(NEW YORK) Hours after Pfizer announced it was ramping up efforts to develop a third dose for its two-shot COVID-19 vaccine, the Centers for Disease Control and Prevention and the Food and Drug Administration issued a joint statement Thursday saying fully vaccinated people don't need it, according to CNN.
"Americans who have been fully vaccinated do not need a booster shot at this time," they said.
But Pfizer said it is seeing evidence to suggest that people's immunity begins to wane even after they have received both shots of the Pfizer-BioNTech vaccine, citing Israel's health ministry, which said earlier this week that the efficacy of Pfizer's vaccine dropped from over 90% to about 64% when dealing with the more contagious Delta variant of COVID-19.
"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," Pfizer told 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."
The drugmaker said it plans to publish data soon on the effects of a third dose of vaccine and would apply to regulators for emergency use authorization.
The FDA and CDC said they continue to review new data and will take action on booster doses "when the science demonstrates that they are needed."
Per CNN, more than half of the 158 million fully vaccinated people in the U.S. received Pfizer's vaccine.