RELATED: If You Got Pfizer, You May Not Have Antibodies Against Delta After This Long. On Oct. 4, The Lancet published a study that examined the Pfizer vaccine’s effectiveness over six months. According to the study, the effectiveness of Pfizer at preventing COVID infection dropped to 47 percent from 88 percent six months after the second dose. However, the vaccine’s effectiveness at preventing severe outcomes remained high. Pfizer was 90 percent effective at preventing hospitalization and death related to COVID for at least six months, even as the highly transmissible Delta variant became the most dominant strain of the virus. The study asserted that the reduction in the vaccine’s effectiveness was primarily related to waning immunity over time, rather than the Delta variant evading the vaccine. Luis Jodar, MD, senior vice president and chief medical officer at Pfizer vaccines, told Reuters, “Our variant-specific analysis clearly shows that the vaccine is effective against all current variants of concern, including Delta.” Vaccine effectiveness against the Delta variant began at 93 percent after the first month, then dropped to 54 percent after four months. Meanwhile, against other COVID strains, efficacy fell from 97 percent to 67 percent. “To us, that suggests Delta is not an escape variant that is completely evading vaccine protection,” study leader Sara Tartof, PhD, told Reuters. RELATED: For more up-to-date information, sign up for our daily newsletter. On Sept. 22, the U.S. Food and Drug Administration (FDA) authorized booster doses of the Pfizer vaccines for certain populations of people in the U.S. Those who are now eligible for a booster shot include people over 65 years of age, people at high risk for severe COVID, and people whose frequent exposure to COVID at work or an institution put them at high risk of severe COVID. According to Reuters, U.S. health agencies consulted the data in the study when deciding whether or not Pfizer recipients needed a booster shot. On Oct. 14, the FDA will meet to discuss the question of booster shots for Moderna recipients. However, since Moderna’s effectiveness doesn’t appear to wane as much as Pfizer’s, the vaccine company may not have as strong a case for booster doses. On Aug. 5, Moderna announced that its vaccine was still about 93 percent effective six months after the second dose, which is only a slight drop from its original reported efficacy of 94 percent during clinical trials.ae0fcc31ae342fd3a1346ebb1f342fcb RELATED: If You’re Over 60, This Is How Much a Pfizer Booster Protects You, Study Says.
