Pfizer COVID-19 Vaccine’s Effectiveness Falls Below 50 Percent After 5 Months: Study

The effectiveness of the Pfizer-BioNTech COVID-19 vaccine falls below 50 percent after five months, according to a new study published in The Lancet medical journal on Oct. 4.

The study (pdf), which was funded by Pfizer, aimed to evaluate the overall variant-specific effectiveness of the companies’ vaccine against CCP (Chinese Communist Party) virus infections and COVID-19-related hospital admissions over time.

Researchers analyzed electronic health records of more than 3.4 million men and women who were members of the health care organization Kaiser Permanente Southern California between Dec. 14, 2020, and Aug. 8, and assessed the vaccine effectiveness up to six months after they were inoculated.

They found that the Pfizer vaccine was 88 percent effective in the first month after full vaccination, but dropped to 47 percent effectiveness after five months.