Skip to main content
Mayo Clinic Health System
  • Patient Online Services
  • Pay Bill Online
  • Request an Appointment
    • Services
    • Providers
    • Locations

      Minnesota

      • Adams
      • Albert Lea
      • Austin
      • Belle Plaine
      • Blooming Prairie
      • Butterfield
      • Caledonia
      • Cannon Falls
      • Fairmont
      • Faribault
      • Janesville
      • Kenyon
      • Lake City
      • Le Sueur
      • Mankato
      • Montgomery
      • New Prague
      • New Richland
      • Northfield
      • Owatonna
      • Plainview
      • Red Wing
      • Sherburn
      • St. James
      • St. Peter
      • Waseca
      • Waterville
      • Wells
      • Zumbrota

      Wisconsin

      • Arcadia
      • Barron
      • Bloomer
      • Chetek
      • Chippewa Falls
      • Eau Claire
      • Ellsworth
      • Glenwood City
      • Holmen
      • La Crosse
      • Menomonie
      • Mondovi
      • Onalaska
      • Osseo
      • Prairie du Chien
      • Rice Lake
      • Sparta
      • Tomah

      Iowa

      • Decorah
      • Lake Mills

      View map
    • Classes/Events
    • Blog
    • Wellness
    • Referrals
    • COVID-19
    • Influenza

    Recent Posts

    • People playing Jenga
      Speaking of Health
      Preserving pandemic positives
      January 27, 2023
    • Person outdoors in the cold wearing hat, hoodie and facemask
      Speaking of Health
      Is the extreme cold bad for your lungs?
      January 27, 2023
    • Hands holding hand with ring
      Speaking of Health
      Dementia-related pain: What caregivers need to know
      January 26, 2023
    Featured Topics
    • Behavioral Health
    • Cancer
    • Children's Health (Pediatrics)
    • COVID-19
    • COVID-19 Vaccine
    • Exercise and Fitness
    • Heart Health
    • Men's Health
    • Neurosurgery
    • Obstetrics and Gynecology
    • Orthopedic Health
    • Weight Loss and Bariatric Surgery
    • Women's Health
    Join our email newsletter
    Featured Topic
    Wednesday, July 21, 2021

    Unvaccinated at highest risk of delta variant infection

    Topics in this Post
    • COVID-19 Vaccine
    • COVID-19
    • Infectious Diseases
    • Hot topics
    Gloved hands giving COVID-19 vaccination in bare arm

    A highly transmittable form of COVID-19 known as the delta variant is spreading globally. Now a subvariant known as delta-plus has been identified.

    "Delta-plus just means that there's been an additional mutation in the delta variant," says Gregory Poland, M.D., an infectious diseases physician and researcher at Mayo Clinic. "We have not really seen that take off yet. And that's probably because it's being outcompeted by the delta variant. If you look at the original virus and you say there was a certain amount of infectivity associated with that, the U.K., or alpha variant, was about 50% more infectious than the original virus. The delta virus is 50% to 60% more infectious than the alpha variant."

    The unvaccinated populations remain the highest risk group. The good news, Dr. Poland says, is that the COVID-19 vaccines are effective.

    "The vaccines we have available in the U.S. ― the Johnson and Johnson vaccine, the Pfizer vaccine, the Moderna vaccine and soon the Novavax vaccine ― are all extraordinarily effective against death, hospitalization and severe disease due to the delta variant, as well as the other variants."

    "That doesn't mean it (vaccination) offers 100% protection against lesser degrees of infection," says Dr. Poland. "Instead of getting severe disease or being hospitalized, might you have a small chance of asymptomatic or mild infection, or even a very small chance of moderate infection because not everybody has a strong immune system. Some people have differences in their genetics that don't allow them to have a strong immune response, or have diseases or treatments that compromise our immune systems — including advanced age.

    The delta virus is among several coronavirus variants circulating. Viruses constantly mutate, explains Dr. Poland.

    "When we use the term 'variant,' we are talking about a mutation that occurs in the virus that changes how that virus infects us. It could make it less infectious, which would be great. That's not happening. Instead, these mutations are learning how to become more and more infectious, more and more dangerous, which is why the big public health push to get people kind of past their fears and concerns to say this is a lifesaving vaccine."

    Learn more about COVID-19:

    • Mayo Clinic Q& A: How different types of COVID-19 vaccines work
    • Mayo Clinic Q&A podcast: On the verge of predicted surge with COVID-19 delta variant
    • Respiratory illnesses on the rise with symptoms similar to COVID-19

    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.

    Research disclosures for Dr. Gregory Poland.


    For the safety of our patients, staff and visitors, Mayo Clinic has strict masking policies in place. Anyone shown without a mask was either recorded prior to COVID-19 or recorded in a non-patient care area where social distancing and other safety protocols were followed.
    Topics in this Post
    • COVID-19 Vaccine
    • COVID-19
    • Infectious Diseases
    • Hot topics

    Related Posts

    Child with arm around parent shoulder Helping kids struggling with the ever-changing COVID-19 pandemic
    Gloved hands placing bandage on arm Recent infection could affect COVID-19 vaccination
    Grey haired person wearing glasses and looking to side Are you experiencing frustration with the COVID-19 pandemic?

    Stay Connected

    • Contact Us
    • Notice of Nondiscrimination
    • Notice of Privacy Practices
    • Terms of Use
    • Privacy Policy
    • About Us
    • Careers
    • Volunteer
    • Donate
    • For Patients & Visitors
    • Financial Assistance
    • Community Resources
    • Mayo Clinic Connect
    • For Medical Professionals
    • Press Room
    • Mayo Clinic
    • Home
    © 2018 - 2023 Mayo Clinic Health System