Two recently published real-world studies have confirmed that immunity significantly wanes after the second dose of Pfizer vaccine.
Since the emergence of COVID vaccines, the Pfizer vaccine has been at the forefront of the pandemic. Its mRNA technology has helped reduce infections and hospitalizations. Its effectiveness even earned it a full FDA approval earlier this year. Thus, becoming the first COVID vaccine to reach the milestone. The vaccine manufacturer has also pushed for a third dose of its vaccine, citing its effectiveness at increasing immune response in individuals. Now two new real-world studies recently published in the New England Journal of Medicine have further added to the need for a third dose. According to both studies, a person’s immunity significantly wanes within months of the second dose of the Pfizer vaccine.
We found that a significant and rapid decrease in humoral response to the BNT162b2 vaccine was observed within months after vaccination.
study authors
The study from Israel looked at levels of anti-spike IgG and neutralizing antibodies among 4,800 vaccinated healthcare workers. Researchers tested them monthly for a period of six months after the second dose. Although the IgG antibodies decreased at a consistent rate, the neutralizing antibodies decreased rapidly in the first 3 months. The waning immunity was more pronounced among men, immunocompromised individuals, and those aged 65 years or above.
Study Provides Evidence for Booster Shots
The study from Qatar was a real-world analysis of breakthrough infections among the vaccinated population of the region. Between December 2020 and September 2021, more than 900,000 people in the Gulf nation had received two doses of Pfizer. Similar to the study from Israel, researchers noted a decrease in immunity after the Pfizer vaccine. However, the effectiveness of the vaccine against hospitalizations and deaths remained above 90%.
BNT162b2-induced protection against infection builds rapidly after the first dose, peaks in the first month after the second dose, and then gradually wanes in subsequent months. The waning appears to accelerate after the fourth month, to reach a low level of approximately 20% in subsequent months.
study authors
Researchers believe the casualness of vaccinated individuals against COVID-19 precautions might be to blame for the increasing breakthrough infections.
Based on Pfizer’s recent documents, the CDC updated its guidelines for booster shots to include those aged 65 years and above.
Reference:
Levin, Einav G., et al. “Waning Immune Humoral Response to BNT162B2 Covid-19 Vaccine over 6 Months.” New England Journal of Medicine, 2021, doi:10.1056/nejmoa2114583.
Chemaitelly, Hiam, et al. “Waning of bnt162b2 Vaccine Protection against SARS-COV-2 Infection in Qatar.” New England Journal of Medicine, 2021, doi:10.1056/nejmoa2114114.
