COVID-19 Vaccines and Omicron: Vaccines by the Numbers


  • The Omicron occurs in the form to be less efficient against infection when compared to a two-shot course of mRNA vaccines or the one-shot J&J vaccine.
  • According to current data, mRNA vaccines (Pfizer-BioNTech or Moderna) give the best protection against illness and hospitalization, as recommended by the CDC.
  • According to current estimates, immunizations provide 30 to 40% protection against illness and over 70% protection against hospitalization when used without boosters.
  • Newer research confirms that a third dosage improves antibody production and infection efficacy to roughly 75% for mild disease and 88 percent for severe disease.

Omicron is fast spreading over the world, and scientists are scrambling to figure out how vaccinations will fare against this new coronavirus type. The efficiency of existing COVID-19 vaccines in use against the Omicron variant has been evaluated in many early investigations. Although one- or two-dose vaccinations appear to provide less protection than booster vaccines, they nevertheless appear to protect against serious disease.

In both the lab and the real world, studies have shown that a complete immunization plus a booster dose provides better protection against Omicron infection. It’s crucial to note that the majority of these studies are in the lab and may not reflect the vaccines’ real-world effectiveness.

Vaccines appear to be less effective in Omicron compared to Delta

According to preliminary findings, vaccination efficacy against symptomatic Omicron infection is much lower than that of the Delta form. According to a paper from Imperial College London, the probability of reinfection with Omicron was 5.4 times higher than with the Delta version. Having COVID-19 previously provided minimal protection against Omicron reinfection.

“This is such a contagious virus that it can spread not only among the unvaccinated, where I believe it still has a very significant risk of causing serious disease that may require hospitalization, but it can also spread among the vaccinated, although the illness it produces among the vaccinated, particularly if you’ve had a boost, is generally mild and even without symptoms,” said Dr. William Schaffner, a professor of preventive medicine and infectious diseases at UC San Diego.

Despite the fact that hospitalization remains low for the time being, the Imperial College London study concludes that “no indication of Omicron having distinct severity from Delta.”

“Even if Omicron does not cause as severe illness as Delta, a rapid and massive outbreak of infections could overwhelm hospitals with sick patients.” “Those who have not had a third dose of an mRNA vaccine, as well as those who are unvaccinated, are at the biggest danger.

Omicron vs. 2-dose Pfizer vaccination

Only a few real-world studies have been able to quantify the Pfizer-BioNTech vaccine’s efficacy, and a number of lab experiments demonstrate that a booster boosts antibody production dramatically. “The research is mostly laboratory studies that would suggest that antibody levels created by boosting will have a notable impact on avoiding severe illness,” Schaffner said. Two doses of the AstraZeneca or Pfizer-BioNTech vaccines provided limited protection against infection with the Omicron strain, according to preprint research done by Oxford University.

However, a real-life South African trial indicated that two doses of the Pfizer-BioNTech vaccine were still effective in protecting patients from severe sickness. Two doses gave 70% protection against hospitalization and 33% protection against infection, according to the researchers. This was down from around 93 percent and 80 percent for the Delta model, respectively.

According to a trial published in the New England Journal of Medicine, a two-dose regimen of the Pfizer-BioNTech vaccine was 70% effective in preventing Omicron hospitalization. Although these lab studies show that antibodies, the body’s main line of defense against the coronavirus, can wane over time or be affected by mutations along with the virus’s spike protein, vaccines were able to generate other types of immune cells to fight infection.

“We now understand that vaccine-derived T cells continue to work against Omicron, and vaccine-derived B cells modify the new antibodies they produce to fight against variants,” says the researcher. So, I believe the clinical scenarios we’re seeing in those with preexisting immunity, vaccinated and even boosted folks [suggest] that immunizations are likely still protecting Omicron-infected people from severe illness,” she added.

According to preliminary research, two doses of the Pfizer-BioNTech COVID-19 vaccine provide 30 to 40% infection protection and roughly 70% hospitalization protection.

Omicron vs. Pfizer booster

According to preliminary research from the United Kingdom, boosters provide moderate to high vaccination efficacy against symptomatic illness, providing 70 to 75 percent protection in the weeks following the booster. Depending on whether the initial doses were from the AstraZeneca vaccination or the Pfizer-BioNTech vaccine, the researchers discovered a modest variation. Pfizer-BioNTech boosters were present in both groups.

Vaccination efficacy for persons who received the AstraZeneca vaccine climbed to roughly 71 percent two weeks following a Pfizer-BioNTech booster dose and to around 76 percent for those who first received the Pfizer-BioNTech vaccine. In terms of severe illness, Imperial College London modeling revealed that the Pfizer-BioNTech vaccine with a booster was 85.9% effective against Omicron and 97 percent effective against Delta.

Early results from Pfizer suggested that a booster dose considerably enhanced neutralizing antibodies, putting the vaccine’s protection against the original coronavirus variation close to what two doses offered. The findings came from a series of lab tests that looked at the ability of blood samples from those who had two doses of the vaccination and those who got a booster to neutralize the virus.

Antibodies obtained from those who did not get a booster exhibited a 25-fold lower neutralizing power against Omicron than the initial variety. Similarly, Israeli research comparing blood samples from two groups of healthcare professionals who had or had not taken Pfizer-BioNTech boosters discovered that the third dosage elevated antibody levels 100 times more than the first two doses.

According to the UK Health Security Agency’s (UKSHA) most current research, a third dosage provides much more protection. Early studies revealed those 6 months after the second dose, vaccination efficacy against Omicron had declined to 52 percent, but an mRNA booster increased it to 88 percent against hospitalization.

The Pfizer-BioNTech COVID-19 vaccine’s protection against infection increases to roughly 75% with a booster, and to 80 to 90% for severe illness. As new study findings become available, these figures may alter.

Omicron vs. Moderna vaccination

No tests have been done to determine the efficiency of the Moderna vaccine against Omicron, although experts believe it may be similar to the Pfizer vaccine. Blood samples from 30 persons who had received two doses of the Moderna vaccination revealed that their antibodies were at least 50 times less efficient at neutralizing Omicron, according to preliminary research.

Antibodies rose 37-fold with a 50-microgram booster. A 100-microgram booster, on the other hand, raised antibody levels by more than 80 times when given to immunocompromised persons as a third main dose. A UKHSA investigation of almost 200,000 cases found that three doses of the Moderna or Pfizer-BioNTech vaccines provided 88 percent protection against hospitalization.

A three-dose course of the Moderna vaccine is expected to be 88 percent effective against hospitalization, compared to 72 percent efficacy from two doses. To assess its efficacy against Omicron infection, further data is needed.

Omicron vs. Johnson & Johnson vaccination

Due to the uncommon risk of blood clots, a panel of the Centers for Disease Control and Prevention (CDC) suggested that patients acquire the Pfizer-BioNTech or Moderna vaccination instead of the Johnson & Johnson vaccine in December 2020.

Furthermore, research from South Africa revealed that in lab tests, the J&J vaccination elicited almost no antibodies against Omicron. “Those who were concerned after receiving the J&J vaccination (in the last several months) are no longer concerned. “However, if they’ve just had one dosage of J&J, they should be encouraged to have a booster,” Schaffner said in response to the new study.

Although it is not yet an official guideline, combining vaccines have been demonstrated to improve immunogenicity, which is why doctors are recommending Moderna or Pfizer-BioNTech booster doses for J&J. “With mRNA boosts, they (those who received J&J vaccinations) will obtain a considerably greater antibody level,” Schaffner said. Meanwhile, Gandhi stated that, while she agreed with the CDC panel’s conclusion in general, there were still certain people who would benefit from the vaccination.

There is insufficient evidence to establish the efficacy of the J&J vaccination. In terms of antibodies against Omicron, however, the single-shot vaccination appears to work poorly.

In Conclusion

According to Glatter, investigations have shown that those who are completely vaccinated and boosted with the Omicron version had the best protection against severe sickness and hospitalization. He did emphasize, however, that the Omicron variety can circumvent vaccination protection to some extent, “particularly in infecting those who have not got a booster.”

“This leads to more breakthrough infections, some of which are minor, but which are more dangerous in people who have had organ transplants, are immunocompromised, or are undergoing chemotherapy.” “Evidence suggests that boosters can restore protection, even against infection,” Glatter added. Schaffner also stated that he agreed with research indicating that two dosages were insufficient to protect against Omicron infection.

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