More than 60 million Americans have been fully vaccinated against COVID-19, according to the Centers for Disease Control and Prevention. The large-scale vaccination efforts underway across the U.S. to vaccinate those eligible come at a time health care experts are concerned about people becoming lax about safety precautions.

"We are all worried that there's going to be a fourth wave," said Dr. Abinash Virk, an infectious diseases expert and co-chair of Mayo Clinic's COVID-19 Vaccine Allocation and Distribution workgroup. "We've had three waves already. And each time the waves went down, everyone became very excited and took their masks off and stopped taking all the precautions that we recommended. At this time, it is the same situation."

Virk says people want to get back their normal lives but there's new information that's giving him pause.

"The recent data has shown that there's a slight uptick in the number of COVID-19 cases. The most worrisome concern we now have is that during the last few days and weeks is that the variants have increased substantially, particularly in the East Coast, the Midwest and the Sunbelt areas.

"The concern is that the fourth wave may be largely made of the COVID-19 variants especially since many people are still not vaccinated. And that's the reason why we have to continue wearing masks in public, social distance and practice good hand hygiene until substantially more of the US population is vaccinated."

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A goal of the COVID-19 vaccination effort is to reach population immunity, also known as herd immunity.

"What we mean by herd immunity is that most of the population or a large percent of the population is protected against a certain disease," Virk said. "You can get that from natural infection, or you can get it from the vaccination. Based on the fact that we've had only about 20% of the population vaccinated — although we have had about 30 million-plus people who've had COVID-19 infection — we're nowhere close to what we consider herd immunity. What we consider good herd immunity at a level that's going to be helpful to turn this pandemic around is that about 70-to-80% of the population has to be protected. And we're not anywhere close to that yet."

The good news is that the vaccines are shown to be effective and safe. "What the data shows us is that these vaccines are extremely safe," Virk said. "Not only that, but these vaccines are also very effective in preventing COVID-19 and particularly preventing people from getting into the hospital or dying. These vaccines have really proven themselves in terms of their effectiveness and their safety."

The CDC offers these tips to help you prevent COVID-19 infection:

  • Wear a mask that covers your nose and mouth to help protect yourself and others.
  • Stay 6 feet apart from others who don’t live with you.
  • Get a COVID-19 vaccine when it is available to you.
  • Avoid crowds and poorly ventilated indoor spaces.
  • Wash your hands often with soap and water. Use hand sanitizer if soap and water aren’t available.