According to research published in the journalJAMA Network Open on Friday, a second and third dose of Pfizer and BioNTech's Covid-19 vaccine fades the immunity against the omicron coronaviruses.
Researchers found that the Antibody Responses are Transient after a second and third Pfizer dose.
The levels of omicron-specific antibodies can target the virus and stop it from replicating after a second and third dose of Pfizer's shot.
The researchers said that the levels of antibodies specific to the original and delta coronaviruses were much lower than the levels that were found in other people.
The proportion of omicron-specific antibodies detected in participants dropped from 76% four weeks after the second shot to 53% at weeks eight to 10 and 19% at weeks 12 to 14.
The shot generated a response in most people for at least eight weeks, compared to four weeks after the second dose.
After the booster shot, the original variant's levels fell as early as three weeks after, followed by 5.6-fold for delta and 5.4-fold for omicron.
The researchers said that additional booster shots might be needed to combat the variant, particularly among older people.
The benefits of a third vaccine dose are acknowledged by experts and regulators. There is less agreement on whether additional shots are needed beyond that and whether frequent boosting will be practical. The main focus of studies evaluating vaccines is neutralizing antibodies, but they are not the only part of the immune system protecting humans against disease. T cells, which are part of the immune system, are more durable and can reduce the chance of serious illness if you get an infectious disease. Data shows they offer much more durable protection than the primary function of vaccine is to prevent infections.
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