Efficacy of Moderna, Pfizer and Johnson & Johnson COVID-19 Vaccines Against the Omicron Variant

December 21, 2021

In the past month, COVID-19 news has shown a spotlight on covering the spread of the Omicron variant, which has now been labeled the leading variant in the U.S. and accounts for three-fourths of total cases. Data coming out of South Africa, where the Omicron variant was first identified, shows a much lower hospitalization rate than initially expected, with signs that the current wave may already be peaking in South Africa. In fact, national data shows that while the average number of infections jumped by almost 5x in the second week of December, less than 2% resulted in hospitalization (1, 2).

Since the Omicron variant was identified as a variant of concern, Pfizer, Moderna, and Johnson & Johnson have been testing the efficacy of their vaccines, including booster doses, as an extra form of protection. Below are synopses of how each vaccine fares against the Omicron variant according to the latest data:


Moderna found the two-dose primary series of their COVID-19 vaccine to be significantly less effective at preventing infection against the Omicron variant than the alpha or “wild type” variant. A 50-microgram booster, which is half the size of the primary series, increased antibodies by ~37x. While this is a significant increase, a 100-microgram booster dose was shown to increase antibody levels by ~83x compared to antibody levels following the primary series.


Earlier in December, Pfizer released data from a laboratory study demonstrating a booster dose of their COVID-19 vaccine also increased antibody levels to neutralize the Omicron variant. While “two doses show significantly reduced neutralization titers,” three doses increased antibody titers by 25x, providing protection comparable to that of two doses against the alpha variant. Two doses have demonstrated protection against severe disease; results were collected from under 40 samples.


Johnson & Johnson’s vaccine has been shown to fare the worst against Omicron, providing low levels of protection. The ACIP, the advisory committee to the CDC, convened last week to discuss Johnson & Johnson COVID-19 vaccines and booster doses in light of Omicron and regarding cases of thrombosis with thrombocytopenia (TTS). TTS has been verified by the FDA and CDC as a rare but possible adverse event after receiving the J&J vaccine. On Thursday, the ACIP and CDC recommended against the use of a second J&J dose following the primary series. The CDC’s official stance now recommends an mRNA vaccine after the initial J&J primary dose. Studies have shown that a J&J COVID-19 primary series followed by an mRNA vaccine as a booster dose provides a significant jump in antibodies. Read more about mixing and matching COVID-19 vaccine doses here.