be safe.

That has been a common explanation given to news reporters from people – mostly younger people – going to beaches, bars and other large gatherings. They say they feel safe. They are wrong.

The Centers for Disease Control and Prevention estimates that about two-thirds of COVID-19 infections come from people who show no symptoms, either because their cases are mild or the symptoms haven’t developed yet.

“You cannot tell by looking at someone,” Tuznik said. “The person behind you, in front of you or next to you could be spreading the virus around like crazy. That’s why you social distance. That’s why you wear a mask.”

Biggest mistake: Not wearing a mask.

Masks help protect you from catching COVID-19. Masks protect your friends, family and neighbors if you have the virus – and you may not know you have it.

“All you need to do to go out in the world and to help us all recover is wear a small piece of cloth,” Tuznik said. “That’s asking so little. Or do you want to be the reason someone you love is in intensive care?”

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