A healthy living blog from Marshfield Clinic Health System

Omicron, Delta: 4 things to know about these and other COVID variants

Editor’s note: This article was updated on January 3, 2022. COVID-19 information and recommendations are subject to change. For the most up-to-date information, visit the Centers for Disease Control and Prevention (CDC) website or view our most recent COVID-19 blog posts.

The SARS CoV-2 virus continues to naturally mutate into different strains of COVID-19. The delta variant was first detected in the U.S. in March 2021 and quickly became the dominant variant in the U.S. The omicron variant was first detected in the U.S. on December 1, 2021. These variants account for most of the new COVID-19 cases across the states, including Wisconsin.

It’s important to be fully vaccinated to protect yourself from the COVID-19 variants.

It’s important to be fully vaccinated to protect yourself from the COVID-19 variants.

Virus variants spread more quickly and easily

“The biggest issues with the delta and omicron variants are that they spread more easily than before,” said Kate Maguire, Infection Prevention director at Marshfield Clinic Health System. “With the original virus in the U.S., we would expect one person to potentially infect three people. However, according to BBC News article, alpha variant infects about four to five and delta is now five to eight or so.”

Scientists continue to monitor changes in COVID-19 variants and spikes in virus cases. Research is conducted to understand how variant changes affect how the virus spreads and how sick people will get from it.

COVID-19 vaccines are effective against the delta variant

Research has shown COVID-19 vaccines are extremely effective against severe illness, hospitalization and death from the delta variant. The CDC expects this to also be the case for the omicron variant.

Data showed the COVID-19 vaccines to be extremely effective in protecting fully vaccinated people from catching and spreading the SARS CoV-2 virus. While the vaccines are expected to provide protection from catching and spreading the delta and omicron variants, the vaccines are not expected to be as effective as they were against the original virus.

Dr. Rochelle Walensky, CDC director, stated in a telebriefing July 27, 2021, that research shows “individuals who are fully vaccinated may still be contagious” if infected by the delta variant. Walensky said the risk of a symptomatic infection is reduced sevenfold for fully vaccinated people, and the risk of hospitalization is reduced twentyfold.

CDC continues to monitor and research COVID-19 and vaccine effectiveness. Guidelines for fully vaccinated individuals was updated based on that research.

Masking recommended to protect yourself and others

In areas with substantial and high transmission, CDC recommends fully vaccinated individuals wear masks in public indoor settings, including schools, to help prevent the spread of the delta and omicron variants and protect others. The CDC defines high transmission as 50 cases or more per 100,000 people over the past seven days.

“A large portion of the world remains unvaccinated,” Maguire said. “It’s important to wear a mask in public if you are not vaccinated. We are seeing areas where delta variant is strong due to the lack of vaccination, masking and social distancing.”

Delta variant can lead to hospitalization and death

People infected with the delta variant are more likely to need hospitalization than those infected with earlier strains of the virus.

On July 17, 2021, the delta variant accounted for more than 83% of new COVID-19 cases.

“We are getting there, but we want everyone in our communities to be safe and healthy,” Maguire said. “Let’s put an end to these virus variants to have a safe and healthier community, one vaccine at a time.”

More data is needed to know if omicron will lead to more hospitalizations and death than the original virus or its variants.

Talk your provider about the COVID-19 vaccine. For common questions about the COVID-19 vaccine, visit our COVID-19 FAQ page.

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