Study: The effectiveness of the Pfizer and Moderna vaccines against the delta mutant decreased to 66%

Washington-Sana

A study conducted by the Centers for Disease Control and Prevention in the United States showed that the efficacy of the Pfizer and Moderna vaccines against the Corona virus has decreased from 91 to 66 percent since the delta mutation became prevalent in the United States.

The French Press Agency quoted the study as saying that tests were conducted in health care centers and hospitals in six US states to study the effectiveness of the two vaccines, and according to weekly examinations on volunteers to monitor infections with symptoms and those without any symptoms, the effectiveness of the two vaccines between December 2020 and April 2021 in preventing infection with the virus was up to In the weeks when the delta mutant became dominant and responsible for more than 50 percent of infections, the efficacy decreased to 66 percent.

The study stressed that this decline may not be caused exclusively by the delta mutant, but rather it may be due to the decline in effectiveness with the passage of time.

Several studies indicated a low efficacy of vaccines against the delta mutant, despite the difference in percentages from one study to another.

The low efficacy of vaccines is one of the reasons that prompted the US health authorities to launch a campaign to give a third booster dose of the Pfizer and Moderna anti-Covid 19 vaccines to all Americans, starting from next September 20.

Delta became the dominant mutation in the United States at the beginning of last July and is currently responsible for more than 98 percent of infections.