Update on Vaccines and the Omicron Variant

Information gathered from a blog from Dr. Francis Collins, Director, National Institute of Health.

Omicron is a variant of SARS-CoV-2, the virus that causes COVID-19. There are many mutations of Omicron found in the spike protein (that part of the coronavirus that the Pfizer and Moderna vaccines attack). These genetic changes provide the possibility that Omicron could cause breakthrough infections in people already vaccinated with the Pfizer or Moderna vaccine.

The new data coming out present some encouraging results. Although there is a decline in the ability of 2 doses of the vaccine to prevent contracting COVID-19, a booster or 3rd dose may better protect people. The data show that getting a booster will help protect people already vaccinated from breakthrough or possible severe infections with Omicron during this winter.


One of the studies from the Africa Health Institute shows that Omicron relies on the ACE2 receptor to infect human lung cells. Since the vaccines already developed protect this receptor they will be useful in combatting this new variant attack on the lungs. The study also showed that people who were vaccinated with 2 doses and had been infected with COVID-19 showed good antibody levels against the Omicron variant, unlike people who had been vaccinated but had not contracted COVID-19. There is a decline in the ability of people with only 2 doses of the vaccine to withstand this variant.

Pfizer also did a study taking samples from people with 2 doses of the vaccine and comparing them with samples from people who had 2 doses and the booster. The samples with only 2 doses had a more than 25-fold decline against the original COVID-19 virus. This suggests that 2 doses may not be enough to fight against the Omicron variant.

It is very encouraging that the studies also showed that an additional booster dose raised the ability of the vaccine to combat the Omicron variant at the same level as 2 doses against the original virus. This shows that getting a booster dose of the vaccine will give good protection against the Omicron variant.

Scientists all over the world are monitoring the severity of the Omicron variant.  There is still much information to be found. As of now it appears that the Omicron variant is highly transmissible but it may produce milder illness than Delta. The Delta variant is currently the predominant COVID-19 strain in the United States. There is still a tremendous amount of research to be done.

It is clear that vaccines and booster shots (if you are eligible) are the best way to combat COVID-19. Wearing a mask offers good protection against the spread of COVID-19.
If you have symptoms or think you have been exposed, get tested and stay home.

National Institute of Health – COVID-19 Research

Africa Health Research Institute, (Sigal Lab) Durban, South Africa

Center for Disease Control