Study: Effectiveness of Pfizer Vaccine against COVID-19 Decreases after 6 Months

Data collected by US scientists showed that the effectiveness of the Pfizer / Biontech anti-coronavirus vaccine decreased to 47% from 88% within six months after the second dose.

The researchers of US health agencies relied on this data when they decided to grant booster doses of the vaccine to sustain the immunity of the human body.

The data, published on Monday in the Lancet Medical Journal, stated that the analysis of data on the effectiveness of the vaccine in preventing symptoms that require hospitalization, or that lead to death as a result of COVId-19, showed that it continues to be effective by 90 percent for at least six months, even in the face of a mutant Delta which is spreading fast, according to Reuters.

Researchers said that the reason is that its effectiveness declines as time being passed, and not in confronting strains of the deadly virus that are more capable of spreading the original one.

The data show that the effectiveness of the vaccine against the Delta mutant was 93 percent after the first month and then decreased to 53 percent after four months.

In the face of other mutations of the Coronavirus, the effectiveness decreased to 67 percent from 97 percent.

The US Food and Drug Administration  (FDA) has approved a booster dose of the Pfizer/Biontech vaccine for older adults and some Americans who are more susceptible to infection.

Scientists demanded more data before recommending that booster doses be given to everyone who received the vaccine.

On the other hand, a Tunisian medical official said that the acquired immunity from the "Pfizer" and "Moderna" vaccines declines after months, calling for a vaccination with a third dose.

This came in statements made, yesterday, Monday, by Moez Al-Sharif, a member of the national campaign for vaccination against the Coronavirus, which was reported by the private Nessma channel.

Al-Sharif considered that the vaccines, Pfizer and Moderna, "have good effects, but the person gradually loses his immunity over time, so the third dose was considered."

He recommended receiving the third dose of the coronavirus vaccine, especially for the elderly.