• By Deb Balzer

Reinfection rates of omicron and why people need to take this seriously

December 20, 2021
close up of coronavirus representing COVID-19 with the words omicron variant

The infection rate of omicron, the highly infectious variant of COVID-19, is doubling about every two days, says Dr. Gregory Poland, an infectious diseases expert and head of Mayo Clinic's Vaccine Research Group

"We do know from early data that this virus replicates about 70-fold faster than the delta variant. And we see manifestations of that. For example, for somebody who's previously been infected with COVID, their chance of getting reinfected with omicron is almost 5½-fold higher than reinfection with delta."

Watch: Dr. Gregory Poland talks about the reinfection rate of omicron.

Journalists: Soundbites are in the downloads at the end of the post. Please courtesy: "Gregory Poland, M.D./Mayo Vaccine Research Group/Mayo Clinic."

Breakthrough infections are also happening. Dr. Poland says because of the extraordinary transmissibility of the omicron variant, and the waning of immunity from vaccine or infection over time, there is a decrease in protection against infection.

"If you look after two doses of vaccine, and you wait at least three months, your protection against infection or hospitalization goes down to about 30%–40%. If you get that booster dose, in essence, a third dose, your protection against hospitalization, jumps back up to what it had been, if not higher, so about 75%–80% protection against infection and hospitalization. Notice I didn't say 100%. That's why we're still wearing masks. That's why we're still distancing."

Dr. Poland says there are many questions about the virus as well as misinformation about safety and symptoms.

"When we look at the latest data that just came out from London, so a context epidemiologically, socially and culturally much like ours, unlike South Africa, they are not seeing a decrease in hospitalization rates or severity of symptoms with omicron. Their omicron outbreak is ahead of ours. We had better take that very seriously."

"When you take a virus that's much more transmissible and has an equal chance of causing hospitalization and severe symptoms, you're talking about a virus that has the capacity to cause a surge in hospitalization and deaths, and that underscores the recommendation that you continue to wear masks, continue to distance, continue to sanitize your hands and get that booster dose of vaccine."

For those who are gathering with family and friends for the Christmas holiday, Dr. Poland says he wants everyone to gather safely ― not spread disease to one another ― and that means everyone is fully vaccinated with a booster vaccine.

"The second thing you want to do is get a rapid test before you're going to gather with people that you have not immediately been around over the last week or so. The problem now is there's this surge demand for testing as people waited to make appointments. If it's not possible to do that, I would give strong consideration, if possible, to holding your celebration outdoors, or if that's not possible, masking. I know that won't be popular. But if you say our goal is to keep everybody safe, then it's boosters, rapid testing and if you can't do those, masking."


For the safety of its patients, staff and visitors, Mayo Clinic has strict masking policies in place. Anyone shown without a mask was recorded prior to COVID-19 or recorded in an area not designated for patient care, where social distancing and other safety protocols were followed.

Information in this post was accurate at the time of its posting. Due to the fluid nature of the COVID-19 pandemic, scientific understanding, along with guidelines and recommendations, may have changed since the original publication date.

For more information and all your COVID-19 coverage, go to the Mayo Clinic News Network and mayoclinic.org.

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Dec. 17, 2021 - Mayo Clinic COVID-19 trending map using red color tones for hot spots