Potency of Pfizer, Moderna vaccines falling with passage of time: Study

August 26, 2021:

The study was conducted at eight distinct locations in the US and found that the effectiveness of the vaccine in a group of fully vaccinated health workers had reduced from the high of 91 percent earlier to 80 percent in the recent analysis.

In what appears to be an unfortunate development, scientists have found that the potency or effectiveness of Coronavirus vaccines has diminished in recent months. The findings which have been published by the scientists at University of Utah indicate that the vaccine potency of Coronavirus has reduced in the last few months. As part of their analysis, the group of scientists conducted their study at eight distinct locations in the US and found that the effectiveness of the vaccine in a group of fully vaccinated health workers had reduced from the high of 91 percent earlier to 80 percent in the recent analysis, the Indian Express reported.

The team of scientists relied on the findings of the RT-PCR test results to come to the result of their research. It is also pertinent to note that the study did not attempt to measure if there was a considerable drop in the efficacy of the vaccine when it comes to protection against the severe manifestation of the disease or against hospitalisation and death.

Analysing the findings of their study, the authors have said that one of the contributing reasons to the decreasing potency could be waning of the vaccine-activated defences against the virus with the passage of time. Another probable reason highlighted by the scientists might be less effectiveness of the vaccines against the Delta variant which has been the variant being reported in large numbers in the United States. The study has been carried in the Morbidity Mortality Weekly Report from the US Centers for Disease Control and Prevention (CDC).

More than 4136 health workers who had previously not contracted the virus were part of the study by scientists. Out of the 4136 participants, 2976 participants had been fully vaccinated during December 2020 and March 21, while the rest had not been vaccinated. The study found that the vaccines were only 80 percent effective against the individuals who had been fully vaccinated with the Pfizer, Moderna and Johnson and Johnson vaccines. The scientists further said that the effectiveness of the vaccines might dip further with the passage of more months. Financial Express