07-09-2021, 09:15 AM
![[Image: 210315221535-pfizer-vaccine-medium-plus-169.jpg]](https://cdn.cnn.com/cnnnext/dam/assets/210315221535-pfizer-vaccine-medium-plus-169.jpg)
(CNN)Pfizer said Thursday it is seeing waning immunity from its coronavirus vaccine and says it is picking up its efforts to develop a booster dose that will protect people from variants.
It said it would seek emergency use authorization from the US Food and Drug Administration for a booster dose in August after releasing more data about how well a third booster dose of vaccine works.
"As seen in real world data released from the Israel Ministry of Health, vaccine efficacy in preventing both infection and symptomatic disease has declined six months post-vaccination, although efficacy in preventing serious illnesses remains high," the company said in a statement emailed to CNN.
"Additionally, during this period the Delta variant is becoming the dominant variant in Israel as well as many other countries. These findings are consistent with an ongoing analysis from the Companies' Phase 3 study," it added.
"While protection against severe disease remained high across the full six months, a decline in efficacy against symptomatic disease over time and the continued emergence of variants are expected. Based on the totality of the data they have to date, Pfizer and BioNTech believe that a third dose may be beneficial within 6 to 12 months following the second dose to maintain highest levels of protection."
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