The Effectiveness of COVID-19 Vaccines Against the Omicron Variant

With the world's dinosaur media now distracted by all things Russian/Ukrainian, mercifully, the COVID-19 pandemic has become yesterday's news.  While I've weaned myself from covering most of the recent pandemic news, a new study that appeared in The New England Journal of Medicine provides us with the latest information on the effectiveness of the booster vaccines against the omicron variant.

  

The study entitled "Covid-19 Vaccine Effectiveness against the Omicron (B.1.1.529) Variant", authored by Dr. N. Andrews and Dr. J. Stowe et al opens with this sentence:

 

"A rapid increase in coronavirus disease 2019 (Covid-19) cases due to the omicron (B.1.1.529) variant of severe acute respiratory syndrome coronavirus 2 in highly vaccinated populations has aroused concerns about the effectiveness of current vaccines."

  

Let's start with this definition:

 

"A test-negative case-control study design is commonly used to determine the effectiveness of vaccines.  The The “test-negative design” , in which the same clinical case definition is used for enrollment of both cases and controls, and laboratory testing is subsequently used to distinguish which patients were cases and which were controls."

  

The authors used a test-negative case-control study design to estimate the effectiveness of the COVID-19 vaccines against symptomatic disease caused by the omicron and delta variants in England.  Vaccine effectiveness (VE) was calculated after primary immunization with two doses plus a booster dose of the Pfizer-BioNTech, AstraZeneca or Moderna COVID-1 vaccines.  The study took place between November 27, 2021 and January 12, 2022 and involved a total of 886,774 eligible persons infected with the omicron variant, 205,154 eligible persons infected with the delta variant and 1,572,621 eligible test-negative control persons with all persons being aged 18 years and older.  Vaccine effectiveness was assessed in five year bands from ages 18 to 89 inclusive.  

  

Let's look at some of the more interesting findings of the study, breaking it down by vaccine manufacturer and variant:

 

Vaccine effectiveness against the delta variant:

 

1.) Pfizer/BioNTech - delta variant

 

dose 1 - 45.2 percent in weeks 0 to 3, 72.3 percent after 4 weeks 

 

dose 2 - 90.9 percent weeks 2 to 4, dropped to 62.7 percent in week 25

 

booster dose - 92.3 percent in week 1, dropped to 89.9 percent in week 10

 

Pfizer/BioNTech - omicron variant

 

dose 1 - 42.8 percent in weeks 0 to 3, dropped to 31.5 percent in week 4

 

dose 2 - 65.5 percent weeks 2 to 4, dropped to 8.8 percent in week 25

 

booster dose - 66.9 percent in week 1, dropped to 45.7 percent in week 10

 

2.) Moderna - delta variant

 

dose 1 - 60.1 percent in weeks 0 to 3, dropped to 57.4 percent in week 4

 

dose 2 - 94.5 percent in weeks 2 to 4, dropped to 84.5 percent in week 25

 

booster dose - 95.3 percent in week 1, rose to 96.4 percent in weeks 2 to 4

 

Moderna - omicron variant

 

dose 1 - 47.9 percent in weeks 0 to 3, dropped to 31.9 percent in week 4

 

dose 2 - 75.1 percent in weeks 2 to 4, dropped to 14.9 percent in week 25

 

booster - 68.1 percent in week 1, dropped to 66.3 percent in weeks 2 to 4

 

3.) AstraZeneca - delta variant

 

dose 1 - 42.9 percent in week 4

 

dose 2 - 82.8 percent in weeks 2 to 4, dropped to 43.5 percent in week 25

 

booster - 77.1 percent in week 1, rose to 83.3 percent in weeks 5 to 9

 

omicron variant

 

dose 1 - 17.7 percent in week 4

 

dose 2 - 48.9 percent in weeks 2 to 4, dropped to -2.7 percent in week 25

 

booster - 57.7 percent in week 1, dropped to 46.7 percent in weeks 5 to 9

 

The authors also studied the mixing of the two mRNA vaccines and the adenovirus vector vaccine and the impact of the mixing on the effectiveness of the vaccines against both the delta and omicron variants.  If you wish to see this data for yourself, please click here.

Let's summarize by looking at the authors' conclusions.  First, the authors noted that after two doses, vaccine effectiveness waned rapidly with very limited vaccine effects seen from 20 weeks aft ere second dose of any vaccine.  Booster doses did result in a substantial increase in protection against mild infection, however, once again, the protection waned quickly as time passed.  The authors also noted that they were unable to determine the degree of protection that the vaccines offered against sever cases of the disease because of the use of the test-negative case-control method due to the small number of omicron cases resulting in hospitalization. The authors found that two doses of the Pfizer/BioNTech and AstraZeneca vaccine are "insufficient to give adequate levels of protein against infection with the omicron variant and mild disease.  Boosting with the Pfizer/BioNTech vaccines provided a substantial increase in protection against mild disease, although waning occurred over time."  They do note that "boosters will probably offer even greater levels of protection against severe and fatal disease" although this was not part of the study.

 

Given governments' push to get citizens triple vaccinated, this research clearly shows that the effectiveness of the booster vaccines show signs of waning effectiveness after only a 9 week period of time, suggesting that the current vaccines will not prevent the ongoing rise in the number of omicron cases globally.  Now that there is yet another variant, the imaginatively named BA.2 variant (which appears to be a the second sublineage of Omicron) that has appeared on the scene, the vaccines could prove to be even more useless than they already are.