Two doses of Oxford AstraZeneca and Pfizer-BioNTech COVID-19 vaccines are substantially less effective to fight omicron compared to other variants, according to a study by researchers at University of Oxford.
However, the researchers noted that a booster shot would improve immunity against the new, highly transmissible variant.
The study included researchers to include form blood sample of people 28 days after their second dose of either vaccine.
When omicron was introduced to those samples, scientists reported “a substantial fall” in the neutralizing antibodies that fight off Covid compared to the immune responses seen against earlier variants.
“This will likely lead to increased breakthrough infections in previously infected or double vaccinated individuals, which could drive a further wave of infection, although there is currently no evidence of increased potential to cause severe disease, hospitalization or death,” the study’s authors said.
The pre-print study, which is yet to be peer reviewed, was published on the MedRxiv server.